SANITATION IN PANAMA

Concreted Ditch. Ancon.

SANITATION
IN PANAMA

BY
WILLIAM CRAWFORD GORGAS
CHIEF SANITARY OFFICER, PANAMA CANAL, SURGEON GENERAL, U. S. A.,
MAJOR GENERAL, U. S. A.

ILLUSTRATED
NEW YORK AND LONDON
D. APPLETON AND COMPANY
1915

Copyright, 1915, by
D. APPLETON AND COMPANY
Printed in the United States of America

CONTENTS

LIST OF ILLUSTRATIONS

Map of the Panama Canal Zone, Showing Hospitals of the Sanitary Department.

SANITATION
IN PANAMA

CHAPTER I
YELLOW FEVER AND THE DISCOVERIES OF ITS TRANSMISSION

Yellow fever for two hundred years before the Spanish-American War caused great loss of life and much destruction of wealth. Every few years portions of the United States would become infected with this disease. In the earlier part of this period the disease was more or less local. As the Mississippi valley became more thickly populated, the extent of the disease and the injury caused became very much augmented. The epidemic of 1878 was probably the deadliest and most extensive epidemic of yellow fever which ever affected the United States. In this epidemic over thirteen thousand people in the Mississippi valley alone lost their lives, and the loss of wealth is estimated at considerably more than one hundred millions of dollars.

It is very difficult to convey to a reader any idea of the conditions which exist during an epidemic of yellow fever. All business is entirely paralyzed, the quarantines not allowing any communication between the affected districts and those not affected. In an epidemic of any extent this means hundreds of local quarantines. Some idea of the condition of affairs can be obtained by picturing what would occur in any community if all the income of that community should entirely cease for six months. And this was the condition of business all over the Mississippi valley every time yellow fever gained entrance.

The population originally feared yellow fever on account of the poverty, suffering and business depression always caused by the quarantines which had to be enforced to prevent its spread, and in time people came to associate this idea of dread with yellow fever itself. When this disease was announced in a town, everybody left who could. The sick were frequently left without care, and often a great deal of cruelty and cowardice was shown. If a person escaped from an infected region and became sick with the disease, or sick from any other cause, he was generally treated as if he were a leper, and would often be left to starve or die on the roadside.

It requires continuously warm weather for the yellow-fever mosquito to breed in sufficient numbers to propagate yellow fever; therefore, this disease never became endemic in the United States. I mean by endemic, existing all the year round and over a number of years. The frosts of winter, wherever they occur, either destroy all the yellow-fever mosquitoes, or reduce their number below the point at which yellow fever could be propagated.

It was known in the United States that yellow fever was always brought somewhere from the littoral of either the Gulf of Mexico, or the Caribbean Sea, and the city of Havana, located on the northern coast of the island of Cuba, was known to be the center of this endemic area.

Yellow fever in 1898 was looked upon as the example of a filth disease, par excellence, and it was thought that if Havana were put in a proper state of cleanliness, it might cease to be the great point of infection for the United States. It was known that yellow fever had existed in the city of Havana continuously for one hundred and fifty years. It is interesting to note that the endemic infection of Havana occurred in 1762, when Havana was besieged and captured by American troops. I say American troops, because the expedition was largely composed of men from the present United States, then colonies of Great Britain. It is also interesting to note that this infection was supposed to have been brought by a vessel from Vera Cruz.

Yellow fever peculiarly affects shipping, and time and again ships in the harbor of Havana have had every living soul of their crew die from this disease, and these vessels would have to lie there for months until another crew could be obtained.

When we went to Havana in 1898 we knew no more of the sanitation of yellow fever than we had known a century before. The army which went to Santiago suffered as severely from yellow fever and other tropical diseases as any military expedition into the tropics had suffered before that time, and its death rate, had it remained, would have been just as high as was that of the French army of similar size, which was exterminated in the island of Haiti just one hundred years before.

A very deep impression was made upon me by the condition of our army at the end of two months’ campaigning in this tropical region. It was utterly used up and of no value whatever as a fighting machine. Fully four-fifths of the men were having fever. This small army of sixteen thousand men was as fine a body of soldiers when they landed at Siboney as could probably be gotten together, but after two months’ campaigning in this tropical jungle, and after several weeks of fever from which no one was free, their stamina and morale were completely gone. After the surrender of the Spanish garrison there was a complete let-down on our side. Everybody wanted to go home. No one could see any need of staying in Cuba, and every individual was perfectly certain that he would die if he remained there a month longer. Officers and men became nervous and hysterical. I commanded the base hospital at Siboney, and it was my disagreeable duty to select from day to day those who would have to remain. Many times every day the poor fellows, officers and men, would break down and cry when told that they could not leave on the next ship. I could form some idea of what it must have been among the French at Haiti when they knew that they could not get away, but had to stay and die.

Being immune to yellow fever, I made application to go with the troops that took possession of Havana. We arrived there in December, 1898. The military authorities concluded that this was the opportunity which the United States had been awaiting for the past two hundred years. Thinking that yellow fever was a filth disease, they believed that if we could get Havana clean enough, we could free it from yellow fever. It was felt that if we could eliminate Havana as a focus of infection, the United States would cease to be subject to epidemics. This meant so much to the United States, financially and otherwise, that the authorities determined to make all other efforts secondary to this sanitary effort.

The city was cleaned as well as it was possible to cleanse it. This remark applies as well to the private premises as to the public highways. Energetic and capable Army officers were placed at the head of various municipal departments, and these departments were thoroughly organized and made as efficient as possible. By the middle of the year 1900 all the city governments were perfectly organized, and were accomplishing all that it was possible for them to accomplish. I believe that Havana was cleaner than any other city had ever been up to that time.

The health regulations of the Sanitary Department, such as the isolation and care of yellow-fever patients, were thoroughly and carefully carried out. But in spite of all this work and care, yellow fever had been steadily growing worse ever since we had taken possession of the city, and in 1900 there were a greater number of cases than there had been for several years. The Cubans twitted us with the fact that all our cleaning up and expenditure not only had not bettered things, but had even made them worse. They called attention to the fact that the very cleanest and best kept portions of the city were by far the worst sufferers from yellow fever, and the evidence was so staringly before our eyes that we had to acknowledge the truth of what they said.

The health authorities were at their wits’ end. We evidently could not get rid of Havana as a focus of infection by any method we then knew.

A few years before this period, an Italian savant had announced in Brazil that he had discovered the organism which caused yellow fever. This organism was known as the bacillus icteroides of Sanarelli, and it was quite generally accepted that Sanarelli had proved this to be the causative agent in yellow fever.

Drs. Reed and Carroll had proved that the bacillus icteroides of Sanarelli was identical with the hog-cholera bacillus. They made this demonstration while comparing the bacillus X of Sternberg with the bacillus icteroides of Sanarelli. The work was carried on by them during the years 1897 and 1898, at the laboratory of the Army Medical Museum in Washington. The investigation was undertaken at the request of General Sternberg.

In 1899 our Public Health Service published the report of a board of medical officers who had been sent to Havana to investigate Sanarelli’s organism. This report made a great impression. Surgeon-General Wyman, in his letter transmitting the report says:

The findings of this Commission, verifying the discovery made by Sanarelli, and making still further advances than did Sanarelli himself by determining the specificity of the bacillus icteroides, and that the primary infection of yellow fever is received through the respiratory tract, in other words, verifying one discovery and making others of almost equal importance, at the same time eliminating incorrect theories, must be considered a notable achievement in medical science and one of the greatest practical value to the people of the United States and other countries infected, or liable to be infected by yellow fever.

In view of the widespread interest which the report will excite and the practical deductions to be drawn therefrom, I have respectfully to request authority to have the same printed.

The findings of this Commission were:

First. That the microörganism discovered by Professor Giuseppi Sanarelli, of the University of Bologna, Italy, and by him named “bacillus icteroides” is the cause of yellow fever.

Second. That yellow fever is naturally infectious to certain animals, the degree varying with the species; that in some of the rodents local infection is very quickly followed by blood infection, and that, while in dogs and rabbits there is no evidence of this subsequent invasion of the blood, monkeys react to the infection the same as man.

Third. That infection takes place by way of the respiratory tract, the primary colonization in this tract giving rise to the earlier manifestations of the disease.

Fourth. That in many cases, probably a majority, the primary infection, or colonization, in the lungs is followed by a “secondary infection,” or a secondary colonization in the blood of the patient. This secondary infection may be complicated by the coinstantaneous passage of other organisms into the blood, or this complication may arise during the last hours of life.

Fifth. There is no evidence to support the theory advanced by Professor Sanarelli that this disease is primarily a septicemia, inasmuch as cases do occur in which the bacillus icteroides cannot be found in the blood, or organs in which it might be deposited therefrom.

Sixth. That there exists no casual relationship between the bacillus X of Sternberg and this highly infectious disease; and that this bacillus X is frequently found in the intestinal contents of normal animals and of man, as well as in the urine and the bronchial secretion.

Seventh. That, so far as your Commission is aware, the bacillus icteroides has never been found in any body other than of one infected with yellow fever; and that whatever may be the cultural similarities between this and other microörganisms, it is characterized by a specificity which is distinctive.

Eighth. That the bacillus icteroides is very susceptible to the influences injurious to bacterial life, and that its ready control by the processes of disinfection, chemical and mechanical, is assured.

Ninth. That the bacillus icteroides produces in vitro as well as in vita a train of the most marked potency; and that, from our present knowledge, there exists a reasonable possibility of the ultimate production of an antiserum more potent than that of Professor Sanarelli.

About the same time an officer of the Public Health Service, Dr. H. R. Carter, was making in Mississippi his epoch-marking observations upon the extrinsic incubation of yellow fever. Measured by the results produced, this was one of the most important papers ever written. Yet as high an authority as the Surgeon-General of the Public Health Service expected the greatest results to flow from the conclusions reached by this Board, and did not notice the report from his subordinate concerning the extrinsic incubation of yellow fever. The conclusions of his Board turned out to be all wrong and useless as to results. The report of Carter turned out to be pure gold, and was one of the great steps in establishing the true method of the transmission of yellow fever. I do not say this in criticism. It is almost impossible for contemporaries to judge the true value of discoveries, or to give the proper position to the men of their own time who make these discoveries.

General George M. Sternberg, the then Surgeon-General of the Army, was one of the leading bacteriologists of the profession, and was also one of the best known authorities on yellow fever. He doubted the findings of this Board, and obtained authority from the Secretary of War to appoint a board of Army medical officers to investigate this same subject. He appointed on this now famous and immortal board Reed, Lazear, Carroll and Agramonte. They came to Havana, and spent several months in investigating Sanarelli’s organism. They proved beyond peradventure that it had no causative relation to yellow fever, and identified it as a well-recognized organism.

It is an interesting historical fact that one of the yellow-fever patients in whom the Board of Public Health Service found Sanarelli’s organism was a patient of mine. He was a soldier, Private Patrick Smith, Eighth Infantry, a non-immune living in an infected part of Havana, so that I thought that he ought to be reported as a suspect. The case continued nine days, long enough to convince me clinically that the disease was not yellow fever. The symptoms in a case of yellow fever dying on the ninth day are always so well marked that the diagnosis should not be in doubt. But the Board found Sanarelli’s organism, and being themselves convinced that this was the organism of yellow fever, they believed the case to be that disease. It shows the necessity in scientific matters of being on one’s guard, and of approaching investigation with an open mind.

The Army Board having satisfied themselves that Sanarelli’s organism bore no relation to yellow fever, but was simply the ordinary hog-cholera bacillus, turned their attention to other matters, though they were always working in relation to yellow fever. They spent a great deal of time in examining the intestinal flora in cases of recognized yellow fever, but could find nothing that seemed to have any relation to this disease in a causative sense.

Being at that time the health officer of the city of Havana, and in that capacity having charge of all cases of yellow fever which occurred in the city. I necessarily came in contact with this Board a great deal, and with its various members. I was naturally much interested in the work, and kept in very close touch with it. The Sanitary Department of Havana had a commission of medical men to whom all cases of yellow fever were referred for diagnosis. I was a member of this Commission, and Dr. Carlos Finlay, Dr. Antonio Albertini and Dr. John Guiteras were the other members. Each of us had had a very large practical experience with yellow fever. It is likely, therefore, that our Commission was as accurate in its diagnosis of this disease as it was possible for fallible doctors to be. Most of Dr. Reed’s experimental cases were seen and passed upon by this Commission. Dr. Reed requested us to do so, in order that the diagnosis of his cases might be upon the same footing as the diagnosis of the other cases occurring in the city of Havana.

Dr. Carlos Finlay, of Havana, the physician just mentioned as being a member of our Commission, had ever since the year 1881 been investigating, thinking of and writing about the relation of the mosquito to yellow fever. He had convinced himself that this insect was the means whereby the disease was conveyed from person to person. Others before Dr. Finlay’s time had referred to the possibility of this being the case, notably Dr. J. C. Nott, of Mobile, Alabama. In March, 1848, he published in the New Orleans Medical Journal an article in which he maintained that the spread of yellow fever could not be explained by the assumption of a diffusible miasm in the atmosphere. But Dr. Finlay had given more attention to this subject than anyone who had gone before him. He had written upon it constantly from the year 1881. His argument from the then known facts with regard to yellow fever, showing from these facts that it was probably the mosquito that conveyed this disease, was most beautiful and logical. But a still more beautiful piece of reasoning was the induction that it was the stegomyia mosquito, out of the six or seven hundred species of mosquitoes, that conveyed yellow fever.

Dr. Finlay, in the twenty years before we went to Havana, had done a great deal of experimenting on the human subject with regard to yellow fever. But he had not been successful in transmitting the disease. He had no means of knowing that it took the mosquito twelve days from the time when she swallowed the blood of a yellow-fever patient to become herself infectious. Not knowing this fact, it was perfectly natural for Dr. Finlay to use his mosquitoes upon his experimental cases within the first four or five days after they had bitten a yellow-fever patient. At any rate, in a large number of experimental bitings of the human subject he did not have a single case in which the evidence was conclusive that yellow fever had been conveyed by the mosquito. Reed says of Finlay: “To Dr. Carlos Finlay, of Havana, must be given, however, full credit for the theory of the propagation of yellow fever by means of the mosquito, which he proposed in a paper read before the Royal Academy in that city at its session on the 14th day of August, 1881.”

The Reed Board, after many months of inconclusive work in other directions, turned their attention to Dr. Finlay’s mosquito theory. Dr. Reed discussed the matter with Dr. Finlay a good deal before he commenced his mosquito work, and was thoroughly familiar with Dr. Finlay’s arguments and ideas on the subject. Indeed, we all knew Dr. Finlay well, but were rather inclined to make light of his ideas, and none more so than I. He and I met every day on the yellow-fever Commission above referred to, and it is probable that every day for more than a year we had more or less discussion on this subject.

Dr. Finlay is a most lovable man in character and personality, and no one could be constantly thrown with him as I was daily for several years without becoming warmly attached to him and forming the highest estimate of his scientific honesty and straightforwardness. Being very familiar with yellow fever, both historically and clinically, I was constantly bringing to his notice instances in the past which could not be accounted for on the mosquito theory. He, with the greatest ingenuity, was equally ready to explain how the mosquito theory could be turned so as to meet just this condition.

Dr. Finlay is still living in retirement and comfortable old age in the city of Havana. When the American forces were withdrawn from Cuba in 1902, Dr. Finlay succeeded me as health officer under the Cuban Government. He has since been retired on a pension by that Government. I called on him in Havana several years ago, and found him enjoying his more than eighty years of age, and the honors that were being heaped upon him. He is one of the few great men who has had his work recognized during his lifetime.

Dr. Reed got from Dr. Finlay the eggs from which he raised the mosquitoes used in his experimental work. Dr. Finlay says on page 1 of his “Agreement between the History of Yellow Fever and Its Transmission by the Culex Mosquito”: “The experiments made by Drs. Reed, Carroll, Agramonte and Lazear were started in June, 1900, with a brood hatched from eggs of the identical insect which at Dr. Lazear’s request I had handed to him. All the successful experiments have hitherto been made with that particular mosquito.”

Dr. Reed says in his paper, “The Etiology of Yellow Fever, Preliminary Note”: “We here desire to express our sincere thanks to Dr. Finlay who accorded us a most courteous interview and has gladly placed at our disposal his several publications relating to yellow fever, during the past nineteen years; and also for ova of the species of mosquito with which he had made his several inoculations. An important observation to be here recorded is that according to Finlay’s statement, thirty days prior to our visit, these ova had been deposited by a female just at the edge of the water in a small basin, whose contents had been allowed to slightly evaporate; so that these ova were at the time of our visit, entirely above contact with the water. Notwithstanding this long interval after deposition, they were promptly converted into the larval stage, after a short period, by raising the level of the water in the basin. With the mosquitoes thus obtained we had been able to conduct our experiments. Specimens of this mosquito forwarded to Mr. L. O. Howard, Entomologist, Department of Agriculture, Washington, D. C., were kindly identified as culex fasciatus—Fabr.”

CHAPTER II
THE EXPERIMENTS OF THE REED BOARD

After consultation, the Reed Board determined to experiment to see whether the mosquito really did convey yellow fever. But it was necessary to have a good deal of money and sufficient authority before starting in. The Board had come to Cuba for entirely different investigations, and had not been supplied with sufficient funds for these experiments. Fortunately for the cause of science and of humanity, we had as Governor-General of Cuba at that time General Leonard Wood, of the United States Army. General Wood had been educated as a physician, and had a very proper idea of the great advantages which would accrue to the world if we could establish the fact that yellow fever was conveyed by the mosquito, and his medical training made him a very competent judge as to the steps necessary to establish such fact.

General Wood during the whole course of the investigations took the greatest interest in the experiments, and assisted the Board in every way he could. Dr. Reed outlined to General Wood the course he expected to pursue, and General Wood was so convinced by Dr. Reed’s argument that he authorized the expenditure from Cuban funds of a sufficient sum and gave Dr. Reed ample powers as to the method of expenditure.

The Board then went to work in earnest along lines which seemed calculated to develop the facts in the matter. They started a laboratory at Camp Columbia, the American military station a short distance out of Havana. Here they bred their mosquitoes from eggs procured from Dr. Finlay, and here the first three experimental cases occurred. The first case was severe; the second case was that of Dr. Carroll, a member of the Board, and was well marked, and Dr. Lazear, another member of the Board, died of the disease. Dr. Lazear visited Las Animas Hospital and was bitten by the mosquito on September 13, 1900; was taken sick September 18th and died September 25th. Previously on August 16th, he had been experimentally bitten by a mosquito which had ten days before bitten a yellow-fever patient in the fifth day of the disease. We know now that ten days is too short a time for incubation in the mosquito, and the fifth day a period too late for the yellow-fever patient to be infectious.

Dr. Carroll was intentionally bitten. Dr. Lazear told me after he was taken sick, and a day or two before he died, that he recalled being bitten by a stegomyia three or four days before he was taken sick, and while he was at work at Las Animas, our yellow-fever hospital in Havana. He said that he had noticed the mosquito enough to recognize that it was a stegomyia, and had allowed it to fill and fly away without disturbing it. These three cases satisfied the Board that the stegomyia mosquito was the means of conveying yellow fever, but they determined that they would make such a demonstration of the matter that there could be no doubt in the mind of any reasonable person as to what had been proved.

With this idea in view they selected a spot a mile or more from the military camp, which was well isolated and had no habitations near it. They agreed that if they established an experimental station here and kept their patients in such a way that there was no possibility of their getting out and contracting the disease elsewhere, then the results obtained in this station would be due to measures taken there. They already had their stegomyia mosquitoes which they had reared from the eggs procured from Dr. Finlay. These mosquitoes they took to the hospitals in Havana, and allowed them to bite people sick with yellow fever. In the course of time the Board found that the mosquito to become infected with this disease must bite the sick human being within the first three days of his disease. This was a singular and unexpected phenomenon, and is explained in this way. The mosquito injects the yellow-fever parasite into the blood of the human being; these parasites at once commence ejecting toxins into the blood in which they are circulating; these toxins irritate the human cells with which the poisoned blood comes in contact and they begin to throw into the blood circulation antitoxins. By the end of the third day these antitoxins have become so concentrated in the blood that they always kill the yellow-fever parasite, and after the third day no yellow-fever parasites remain in the human body.

Yellow fever is a very fatal disease, and on the average kills the patient on the sixth or seventh day. Why then does death occur in yellow fever if on the average the patient lives to the sixth or seventh day, and yet always by the end of the third day the yellow-fever parasites have been routed and destroyed in the great battle which has taken place between them and the body cells?

Dr. Reed established this fact by finding that mosquitoes which had bitten a patient more than three days after the patient had developed yellow fever, did not convey the disease to the non-immune when he attempted to infect these non-immunes with such mosquitoes. On the other hand, he found that he was almost always able to give these non-immunes yellow fever when he used mosquitoes which had bitten the man sick with yellow fever within the first three days of his symptoms.

We have followed Dr. Reed now up to the point of his having infected mosquitoes and being ready to transmit the disease to non-immune human beings. A human being, in order that he may be liable to yellow fever, must be non-immune, and by immune I mean a person who either has had yellow fever, or has lived ten or more years in a locality where yellow fever prevails. An attack of yellow fever gives a great immunity to the disease, probably just as much as occurs in the case of smallpox. In practice, it is counted as absolute. In over two thousand cases of yellow fever which I have treated personally or seen in consultation, I have never seen a single case with a second attack, in which I saw the same individual in the first attack. I have seen several, however, who believed that they had had a previous attack, and I myself believe that I saw them in their second attack. I have by no means seen a quarter as many cases of smallpox as I have of yellow fever, yet I have seen more cases of second attacks of smallpox than I have of yellow fever. I feel confident, therefore, in stating that yellow fever gives fully as great immunity as does smallpox.

It is well known that in a yellow-fever endemic center such as was Havana during the nineteenth century native Havanese are not liable to yellow fever. They look upon their immunity as being absolute, and in my experience of fourteen years of life in such endemic centers I am inclined to accept their belief. The immunity of the native is explained by saying that he has probably had yellow fever in childhood when the disease was very mild, and that, at the time, it was overlooked and not recognized. This is the best explanation that, so far as I know, can be made of the facts in the case.

Certain it is that one of these endemic centers from which yellow fever has been banished for a number of years may have yellow fever as badly as a city in which it has never been endemic. Eighty years ago a native of Mobile, Alabama, or Pensacola, Florida, looked upon himself as being as immune to yellow fever as did the Havanese twenty years ago. But at the present time the native of either of these cities is just as liable to yellow fever as is the man from New York. This is explained by the fact that eighty years ago they had yellow fever so frequently in Mobile and Pensacola that all the natives had this disease in childhood. Within the last fifty years they have had it so infrequently that very few now living in those cities have had this disease.

Another phase of the same condition is seen in Ecuador. Guayaquil, the port of Ecuador, is located on Guayas River at sea level, not more than three degrees from the equator. Here yellow fever always prevails, and the native of Guayaquil is not liable to the disease and never has it. Quito, the capital of Ecuador, is situated about two hundred miles away, right on the equator, and on the great Andean plateau ten thousand feet above sea level. The stegomyia cannot breed at Quito, so that yellow fever has never occurred there. The native of Quito, therefore, has no immunity to yellow fever, and of this he is well aware. Guayaquil is the only seaport of Ecuador, and everyone leaving the country has to leave through this port. Hundreds of the natives of Quito have died of yellow fever contracted by passing through Guayaquil. The man from Quito dreads Guayaquil a great deal more than did the American in the early days fear Panama.

Dr. Reed, therefore, to make his experiments of any value, had to get human beings who had neither suffered from yellow fever itself, nor had lived long enough in an endemic center to acquire immunity. Havana for a number of years had received a considerable Spanish immigration. At the time to which I refer, it amounted to about twenty thousand a year. These immigrants believed that they were going to have yellow fever, and though they knew that a considerable number of them must succumb during the process, they were anxious to have the disease and be done with it. There was a very general belief among the Spaniards in Havana that a person with what they called “thin blood” as contra-distinguished from a robust, plethoric, full-blooded person, was much more likely to recover from yellow fever. They tried, therefore, with their newly arrived friends, relatives and dependents from Spain to bring about this condition of their blood. They kept them confined in a darkened room and fed them on a very limited diet, and certainly succeeded in rapidly reducing the strong, florid, robust Gallego to a very marked condition of anemia and debility. The Spaniard believed that he thus saved many lives. I was convinced that he thus killed a good many of his friends and dependents.

The newly arrived Spaniard, as soon as he had had yellow fever and could present a certificate of immunity, could command double the wages that he could get before he had the disease. So that when Dr. Reed proposed to some of these men that they should go out to his camp, have a mild case of yellow fever, be well cared for and when recovered be given by him a certificate of immunity, he found no difficulty in getting volunteers, and when, in addition to that, he promised each man who had the disease a bonus of two hundred and fifty dollars, the service became exceedingly popular.

Dr. Reed had prepared, as I have above mentioned, a very comfortable camp at an isolated point near Camp Columbia, well separated from all other dwellings. This camp was kept under military guard, so that no one could come and go without Dr. Reed’s knowledge. Here he placed his non-immune volunteer Spaniards whom he had gotten from Havana, and kept them under observation for two weeks, taking their temperatures every day so as to be sure that they had not contracted yellow fever before they went out to the camp.

At this point he made another important discovery in the mode of yellow-fever propagation. He found that the mosquito herself had to wait from ten to fifteen days after she had bitten a man sick with yellow fever before she herself conveyed the disease. He found that the mosquito for the first week or ten days after she had bitten the yellow-fever patient was entirely harmless though she fed freely on non-immunes. But after the twelfth or fourteenth day she would give the disease to every non-immune whom she bit. I have often seen the non-immune doctors and nurses at Las Animas Hospital put their hands in the jars where infected mosquitoes were kept during the first seven days of their infection and allow them to draw their fill of blood, for the purpose of feeding them, but they would not think of doing this after the seventh or eighth day. Two of these nurses afterwards contracted yellow fever from allowing mosquitoes to bite them after the twelfth day, and one of them, Miss Mass, died from the disease so contracted.

Dr. Carlos Finlay, in his many experiments on the human being, was unaware of these two facts with regard to the transmission of yellow fever: first, that the mosquito could only become infected by biting a human being within the first three days of his disease; and second, that she could only become infectious, that is, transmit the disease, when some twelve or fourteen days had passed since she had bitten the sick man. Dr. Finlay put a great many of his mosquitoes to the sick man after the third day, and in no case did he apply his mosquito to the non-immune twelve or fourteen days after she had bitten the infected person.

Dr. Henry R. Carter had published a paper on certain observations of his made during the epidemic of 1898 in the neighborhood of Jackson, Mississippi. It had long been known to men practically familiar with yellow fever that, in general, when you took a patient suffering from yellow fever into a house where yellow fever had not before existed, the people in that house did not at once develop the fever. We explained this by stating that it was due to the fact that the germs of yellow fever went from the patient to favorable grounds for development about the house, and there underwent some development which enabled them to produce the disease in non-immune man. We thought that the dirtier and more unhygienic were the conditions of the house, the more favorable were the conditions for the further development of the germs. Dr. Carter recorded a number of cases where the houses were isolated and the conditions favorable for making the observations, and found that the average time from the introduction of a yellow-fever patient into a house until the first case of yellow fever was contracted in that house, was about seventeen days. These observations were published to the world.

Dr. Reed was greatly impressed by this publication of Dr. Carter’s. He reasoned that if it were the mosquito which transmitted the disease, this period of extrinsic incubation must be due to a period of incubation in the mosquito. He says:

We were also much impressed by the valuable observations made at Orwood and Taylor, Mississippi, during the year 1898 by Surgeon Henry R. Carter, U. S. Marine Hospital Service, “A Note on the Interval between Infecting and Secondary Cases of Yellow Fever, etc.” (Reprint from New Orleans Medical Journal, May, 1900.) We do not believe that sufficient importance has been accorded these painstaking and valuable data. We observe that the members of the yellow-fever commission of the Liverpool School of Tropical Medicine, Doctors Surham and Meyers, to whom we had the pleasure of submitting Carter’s observations, have been equally impressed by their importance. (British Medical Journal, Sept. 8, 1900, pp. 656-70.)

The circumstances under which Carter worked were favorable for recording with considerable accuracy the interval between the time of arrival of infecting cases in isolated farmhouses and the occurrence of secondary cases in these houses. According to Carter, “the period from the first (infecting) case to the first group of cases infected at these houses, is generally from two to three weeks.”

The house having now become infected, susceptible individuals thereafter visiting the houses for a few hours, fall sick with the disease in the usual period of incubation, one to seven days.

Other observations made by us since our arrival confirmed Carter’s conclusions, thus pointing, as it seemed to us, to the presence of an intermediate host, such as the mosquito, which having taken the parasite into the stomach, soon after the entrance of the patient into the non-infected house, was able, after a certain interval, to reconvey the infecting agent to other individuals, thereby converting a non-infected house into an “infected” house. This interval would appear to be from nine to sixteen days (allowing for the period of incubation) which agrees fairly closely with the time required for the passage of the malarial parasite from the stomach of the mosquito to its salivary glands.

In view of the foregoing observations we concluded to test the theory of Finlay on human beings.

Dr. Reed had, however, been working for some time before he came to these conclusions. His first nine cases bitten between August 11 and August 25, were all unsuccessful. The next two, bitten on August 27 and 31, were positive and were well-marked cases of yellow fever.

But Dr. Reed’s work was now brought to a stand-still. He found that all his Spaniards were deserting, and that he could get no more for love or money to come to the camp. The work from being much sought had become very unpopular. For some time he was unable to find any good reason for this. The story told in Havana was that the American soldiers, who were doing the guard duty for the camp, had found an old lime kiln in the lower part of the grounds. In this kiln they had placed a lot of bleached old bones, and here they would take the newly arrived Spaniard and darkly insinuate that these were the bones of their predecessors in Dr. Reed’s camp, and that if they did not leave before they were bitten by Dr. Reed’s mosquitoes, their bones would soon be bleaching in the same place. It was useless for Dr. Reed to argue and explain. This ocular evidence was too strong for any argument by word of mouth, and Dr. Reed had to give it up.

Our soldiers had seen that the disease was very mild; that the patients while they were in camp had the very best of high living and a mighty good time, and when they left, were presented with a gratification of two hundred and fifty dollars in shining gold coin. They concluded that this was too good for Gallegos, and belonged of right to natural-born Americans. When the Spaniards had decamped, our men came forward and volunteered. Dr. Reed accepted them, and the work went forward.

CHAPTER III
THE DISCOVERIES OF THE REED BOARD

Dr. Reed wished to make his demonstrations as convincing and spectacular as possible. It was an entirely new idea, and his conclusions excited a great deal of adverse comment and criticism. This theory was so contrary to what most men thought had been their practical experience that it was received with scant consideration.

He had a small frame house built, fourteen by twenty feet, well screened-in with wire netting, so that mosquitoes could not get in or out. This building he had divided into two compartments by a partition extending down the center, made of wire netting, and it was known as the infected mosquito building. It was well ventilated. Most persons at this time believed that in some way the air conveyed yellow fever. Dr. Reed wished to show that this was not the case.

He put two non-immunes in this building, one in each room. These two men breathed exactly the same air, and had exactly the same surroundings, with one single exception which I will in a moment point out. But they were entirely separated by the wire netting. He let them live and sleep in these rooms for several days, so as to demonstrate that there was no yellow-fever infection in the building. He then put fifteen infected stegomyia in one of the rooms; left the man in this room for thirty minutes, announcing that the room was now infected. He took the man out of this infected room, but left in the other room two men on the other side of the wire netting. He stated that the man who had stayed thirty minutes in the infected room would come down with yellow fever within three or four days, and that the other men, who were only separated from him by wire netting, and who breathed and were surrounded by exactly the same air, would not get sick.

He explained that the only difference between the two rooms was that in the infected room, infection had been brought about by liberating there fifteen stegomyia mosquitoes which had previously bitten patients sick of yellow fever. The man from the infected room was on the afternoon of the same day again placed in this room for twenty minutes, and on the following day he was a third time put in the room for fifteen minutes. On the first visit he was bitten by seven mosquitoes; on the second, by five; on the third, by three. At the end of the fourth (Christmas) day, Reed showed the man from the infected room down with yellow fever, and the men who had lived and slept in the other room, separated only by wire netting, perfectly well. He called attention to the fact that the only difference in the exposure of these men was that the sick man had been in a room for thirty minutes, with fifteen infected stegomyia mosquitoes. He claimed that this was a demonstration that the female stegomyia mosquito could transmit yellow fever, and that the atmosphere alone could not. Many of the visitors to Dr. Reed’s camp were clinically familiar with this disease, and the case was sufficiently marked to be easily recognized by all as being a case of yellow fever.

Dr. Reed then announced that he would disinfect the room so that it would no longer give yellow fever. When it was prepared, he again placed a non-immune in each room, left them there for several days, and they remained perfectly well. He explained that he disinfected the room by simply catching all the stegomyia mosquitoes which he had formerly liberated in the room.

This demonstration made a very profound impression. Many, however, still urged that while it was evident that the female stegomyia mosquito could convey yellow fever, it was equally evident from the history of epidemics of this disease that it could be and was generally conveyed in other ways, such as soiled clothing, bedding, the bodies of yellow-fever dead, persons sick of the disease, etc.

Dr. Reed had a small house built, made almost air-tight and with scarcely any ventilation. This building was known as the infected-clothing building, and was purposely so constructed as to exclude anything like efficient ventilation. It was placed on the opposite side of a small valley, about eighty yards from the infected mosquito building, and they were both about seventy-five yards distant from the camp proper. Both houses were provided with wire screen windows and double screen doors, so that mosquitoes could be kept without or within the building, as the experimenter might desire.

In this building he placed material obtained from Las Animas, the yellow-fever hospital of the Health Department of Havana; mattresses on which yellow-fever patients had died, soiled by their excreta and discharges; sheets, pillows and pillow-cases stained with black vomit; the pajamas which patients had worn at the time of their death. It was Dr. Reed’s desire to have this material infected if it were possible to become infected in this way. Dr. John W. Ross, the superintendent of Las Animas Hospital, therefore gave the matter his personal attention, saw to the packing of this material in chests for transportation to Camp Lazear, and before the chests were closed, had basins of black vomit and other excreta from yellow-fever patients poured over the contents of the chest. If there were any possibility of such material becoming infected, infection certainly would have followed such procedure.

Dr. Reed had this material opened up and spread out in the close room I have described. He called for volunteers to sleep in this room. Dr. R. P. Cook of the Army, and several soldiers quickly responded. These men put on the pajamas soiled as described, and slept on the mattresses and bed clothing soiled beyond description. For a period of twenty days they spent the nights in this building, but for the sake of general health were allowed to go out during the day. All the men remained perfectly well, and no case of yellow fever was developed from such exposure.

This set of experiments was generally accepted as proving that yellow fever was conveyed from man to man by the mosquito alone, and that it was not transmitted in any other way. A great many persons, however, were still skeptical. The experimental camp had been named “Lazear” in memory of Dr. Lazear, a member of the Board, who had died a few months before of yellow fever, contracted while prosecuting this work.

The Board then took the blood of a yellow-fever patient in the first three days of his sickness, and injected it with a hypodermic syringe into a non-immune. He promptly developed yellow fever. This proved that the blood of a patient suffering from this disease could transmit yellow fever without passing through the body of the mosquito. From this experiment of injecting the blood directly from one person into another it was argued that it might not be a yellow-fever parasite that was injected, but a toxin.

The Board then took the blood within the first three days of sickness from this second patient who had been given his disease from the blood of the first patient, and injected it into a third patient. This third patient developed the disease at the proper time. This experiment demonstrated that the virus so conveyed was capable of multiplying; that it was a living germ and not merely a toxin or chemical body which transmitted the disease.

The Board then took the blood of a patient collected in the first three days of his sickness, and passed it through a Pasteur filter so fine that it would stop any particle large enough to be seen with a microscope of the highest power. This blood when injected into a non-immune still gave yellow fever. This demonstrated that the parasite was sub-microscopic; that is, too small to be seen by a microscope of even the highest power.

They then took the blood of a yellow-fever patient within the first three days of his disease, heated it to 55° C., and injected it into a non-immune. The non-immune did not develop yellow fever. This was repeated three times. This experiment proved that the living parasite in the blood of the yellow-fever patient was killed by being raised to a temperature of 55° C.

The conclusions announced by the Board were as follows:

That yellow fever is conveyed from man to man only by the bite of the female stegomyia mosquito, and that this mosquito, to become infected, must suck the blood of the yellow-fever patient within the first three days of his disease.

That after biting the patient, twelve to twenty days must elapse before she herself is able to convey the infection. This period is known as the period of extrinsic incubation. Extrinsic incubation in Havana was found to be considerably longer during the cool months of winter than during the warm period of summer.

That after the non-immune human being had been bitten by the infected stegomyia mosquito, an incubation period of from three to six days elapsed before the man began to show symptoms of yellow fever. The shortest period of incubation in Dr. Reed’s cases was two hours less than three days, and the longest period, two hours more than six days.

That the blood, taken at the proper time and injected into a non-immune, would also cause yellow fever; that the disease was caused by a parasite, and that the parasite was sub-microscopic.

These discoveries have been of enormous benefit to mankind, and upon them has been based the sanitary work against yellow fever which has been so successful. At first blush, however, it was not evident to what extent it would be of practical use to us.

CHAPTER IV
THE SANITARY BOARD OF HAVANA

At this time, February, 1901, I was health officer of the city of Havana. The efforts of the Department had been concentrated for more than two years previous upon controlling yellow fever in that city. Not only had we met with no success, but yellow fever was actually worse than when we commenced work. Ample funds and power had been given us by General Wood, the military governor, and we had by far the best and most efficient sanitary organization of whose existence, either before or since that time, I have any knowledge.

When the work of the Reed Board began to point to the mosquito as the conveyor of yellow fever, the Sanitary Department of Havana was at its wits’ end and was glad to receive this discovery as a means of possible help. I, as health officer of Havana, had nothing to do with the work of the Reed Board in any way whatever, except that I was a very interested spectator and kept in close touch with the work as it developed. We assisted the Board in every way that we could. All the hospitals in the city were under our control, so that we were enabled to furnish them ample clinical material.

Neither the Reed Board nor any of its members had anything to do with the practical working out of the methods whereby their theory was demonstrated, and by means of which yellow fever was finally eliminated from Havana. These methods were first originated and worked out by the Sanitary Department of Havana during the year 1901. They have since been copied and successfully applied in many parts of the world where yellow fever formerly prevailed.

Dr. Finlay, in a reprint from the Journal of the American Medical Association, April 19, 1902, says:

The final confirmation of the rôle which appertains to the culex mosquito deso (now included in the genus stegomyia of Theobald) in the transmission of yellow fever, has now been sanctioned by the experiments of Drs. Reed, Carroll, Agramonte and the lamented Dr. Lazear, at Quemados de Marianao, during the winter of 1900, and afterwards by those of Dr. Guiteras at the Experimental Station of Las Animas, last summer, and finally by the splendid practical results obtained by the Chief Sanitary Officer of Havana, Major W. C. Gorgas, during the epidemic year which has just been completed. With those facts and the ones which I had gathered in former years, it is now possible to determine with some degree of precision the conditions which are necessary in order that yellow fever may develop in an epidemic form in a given locality, not too highly situated above the sea level and where temperatures between 25° and 35° C. (77° and 95° F.) either temporarily or habitually prevail.

Dr. Reed and I discussed on several occasions the possibility of making practical application of his discoveries. It did not seem to us possible to destroy the adult mosquito in sufficient numbers to be of any practical use. And we were not sufficiently familiar at that time with the life history of the mosquito to think of any other way in which the subject could be approached with a fair prospect of success.

We, of the Sanitary Department, after a great deal of discussion and thought given to the matter, decided that we should adopt all measures that seemed likely to be useful, being guided in our plans principally by the life history of the mosquito.

After the first two cases—in all some twenty-six—all the Board’s cases had been very light. We concluded, therefore, that our strongest measure would be vaccination; that is, to have an infected mosquito bite a non-immune and give him a light case. If this proved as successful as had vaccination in smallpox, we could see that this measure alone would entirely protect against yellow fever, just as had vaccination against smallpox. We consulted the military governor, General Wood, on the subject, and he agreed to let us try it as one of the several preventive measures which we were putting into effect against yellow fever.

We announced that we were ready at Las Animas Hospital to immunize against this disease anyone who wished to be treated in this way. There was no lack of applicants. This was in February, 1901. Most of the work of the Army Board had been done during the preceding fall, and at this time we had only one infected mosquito left, which had been given us by Dr. Reed. This old lady was a veteran in every sense. She had given several people yellow fever, but her greatest claim to celebrity was the fact that it had been fifty-seven days between the first case of fever and the last one which she had given.

The weather is cool in Havana during January, February and March, so that the stegomyia under ordinary conditions become quite sluggish in their movements and a great many die. Mosquitoes decrease so much during these months that yellow fever becomes more or less rare, and it was very difficult for us to infect our mosquitoes. While for one hundred and forty years there had never been a single month in which there had not been some reported case of yellow fever in Havana, still only a very small proportion of these cases was recognized during the first three days, and it must be remembered that a mosquito has to bite within that period of the disease in man to become infected. We were, therefore, keeping our only infected mosquito with a great deal of care and tenderness, knowing that we had to depend upon her to start our vaccination work.

In all Havana there is probably not a single fireplace or other means of artificial heat, so we sent to the United States and imported an oil-stove wherewith to keep her ladyship’s room always at summer temperature. Her home was a large glass jar on a table in the center of a sunshiny room. In this jar was hung a lump of white sugar on which she fed when hungry, and to this was added now and then a small piece of banana. A small vessel containing water was also kept in the jar. In order that she might have a plentiful supply of fresh air, the glass top was not placed upon the jar, but a sleeve of mosquito-netting was tied over its top.

Within the last fifteen years a great deal of study has been given to mosquito life. It is now known that there are some seven hundred different species of mosquitoes; that in all species of mosquitoes the natural food is the various vegetable juices. In all species the female has to have a feed of blood before she can lay eggs. Blood does not seem to be necessary for life, but merely stimulates the function of ovulation. In order that the female may get this blood, she is furnished with biting apparatus not possessed by the male. The male never bites, not being physically able to do so. The female stegomyia, therefore, is alone concerned in the transmission of yellow fever.

Las Animas Hospital being the yellow-fever hospital for the city of Havana was a center of attraction for most of the doctors of the Health Department. Dr. John W. Ross, Dr. John Guiteras and myself were at this hospital almost every day. Dr. Guiteras had charge of the vaccination work and of the laboratory where the mosquitoes for this work were being bred. Our lady mosquito was therefore directly under his charge. She had given so many people yellow fever and was therefore so valuable for our prospective work that we all when at the hospital would drop in to see how she was coming along and to pay our respects.

One morning about daylight I got a message stating that her ladyship was in a most critical and desperate plight, as some time during the night she had gotten her wing caught in a mesh of the mosquito netting, and had struggled to free herself for so long a time that when she was discovered by the attendant in the morning, she was almost dead. I rapidly dressed and hurried to the hospital. Similar messages had been sent to Dr. Ross and Dr. Guiteras. We found her condition even worse than had been represented. Two or three of the doctors on the staff of the hospital had been promptly called in, and the services of several of our trained nurses had been likewise obtained. Her wing had been gently liberated from the mesh of the netting, and her ladyship laid upon a soft bed of cotton batting. The oil-stove was started up, and the room brought to a very hot summer temperature, but it was all of no avail. She finally ceased to kick about nine o’clock in the morning, and died with a larger attendance of doctors and nurses around her table than had ever been present around the deathbed of any mere human in the city of Havana.

This account may sound somewhat exaggerated, but the scene still comes back to my mind’s eye very vividly, how earnest and serious we all were. A half-dozen of the leading practitioners of Havana were sitting around the deathbed of this mosquito, looking and feeling exceedingly mournful and depressed. And it was a very heavy blow to the Health Department of Havana. It was well on into the summer, the month of July, before we succeeded in getting another infected mosquito, and in proceeding with our vaccination work. Finally, we succeeded in infecting several mosquitoes, and bit with these mosquitoes sixteen persons, of whom eight developed the disease.

Much to our alarm, several of these cases developed very violent symptoms, much more so than had occurred in any of the cases of the Army Board, with the exception of Lazear and Carroll. Three of these eight positive cases vaccinated by Dr. Guiteras died; one of those who died was a Miss Maas, a trained nurse from the United States, who requested to be allowed to get immunity in this way. Why our cases should have been so severe, and all of the cases of the Board so mild, no one has attempted to explain. It is a fact that during the hot summer weather the extrinsic period of incubation in the mosquito, that is, the time after which the mosquito bites the man sick with yellow fever until she herself is able to convey the disease, is considerably shorter than the same period during the cool winter months, this period in the summer months being from twelve to fourteen days, and in the winter months, from fifteen to twenty days. I am inclined to think that there is probably the same difference in the virulence of the infection developed by the mosquito in the hot summer months, and in the cool winter months.

This experience demonstrated to us most forcibly that vaccination could not take any prominent part in our preventive measures against yellow fever. While Dr. Guiteras was going on with his preparatory work at Las Animas and getting ready for his vaccinations, he invited to the hospital some fifteen or twenty members of the International Sanitary Congress who had expressed themselves as being particularly skeptical with regard to the mosquito theory of the transmission of yellow fever. This Congress assembled in Havana during the month of February, 1902. The laboratory at Las Animas was the room I have just described as being the home of the mosquito known as “Her Ladyship.” It was carefully screened with wire netting at all the windows, and the single door was protected by a vestibule which itself had double doors. This vestibule was built upon a platform some four feet above the ground and just outside the door of the laboratory. The visitors pretty well filled the small room. Dr. Guiteras started at one end of his laboratory, explaining that in this jar he had the eggs of the stegomyia mosquito, and invited his visitors to examine them; in the next jar, the larvæ; in the next, the pupæ; in the next, the young mosquito just born, and in the last jar, the mosquitoes which had passed their period of extrinsic incubation and were now ready to convey yellow fever.

While handling this jar, the sleeve of mosquito-netting accidentally slipped off, and a dozen or more mosquitoes soared toward the ceiling of the room. Our visitors stood for a moment dumfounded, open-mouthed and wide-eyed. Then each one of the twenty, at the same moment, made a rush for the door. The vestibule was small and would hold only about four persons, so that the pressure from behind toppled it over onto the ground four feet below, and in a moment, there were some twenty gentlemen in a pile on the ground struggling to get as far as possible from these deadly lady mosquitoes.

Dr. Guiteras afterwards assured us that his mosquitoes had never bitten a sick man and were not infected; that he was only demonstrating the processes of mosquito-breeding and infection that would have to be carried out in the vaccination process. Our visitors laughingly acknowledged that, at any rate, their subconscious selves had been convinced of the correctness of the theory of the mosquito transmission of yellow fever.

CHAPTER V
SANITARY WORK AT HAVANA

The Army Board had demonstrated that the mosquito, to become infected, had always to bite some patient with yellow fever within the first three days of his disease. It was evident, therefore, that if we could prevent this being done in every case of yellow fever in Havana, the disease would disappear. This measure alone would be sufficient for eliminating yellow fever.

To accomplish this we required all cases of yellow fever in the city to be reported to the central office of the Health Department. They were at once seen by the official diagnosis commission, and if pronounced yellow fever, were at once moved to Las Animas Hospital in a carefully screened ambulance and placed in screened wards. The routine at Las Animas Hospital precluded the possibility of any mosquitoes biting the patient. Most of the Americans, and in fact patients of all classes, preferred to go to Las Animas. Under Dr. Ross’s care the hospital soon obtained the reputation of saving more yellow-fever patients than could be done at the other hospitals, or at their homes. This reputation was justly acquired. The statistics of this hospital amply bore out the reputation which public opinion gave it. If the patient elected, he could stay in his own home, the room or rooms to be screened were agreed upon, a skilled force of carpenters were sent by the central sanitary office, who thoroughly and carefully screened the designated apartments. Only one point of exit and entrance was left, and this was protected by a vestibule and double door. A number of squads of carpenters, each furnished with its own wagon loaded with the necessary wire netting, lumber, and other material, were always on duty, so that usually within an hour after notice came to the central office night or day, the patient was either removed to the hospital or was being screened at his own home.

To see that sanitary regulations were carried out and that only authorized persons were admitted within the screened quarters of the patient, an officer of the Sanitary Department was always on duty. He sat in the vestibule and required that one door should be closed always before the second was opened. He was changed every eight hours, that is, he was on duty only eight hours in each twenty-four. We soon found that this method could not be carried out in its entirety; that it was the exception that we could get hold of a patient during his initial chill. Generally the patient had been sick one or two days before he came under our observation.

It was evident, therefore, that a number of mosquitoes might have bitten him before he was discovered and cared for. As it would be twelve or fourteen days before these mosquitoes would become infectious, we had plenty of time to attend to them. From the known habits of the stegomyia mosquito we did not think they would leave the house in which they had become infected, though in an individual case this might occur, and a mosquito wander into a contiguous house.

Stegomyia Squad. Havana.

Screened Water Barrel. Havana.

To meet this condition of affairs, as soon as the case was concluded, the house in which the patient had been sick and all the contiguous houses were fumigated with such material as would kill the mosquitoes. In order that the fumigation might be effective the house had to be carefully gone over and all cracks and crevices stopped, so as to make the building as nearly air-tight as in the nature of things it could be made. This was a very laborious process and required care and expert supervision. Most of the stopping of crevices was done with paper and paste. Sulphur is probably the most effective substance in killing the mosquito. The rolled sulphur was used at the rate of about a pound to the thousand cubic feet of space to be fumigated. We generally used the Dutch oven placed in a box of sand or vessel of water, so that in case of a leak, or in case of the oven’s getting too hot, the floor would not catch on fire. With a large force of ignorant men engaged in this work constant watchfulness has to be used to see that fires do not occur. The proper amount of sulphur is placed in the Dutch oven, a little alcohol poured over the sulphur, and a match applied. The sulphur will burn for three or four hours, and will produce very dense fumes which will fill the building and kill all the mosquitoes. The fumes of sulphur in a building which has been well prepared will kill not only all mosquitoes, but all insect and animal life, and is by far the best material to use for this purpose. It is generally somewhat difficult to start the sulphur burning with alcohol alone, and I have noticed that the men got in the habit of using an ounce or two of pyrethrum placed on top of the sulphur for the purpose of starting the fire. The pyrethrum was moistened with the alcohol and would burn for a considerable time after the alcohol was consumed, in almost every instance starting the sulphur burning.

The fumes of sulphur will tarnish gilt metals of all kinds, and injure most light-colored fabrics. This occurs particularly where the air is heavily charged with moisture. In cases in which sulphur was likely to do damage, we used pyrethrum powder. This powder does not tarnish or injure fabrics of any kind. The building must be prepared in the same way as for sulphur, and the vessel in which the pyrethrum is burned must be arranged as above described for sulphur. The fumes of pyrethrum do not generally kill the mosquito, but simply intoxicate her. In the course of time she revives and eventually entirely recovers. For this reason the building should be opened up within a couple of hours after the burning of the pyrethrum, and all mosquitoes carefully gathered and burned.

In almost all dwellings of the better class of tenants there are fixtures and fabrics which will be injured by the fumes of sulphur. Therefore, in this class of buildings we generally used pyrethrum. For fumigating in this same class of buildings where pyrethrum was used we found a mixture of camphor and carbolic acid, one part of camphor to three of carbolic acid, very useful. This should be placed in a tin dish and vaporized with a spirit lamp. The same procedure should be observed as a precaution against fire as is taken with sulphur. The mixture when vaporized gives off dense white fumes which kill the mosquito. Generally, where care has to be taken for fear of injuring fixtures and fabrics, this mixture is preferable to pyrethrum. Pyrethrum should be used at the rate of one pound to the thousand cubic feet, and the camphor mixture at the rate of an ounce for the same space.

In Havana we had to deal with cigar manufactories and tobacco storehouses on a large scale. Here we could use neither sulphur, pyrethrum, nor the camphor mixture, as they all affected the delicate flavor of the tobacco. At first we used to move all tobacco out of a building to be fumigated. This was very laborious and added largely to the cost of fumigation and also tended to drive out from the building the infected mosquitoes before they had been reached by fumigation. Mr. Joseph Le Prince, who was in charge of this work, after much experimenting found that the fumes from tobacco stems did not hurt the flavor of tobacco, and were almost as deadly to the mosquito as was sulphur. We could therefore fumigate with this material buildings where tobacco was stored without injury to the tobacco. The stems were a waste product in cigar manufacturing, and could be obtained in large quantities at little cost. They should be used at the rate of two pounds to the thousand cubic feet, and with the same precautions against fire as are taken in other cases.

Formalin we found useless. It has apparently little effect upon insect life.

From our general knowledge of the life history of all species of mosquitoes, we knew they had to spend eight or nine days in a larval stage, and that while in this larval stage they lived in water. Therefore, collections of water were necessary for the development of the mosquito. The stegomyia mosquito we knew preferred clear, clean water, such as is supplied by the various collections of rain water needed for domestic purposes. The city of Havana had pipe water over only a small portion of its area. By far the larger portion of the population obtained its water supply from rain water stored in cisterns, tanks and receptacles of all kinds. We resolved to stop mosquito-breeding in all such places.

The city was divided into twenty inspection districts, each district under the charge of a sanitary inspector. This inspector was required to get around to each house in his district once a month and make a careful inspection with regard to mosquito-breeding, and report to the central office on a printed blank the conditions found. If this report indicated that the condition of the premises amounted to a sanitary nuisance, the householder was proceeded against. An order had been promulgated making it a sanitary nuisance for any householder to have mosquito larvæ on his premises. The health officer was given authority to impose a fine for such nuisance; the fine was collected by the Cuban courts, and the proceeds of the fine deposited in the Cuban treasury. The health officer had authority to remit the fine at any stage of the proceedings. In practice, it came about that the whole matter was settled in the Sanitary Department. We employed a lawyer to whom cases of fines were referred. When a householder was reported by the sanitary inspector as having larvæ on his premises, he was notified that under the sanitary ordinance he was fined five dollars for having this nuisance on his premises, but that if the nuisance were abated, the fine would be remitted. This usually brought the man promptly to the office with the statement that the nuisance had been abated. An inspector was sent around, and if the householder’s statement was found to be correct, the fine was remitted.

In a certain number of cases this notice caused no action on the part of the householder. In these cases the fine was sent to the judge of the district for collection by him. In the few cases in which the first notice had not brought the householder to terms, this action by the court did. If he reported that he had abated the nuisance and the inspector when sent to investigate found this to be the case, the fine was withdrawn. In this way we did very little fining. Out of about twenty-five hundred fines levied in the last nine months of 1901, only fifty were finally imposed and deposited in the treasury.

The Sanitary Department was said to be decidedly the most popular of the American departments with the Cubans, and it was this very power of assessing and remitting fines that was the principal cause of our popularity. The Cuban had been accustomed to looking upon laws and ordinances as devices for filling the pockets of the officials, and fines as the legitimate perquisites of those officials. When a fine was remitted, he looked upon it as a personal present from the pocket of the chief sanitary officer to himself, and was grateful accordingly. Why the chief sanitary officer should take so great an interest in mosquito larvæ he could not comprehend. But that officer evidently did take a most decided interest in the matter, and had he not demonstrated his friendship by taking five dollars, which was as good as in his pocket, and giving it to him, the offender? His loyalty was appealed to and generally he remained ever afterwards the friend of the Department.

Cisterns, barrels and receptacles for containing and storing rain water for drinking and domestic purposes were absolutely necessary in the case of the larger part of the population. It was necessary that we prepare these receptacles so that they could not breed mosquitoes. If it were arranged so that mosquitoes could not lay their eggs on the surface of the water, this object would be accomplished. It was therefore provided that all receptacles should be covered in such a manner that mosquitoes could not have access to them. The tops were covered, a small hole being left in the top by means of which water could enter. This hole was covered with wire netting, and a spigot was placed in the bottom whereby the water could be drawn off. This was done at public expense. At the central office squads of carpenters with material loaded in wagons were always on hand to go out for this work. If the sanitary inspector reported that such work was necessary, it was immediately attended to by one of these squads.

For carrying into execution the orders pertaining to mosquito work the city was divided into eight districts, each district in charge of a mosquito inspector. A great deal of stegomyia breeding went on in the interior of the dwellings. Every family had an earthen vessel in which drinking-water was kept for daily use. This always had larvæ in it. It was the inspector’s duty to empty this vessel, point out the larvæ to the housekeeper, and explain that if the vessel were emptied once a day and the larvæ washed out, mosquito development could not occur. All sorts of vessels in a house which might contain water had to be considered as possible breeding-places for mosquitoes. Every housekeeper in Havana, when we started work there, had a number of breeding-places for mosquitoes in her domestic establishment. Among these may be mentioned flower-pots in which a little too much water had been used; cans filled with water, in which the legs of tables had been placed as a protection against ants, etc.

Each mosquito inspector had with him five men, and one of these men carried a sufficient amount of oil to pour upon any pools or puddles about the premises that might need oiling. They picked up old bottles and cans which might contain water and become breeding-places, and generally looked after the yards. The district inspector, at the same time, made a general report on the premises in writing, and on this report the owner was called to account if unsanitary conditions were found existing.

Next to cisterns and water barrels, roof gutters were found to be the most general breeding-places for the stegomyia mosquitoes. Leaves and trash fall upon the roofs, are washed into the gutters, and these make little dams behind which water collects and remains after the rain has ceased. At other times the gutter sags and thus forms a collection of water. In the tropics you can always count upon roof gutters as being places for mosquito-breeding, and being inaccessible and difficult to inspect, such breeding-places are seldom disturbed.

During its larval stage the mosquito lives entirely in water, but has to come to the surface frequently for the purpose of getting air. This necessity is seized upon by man for the purpose of destroying the larvæ. If kerosene oil is poured upon the water, it spreads in a very thin film over the surface. Now when the larvæ rise to breathe, the oil gets into their breathing-tubes when they attempt to force them through the thin film of oil spread over the surface of the water. This suffocates and kills the insect and is very effective.

It is very surprising and impressive to see how rapidly such a system will free a city of mosquitoes, and how after a few months of such work you cease to be annoyed by them. In yellow-fever work this system of destroying mosquito larvæ is the essential; everything else is secondary to it. In the built-up portions of a city such as Havana, caring for the cisterns, water barrels and containers is the essential work, but as you approach the suburbs, pools and puddles become more frequent, and this character of mosquito breeding-places becomes more important than containers. Wherever possible these breeding-places should be drained, though oiling in this class of work has a very useful field. In the suburbs, in these pools and puddles, the anopheles, the malarial mosquito, becomes common and this disease has to be looked after. We had fifty men engaged in this work, under a different set of inspectors from those doing the stegomyia work. This was made necessary, as the men doing the anopheles work were occupied almost entirely in the suburbs of the city. The details I will describe in another place.

CHAPTER VI
THE RESULTS ACCOMPLISHED IN HAVANA

From the account already given of yellow fever it is evident that the parasite has to be introduced into a locality, either in the body of a human being sick of yellow fever, or in the body of a female stegomyia mosquito which has become infected by the parasite. It is evident that if the health authorities can keep out these two sources of infection, yellow fever can never occur in that locality.

With this object in view we established a modern quarantine at Havana. Any ship coming in with yellow fever aboard was placed in quarantine. The vessel itself was fumigated so as to kill all the mosquitoes. This rendered the ship safe. All the non-immune crew were taken off, carried to quarantine station, where they were cared for during a period of six days. If no sickness developed during this period, it was concluded that the infected mosquitoes aboard the ship had not bitten these non-immunes up to the time of their departure. They were therefore released and allowed to return. The immunes were not considered liable to yellow fever, even if they had been bitten by the infected mosquitoes.

One attack of yellow fever gives such great protection that, in practice, a man who can prove that he has once had the disease is looked upon as entirely safe. But of course he has to prove this to the satisfaction of the quarantine physician. It is considered so certain that everyone exposed to yellow fever will have the disease that proof that a man has lived in an endemic center for ten years is accepted as proof of his immunity. No quarantine is, however, absolute in any disease, in any locality, or carried out by any authority. Some people now and then will pass the quarantine who are either so slightly sick that the disease is not recognized, or who developed the disease after they had been released from quarantine. But a quarantine greatly lessens the number of times and the frequency with which infection is introduced into a locality.

For some reason yellow fever, in the minds of people generally, is covered with a cloak of mystery. In communities where it prevails there are hundreds of remedies and courses of treatment that are vaunted as being infallible cures, and the more ignorant and uneducated the possessors of these specifics, the more readily they seem to be accepted by the people generally. But yellow fever, like every other acute disease, has its own natural history, and man at present knows no remedy that can shorten or change its course. Many a time I have found myself completely routed in cases of yellow fever by the old negro mammy, who would insist that if the patient would take orange-leaf tea and adopt certain other procedures which she advocated, the patient would certainly get well. Now, on the average with severe yellow fever, seventy-five per cent. will recover and twenty-five per cent. will die. The negro mammy did not know this, but was firmly convinced that it was the orange-leaf tea which caused the recovery in the cases of those who recovered, and some departure from her directions that caused death in the case of those who died. She believed that if her routine had been carried out in the fatal cases, they would have recovered. I must confess, however, that in my experience the measures generally advocated by the negro mammy did little or no harm, and in looking back over a yellow-fever experience of thirty years, I cannot by any means make so strong a statement with regard to my professional brethren.

One of the most general superstitions with regard to yellow fever was that all air must be kept from the patient. With this in view, the room in which the patient was treated was kept closed and entirely dark. No water for washing the face and hands, no change of body or bed clothing was allowed during the course of the disease. The conditions, therefore, as to filth when a patient had been ill five or six days can be better imagined than described.

I was once called into consultation by a medical friend of very high standing in one of the best and most aristocratic Havanese families. The patient was a young American teacher who had been brought to Havana a few months before in connection with the education of a large family of children. She had been sick with yellow fever some five or six days when I saw her, and I recognized without much examination that she was fatally ill and had but a few hours to live. Her Cuban friends were devoted to her, and were willing to do anything for her comfort and recovery that their wealth could command. As is generally the case in yellow fever, her mental faculties were perfectly clear, and her physical strength good, although she died within six hours after I saw her. She was delighted to see me, and begged me earnestly to induce her friends to let her bathe her face and hands and have clean clothing; for neither of these luxuries had been granted her since she was taken sick. I urged my medical friend who had called me into the case to allow the poor girl to have these things, and I knew that he agreed with me that they could do no possible harm. He said that he would try, but that probably the only result would be that he would lose the confidence of the family and do the poor girl no good. We both urged this upon the family, but so strong was their belief that such a measure would deprive their friend of such little chance of recovery as was left that they would not consent.

In times of stress and danger such as come about as the result of an epidemic of yellow fever, many tragic and cruel phases of human nature are brought out, as well as many brave and unselfish ones. Some tragedies stand out prominently in my recollection.

When yellow fever was at its height in Havana, our chief commissary, an officer of the regular Army, was taken sick and his disease was soon recognized as being yellow fever. His wife had left Havana a few weeks before to make a short visit to her home in Cincinnati. I had promised that if my friend should get yellow fever, I would cable his wife. I did so, and the wife received the cable while at a dinner-party. She started for Havana at once and reached Las Animas Hospital a day or two before the Major, her husband, died. The tie between husband and wife was unusually strong, and as she was assured that hope was departing, her grief was very great. This was before we knew that the mosquito alone could convey the disease, and when we had some general idea that it was infectious, and in some way contracted by contact with fomites, and with those who were sick of the disease.

The wife as she saw death approaching determined, if possible, herself to contract the dread disease. I heard her appeal to her husband in most moving terms not to die and leave her alone. She was with her husband at the moment of his death, and held him in her arms at the time. One who is familiar with a deathbed scene from yellow fever can appreciate what this means. It is a very gruesome death, and the young wife was covered with “vomito negro.”

I felt myself more or less responsible, and thought that she was going into the jaws of death by this kind of exposure. I therefore called for the assistance of one of the nurses, and used some force in getting her into the next room. She at first reproached me, but as soon as we got her into the adjoining room she seemed at once to regain her mental balance, spoke rationally to Mrs. Gorgas, and asked me to arrange the details so that she could take her husband’s body with her when she sailed on the next vessel for the United States.

Mrs. Gorgas and I walked with her to her room and gave certain directions with regard to her care and comfort for the night. She asked me for a sleeping dose which she might take in case she was unable to sleep. I recollect that I put this up in such quantity that she could not hurt herself even if she took it all. The rooms were separated by very thin wooden partitions, and she asked about the location of persons in the adjoining rooms.

About two A. M. Mrs. Gorgas and I went to our quarters. We had been home just a short time when I was aroused by a hurried step and a knock at the door. I found it was a messenger summoning me to the hospital, with the information that the lady had killed herself.

When the door of her room was forced, we entered and found our friend apparently in a peaceful, quiet sleep. One arm had dropped naturally to the side, and the right arm was lying across the chest, the hand still holding the pistol with which she had killed herself. The appearance was exactly that of a piece of marble. She had shot herself behind the ear, and the hemorrhage had been so sharp that the body was entirely blanched. From where we stood the hemorrhage did not show. She had concealed a pistol in her trunk which she had procured in the United States at the time she started for Havana. She had placed fresh clothing on a chair by the bedside, apparently with the intention of being robed in it after death.

In looking back I could see various things in her actions and conversation that indicated the intention of taking her life. At other times she had entirely forgotten this, and was preparing for her sad future in this life. She had apparently been dazed by her grief and was temporarily unbalanced, unable for any length of time to follow in her mind any definite plan of action.

The Major having been our chief commissary and a man with whom we were in daily contact, this tragedy profoundly affected the military community. The next day we took husband and wife out to the little military cemetery at Camp Columbia where the American troops were cantoned, some five miles from Havana, and laid them to rest in the presence of a large concourse, military and civil.

While there, a member of the Commanding General’s staff, Captain Page, had a chill, returned home sick, developed a severe case of yellow fever and died within a week. This was looked upon by all the community as evidence that the disease had been contracted by contagion from the Captain’s having attended the funeral.

DEATHS FROM YELLOW FEVER IN THE CITY OF HAVANA

From the table on page [71] it will be seen that for ten years preceding our occupation of Havana there had been an average of more than five hundred deaths per year from this disease in the city; that in 1900, two years after we had taken possession of the city there were 310 deaths from yellow fever. A further search of the mortality statistics shows that yellow fever had existed in Havana continuously from the year 1762. This was the year during which Havana was besieged and captured by the English forces. The troops were largely made up of colonials from the North American colonies, and they suffered severely from yellow fever. For two hundred years before this time Havana had been subject to epidemics of yellow fever, but from 1762 up to the year 1901, there was probably not a single day when Havana did not have a case of this disease within its bounds.

In February, 1901, the measures above described were begun. Under these measures yellow fever rapidly disappeared, and in September of that year, the last case of yellow fever occurred. With one exception there has been no case of this disease in Havana since that date.

The work directed against mosquitoes had an equally good effect upon malaria. While the work done with the view of getting rid of the stegomyia was effective to a certain extent against the anopheles, the principal anti-anopheles work was executed in the suburbs of the city. It is a general rule that malaria does not occur in the heart of a city, but generally in its outlying districts. The reasons for this will become evident when I describe anti-malarial work in one of our future chapters.

Deaths from Malaria in the City of Havana

It will be seen from this table that before the year 1901 Havana had yearly from 300 to 500 deaths from malaria, rising as high in 1898 as 1,900 deaths. Since 1901 there has been a steady decrease in the malarial death rate until the last year of the table, 1912, when there were only four deaths. Four deaths from malaria in a city of the size of Havana, about 300,000 population, means the extinction of malaria in that city. For the island of Cuba is in the tropics, and there are many malarious localities through the country districts. Havana is the metropolis of Cuba, and has in its environs the largest and best equipped hospitals of the country, as well as the most distinguished surgeons and physicians. The sick, therefore, are brought from the country in considerable numbers, and a great many cases of malaria are brought in among these outside sick. The tables quoted above include all persons who died within the limits of the city of Havana, whether they came from the outside, or were residents of the city; whether they died in the large hospitals of the city, or in private houses.

Four deaths in one year from malaria can very safely be put down as coming from the outside, and it can with equal safety be said that by 1912, malaria had become as completely extinguished in Havana, as had yellow fever in 1902.

The extinction of malaria, however, did not attract anything like the attention that the extinction of yellow fever had aroused. The work of Dr. Ronald Ross and his co-workers with the anopheles mosquito, and of Reed and his associates with the stegomyia, undoubtedly gave the knowledge whereby the practical extinction of malaria and yellow fever was accomplished at Havana, but the accomplishment of this work with regard to yellow fever was the event which attracted the greatest attention. It seems almost providential that we had all the machinery at hand whereby the discoveries of the Reed Board could be immediately tested and demonstrated. Here was a large city of 250,000 inhabitants in which yellow fever had been endemic for one hundred and fifty years. The American Army had been in control of the city for two years, and the Health Department was thoroughly organized and equipped and under the charge of a medical officer of the regular Army. Dr. Reed himself was strongly impressed with the advantage it had been to him to have his discoveries given so thorough and conspicuous a test, and wrote me to that effect many times.

There has been a great deal of discussion as to who deserves the credit for this great discovery. Undoubtedly Reed and his Board brought all the threads together and actually made the great discovery, but Finlay, Sternberg, Carter and others, started the spinning of many of these threads. Like all great discoveries everywhere it was gradually led up to by many workers.

Nothing is more true than the following quotation from one of Huber’s papers:

And let me premise here, that in science at least, great names are landmarks; and the owners of these names have traversed and gleaned in fields where many a devoted laborer had delved and sown, and pathetically sweated blood in his altruistic zeal. In science at least no man works in vain. Full many an one, worthy of an elegy, has given his whole life to establishing a fact, or indeed only an item to a fact; his work unrealized, ridicule and even persecution ofttimes his only compensation, throughout perhaps in the meanest destitution, yet his life and his work have been absolutely essential to the building of a mighty fabric. Martyrs have been many among such—dying from the diseases from which they sought to defend others; knowing, too, full well, what their own fate would be. Nor does it in any wise detract from the gratitude due the great man that he has profited by the labors of others, adding what he can of his own, scrutinizing every detail, every datum, permeating and illuminating with his own genius, cementing the mass with his own deductions.

And from Flexner:

Remarkable achievements are never unique occurrences in nature. Even the greatest men rest on the shoulders of a multitude of smaller ones who have preceded them; and epochal discoveries emerge out of a period of intellectual restlessness that affects many minds.

CHAPTER VII
CORRESPONDENCE WITH DR. REED

As illustrating the way in which we looked at conditions at Havana at the time that our mosquito work was first begun, I will quote correspondence which took place between Dr. Reed and myself at this time.

(1)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, May 16, 1901.

My dear Gorgas:

Briefly speaking, how is the yellow-fever situation in Havana? I got your report for April and noted, with much pleasure and satisfaction, your enthusiasm in tackling C. fasciatus and her numerous cousins. Later, I think on May 4th, I read of “a serious outbreak” in your town, to the extent of two cases. Since then I have heard nothing concerning the progress of your epidemic. How many cases have you at the present writing, and what are your prospects of prognostications for the future? I ask for this information particularly because Dr. Durham, of the English Commission, in a letter recently received, has proposed to join us in Cuba for the purpose of trying to reconcile his work, or rather the results of his work, at Para, Brazil, with our observations at Quemados, and as he will reach here during the last week in May, it is barely within the bounds of possibility that you may again see us back in our old haunts by July 1st. Everything will depend upon Dr. Sternberg’s decision.... As much as I should like to see you and other friends, I would prefer to spend the summer in the United States. I hear that my friend, Kean, has been promoted to be the head of Charities and Correction for the Island. Who, then, is Post Surgeon at Columbia Barracks? How does Dr. Guiteras succeed at his propagating station? I trust that your own and Mrs. Gorgas’ health is very good. Please remember me very kindly to the latter and to Col. Havard and Glennan.

Sincerely yours,
Walter Reed.

(2)

Havana, Cuba, May 22, 1901.

My dear Reed:

Yours of the 16th received. I wrote you a day or two ago, but I have forgotten whether or not I answered your question.

The fever situation is all that could be desired, I think. The last death from yellow fever occurred on March 13th. Since that time we have had a case April 21st; another on April 22d. We had no more cases then till May 6th, when we had one; and on May 7th, three more. Since that time, two weeks, we have had no more; and as the conditions, as far as non-immunes are concerned, seem more favorable for the spread of yellow fever, I am in high fettle.

I am inclined to attribute our freedom to the way in which we killed the mosquitoes. We have fifty men at this work, oiling and draining small collections of water in every house and putting oil in all the sinks and closets so that it will run down into the cesspools. During the winter and cool periods of the year, up to this time say, the cesspools are the great places for breeding mosquitoes. All the cesspools, so far, have larvæ in them; when water barrels and cisterns in same yard have none. I am inclined to think that Dr. Guiteras, and other mosquito breeders, would get much more vigorous larvæ if they would use blood or some richer food than mere bread. We have been trying them side by side and find that sewer water develops much more hardy and large larvæ than rain water with bread alone in it.

I have had all the little streams and ditches in the suburbs cleaned and oiled; and we have killed a great number of larvæ.

You can go to any sewer mouth now and see the dead larvæ running out in considerable numbers, coming principally, I think, from the fosomauros, where they have been killed by the oil which would no doubt remain upon them for several hours.

But we have evidently had some tough old infected fellows, who have hibernated through the winter. For instance, on the two cases that occurred on the 21st and 22d of April (in different parts of the city, however), the mosquitoes were killed as thoroughly as we knew how. Every room in the house was closed; and a pound of pyrethrum powder burned to 1,000 cubic feet, and oil used everywhere, sewers and everywhere else. Not only was this done in the infected house, but in the fifteen or twenty contiguous houses. On each case we used 50 pounds of pyrethrum powder and something like 40 gallons of oil. I think the results show that we probably got hold of the infected mosquito or mosquitoes. We did the same thing on May 6th and 7th; and it now looks as though we had gotten hold of the infected mosquito there.

The prospect of getting infected mosquitoes now is poor. So far we know of none in Las Animas; all the cases this year having been exceedingly mild. It takes a Board with decided “amarylic” to diagnose them.

Would like very much to see you, Durham and Carroll down this summer, that is if you did not object to coming.

Dr. Gaylor, of the New York Pathological Laboratory, wants to take a whack at yellow fever, after his success at cancer. He asked me to let him know when I could get him some more autopsies of yellow fever, and he would come down at once.

We have things nicely fixed at Las Animas now; and I think we would do good work if we only had yellow fever; but of course we can do nothing if we don’t have.

Mrs. Gorgas has just returned from the “States” and joins me in kindest regards. I got weak in the knees and was afraid to keep our small girl down here, even though we had no infected mosquitoes.

Very truly yours,
W. C. Gorgas.

(3)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, May 23, 1901.

My dear Gorgas:

I had only just penned you a short note, inquiring into the yellow-fever situation, when here comes your most welcome and interesting letter of May 15th. I was so much interested in Guiteras’ results. One positive case in nine inoculations is better than we had at first. We only succeeded with our tenth individual. Of course, you were biting often with non-contaminated mosquitoes, as your fever cases were doubtful. Cases 3 and 6 should have failed. I expect better results from your May-infected mosquitoes. I see that Finlay and Guiteras continue to harp on the harmlessness of a single mosquito’s bite, drawing the conclusion that ordinarily y. f. is due to multiple bites. After some poor devil dies, they may change their minds. Carroll’s severe illness was due to a single insect and poor Lazear died from a single bite. Why are not malarial fevers generally double or multiple infections? We know that the opposite—single infections, as shown by one group of parasites—is the rule.... What’s the need for us to return, if you have no y. f.? Havana should get a more accommodating Chief Sanitary Officer! Hurry up your new infections.

Again thanking you for your letter and the copy of G.’s report, and with best regards to your wife, believe me,

Sincerely yours,
W. Reed.

(4)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, June 5, 1901.

My dear Gorgas:

Your very kind letters of May 22d and 23d have both been received. Please say to Dr. Finlay that I will send a copy of our last paper just as soon as we can get it from “American Medicine.” It hasn’t been published yet. I hope to have it soon. You shall certainly have a Reprint. What you tell me about the y.-f. situation is certainly very encouraging, but were not the results just as encouraging in 1899, at the same season? I will admit that you must have more non-immunes in Havana now than in 1899. Of course, you understand, my dear Doctor, that the control of yellow fever during this epidemic season, is to me the all-absorbing and important question, and it is on this very account that I am afraid that you and I might be led, in our enthusiasm, to think that more should be attributed to the sanitary measures now being carried out, than to the season, or some other conditions of which we might be ignorant. It is simply a delight to read that you are “in high fettle,” and I consider the city fortunate in having a Health Officer who believes that he can master the problem. I am astonished at the strength of your mosquito-destroying sanitary squad. What you say about the cesspools as breeding-places is intensely interesting. We got our first good supply of larvæ from an old can containing some feces at Columbia Barracks, and since then we have added a little fecal material to our breeding jars and have found that larvæ thus fed grew much more vigorously than those in ordinary water. Your experiments agree fully with ours. You are certainly doing effective work toward their destruction. I was astonished at the amount of pyrethrum that you are burning to the 1,000 cubic feet. Is such a large amount necessary, do you think? Won’t you soon exhaust the supply? At Mount Vernon B’ks, where culex was very abundant, I used to find that about 2 or 3 ounces would intoxicate every mosquito in a room of some 3,500 cubic feet, so that I could sweep them up and burn them before they “sobered up.” Certainly your plan of destroying insects in the surrounding houses is worthy of all commendation. However, be sure that your sanitary measures do not prove obnoxious to the Cuban doctors and laymen, or otherwise they will certainly conceal their milder cases. While the destruction of the mosquitoes is very desirable, I consider the thorough protection of the patient against their bites as of even greater importance. I cannot believe that in so largo a city ... that you can possibly accomplish this. The undertaking, to me, seems well-nigh impossible. They will conceal their cases, do what you may; and these cases will be the foci for other cases. I can see no other alternative for this summer, at least. Still, you will undoubtedly be able to control the spread of the disease better than ever.... Pardon this long letter. Good luck attend your well-conceived regulations. Health and happiness attend you and yours.

Sincerely, your friend,
Reed.

Dr. Reed here considers a squad of fifty men doing sanitary work in a city of two hundred thousand inhabitants at large. Four years afterwards, in the city of Panama, a place of twenty thousand inhabitants, we had six hundred men doing the same work. Major Reed is inclined to think fifty pounds of pyrethrum to a case a large amount. In 1905 in Panama we used two hundred and forty thousand pounds during the year. I call attention to this as showing how little any of us appreciated the magnitude of the job when we first started in.

(5)

Havana, Cuba, June 13, 1901.

My dear Reed:

Yours of June 5th received. I inclose you a copy of Dr. Guiteras’ report for May.

We see still no success from our inoculations in twenty-two cases, but the great “but” comes in. I am not sure that any of the cases bitten were yellow fever. One of the last, from Tampico, I thought a pretty well marked case, though not dangerously ill, but his mosquitoes, on the 20th day, did not infect. I am disappointed beyond measure. I had hoped by this time to have Las Animas full to overflowing with inoculated cases, and be turning out immunes at the rate of some two hundred a month. But may be it is well as it is; in our enthusiasm we might have infected the city.

No case of yellow fever since May 7th, and still none on hand. The Board diagnosed one early in the month, but it turned out a well-marked case of typhoid fever. Of course I agree with you that nothing very definite can be deduced from our results this early in the season, though personally I am very much impressed by them. Our condition now is very much better than it was even in ’99, with regard to yellow fever, and of course our liability to it is very much better. ’98 and ’99, with regard to yellow fever, should be left out, as in these years there were no non-immunes in Havana, and they would not have had yellow fever no matter what the condition of infection would have been. I except of course, the latter part of ’99.

From the 1st of March to the 16th of June in ’99 (and mind you this has been far and away the best record Havana ever made), we had four deaths from yellow fever. In the same period this year, we have had one, which occurred March 16th. The deaths in ’99 occurred scattered over this period. It seems to me that the present condition of affairs indicates that we have been doing something that has had a great effect upon infection; and of course the only thing we have done this year that we did not do last year is the destruction of the mosquito. We commenced this work about the middle of February, just about the time that yellow fever practically disappears.

On the 12th of June, 1899, we had had for the month two cases of yellow fever, and in 1900, six. If you consider the amount of work there was to be done, to put oil in all the cesspools, all the water barrels and all the cisterns, once a month, and then keep the streams and pools in the suburbs drained, you will understand that seventy-five men is not at all a large force. I think I could use to advantage more. As you say, we could use less pyrethrum. We arrived at the rate of a pound per 1,000 cubic feet by experiments at Las Animas. We found that in this ratio we could kill mosquitoes in one and a half hours. It would probably be just as well to intoxicate them and sweep them up, and I shall probably cut down the quantity in a short time. We have to sweep them up anyway. But feeling that it may be possible that we have no infected mosquitoes in Havana I want to do everything I can think of, when a case occurs, to increase the chances of killing the infected mosquito in the neighborhood of where the patient got his infection.

We are using now from one hundred to two hundred pounds to the patient, killing the mosquitoes everywhere within half a dozen houses of the patient’s home. There is less objection raised to this than to the ordinary disinfection. It damages nothing, only keeps them out of their room for an hour or two, and kills the mosquitoes. I think there is much less opposition to us on this account than there was last year.

I feel confident that there is very little concealment of cases, and I do not feel much anxiety on this score. We cannot have many light cases without having a death now and then, and deaths would almost certainly be reported.

But what gives me the greatest confidence is that our non-immunes are made up entirely of Spaniards and Americans. The Americans promptly report themselves where there is anything suspicious, for the sake of the better care that they get at Las Animas. The Spaniards are all matriculated at one of the three “quintas,” and go there as soon as they are sick from any cause. These “quintas” are all very anxious to try and catch up to the record of Las Animas, and report every case that they think, by any possibility, will pass the Board. And then, too, I can control the “quintas” by frequent inspections. So it seems to me that there is very little probability of cases being concealed to any extent. Still, we can speak more definitely on this subject about the 1st of December than we can now.

All well. With kindest regards, I remain,

Very sincerely yours,
W. C. Gorgas,
To Maj. Walter Reed, Maj. & Surg., U. S. A.
Washington, D. C. Chief Sanitary Officer.

(6)

Army Med. Museum, June 27, 1901.

My dear Gorgas:

I thank you so much for your last kind and most interesting letter of June 13th. Really, my dear Dr., in spite of a few disagreeable things and people, when I think of the absence of yellow fever from Havana for a period of fifty days, I begin to feel like rejoicing that I ever was born! You are doing a splendid work for your corps and profession in Havana.

Sincerely, your friend,
Reed.

(7)

Army Med. Museum, Washington, July 29.

My dear Gorgas:

I was on the eve of writing to you, when your kind favor of the 20th inst. reached me. The news from Havana is simply delightful. I am willing to confess that my fears that physicians would fail to report cases of yellow fever to your office, and thus maintain foci of infection, were groundless. It shows that your acquaintance with the local conditions were much better than mine. That you have succeeded in throttling the epidemic appears to be beyond question, and is to your everlasting credit as an energetic Health Officer, who saw his opportunity and grasped it. A man of less discretion, enthusiasm and energy would have made a fiasco of it. Whereas, you, my dear Gorgas, availing yourself of the results of the work at Camp Lazear, have rid that pest hole, Havana, of her yellow plague! All honor to you my dear boy! Thank God that the Medical Department of the U. S. Army, which got such “a black eye” during the Spanish-American war, has during the past year accomplished work that will always remain to its eternal credit! I had seen in the papers report of the cases at Santiago de las Vegas. I am delighted that you have taken charge of the suppression of this outbreak. Of course, you will soon stamp it out, if you can enforce your regulations. I shall look forward with the greatest interest to your work there. Please keep me posted. I did not get your June Report, which I should like to have very much. Apropos of the outbreak at Santiago de las Vegas, I have concluded to have Carroll go to Havana, for the purpose, if he can get hold of any cases of yellow fever, of making a few observations on human beings, which will be a valuable guide to us at the present stage of our search for the parasite. I sincerely hope that he can succeed in getting hold of a few recently arrived immigrants for this purpose. I especially ask your kind assistance in this matter. I see that Gen. Wood has left Havana so that I am afraid that Carroll cannot get any money with which to pay the subjects of experimentation. Have you any funds with which they could be paid $1.00 per day? I think that you said that subjects could be obtained at that price. Carroll would like to do his work at Las Animas Hospital. Can that be arranged? He must start on his return by Sept. 20th, if possible. So that he has but little time in which to accomplish the task before. Still if he can draw blood from a few undoubted cases and can get a few subjects, it won’t take him long to decide the point. I wanted to come very much, but I have work here which I feel that I should not neglect. Else I should have certainly come down. I have been intending to ask you whether, in dealing with y. f. in Havana, this year, you have confined your work to simply protecting the sick against bites and destruction of mosquitoes; and have omitted all disinfection of bedding and clothing. I sincerely hope that this is true. I shall probably present, with Carroll, a paper to the next meeting of the American Public Health Association on the management and prevention of yellow fever, and I would so like to be able to say that the great work in Havana was accomplished without the disinfection of any bedding or clothing. Carroll leaves New York, with Pvt. Springer, on Ward Line leaving on Wednesday, August 6th. Pardon this lengthy letter. Please present my kindest regards to Mrs. Gorgas. Keep me informed of your progress at S. de las Vegas.

Sincerely yours,
Reed.

The parasite has not yet been discovered. Dr. Carroll proved by the experiments which Dr. Reed here refers to that the parasite of yellow fever is sub-microscopic.

(8)

Havana, Cuba, August 26, 1901.

My dear Reed:

Yours of July 29th received. You will see by the last report that our conditions continue good. So far this month we have had only two cases belonging to Havana, one of these a Cuban child twelve years old who had never been out of Havana. Personally, I have not seen a case since March, belonging to Havana, with which I was perfectly satisfied as being yellow fever, but I am more confirmed in my suspicions since we have had the Santiago de las Vegas cases.

You recollect we bit some thirty-four subjects at the time when I last wrote you without being able to transmit the disease in a single instance. These mosquitoes we tried to infect on some dozen of these supposed Havana cases.

We all agreed that the Santiago de las Vegas cases were yellow fever. While they were not severe, they were well-marked cases of yellow fever. We bit one man with eleven mosquitoes. He was a well-marked case, but not dangerously ill at any time. These eleven mosquitoes have since bitten seven subjects, six of whom have gone down with yellow fever. Three have recovered and three died. Carroll will no doubt give you details in these cases, and Guiteras will publish the matter in detail.

I am very much disappointed. I had hope that through the mosquito we had a means of giving mild cases which would protect, but these cases show that the severest form of yellow fever can be transmitted by one or two mosquito bites.

I suppose I ought to be thankful for the immense good that the discovery so far has done, and for the great success that our work this year has had, but the death of these patients, just now, makes all success taste of gall and wormwood, and casts a gloom over the Sanitary Department.

From a practical standpoint though I am inclined to think that the yellow-fever question is settled. The discovery that it is the mosquito alone that conveys the disease will enable us to manage it.

I cannot but think that the freedom of Havana from yellow fever on the 24th of August, a thing never before known, must be due to the fact that we got the infected mosquito nearly every time. The disease has been introduced freely from the outside, and yet has not spread among our thirty thousand non-immunes. I believe that our system gets them nearly every time. I think we will soon have Santiago de las Vegas under control. We are inspecting and keeping track of all the non-immune travelers coming to Havana. They are seen by one of our doctors every three days of their stay in Havana, up to six. We have gotten hold of several in this way, and the town is being regularly gone over with the same system that we have in Havana.

We had a case on the 20th from Las Vegas, but it was from a part of that town that had not been disinfected. I feel confident that we will have no more cases from Las Vegas after September 1st. This will be a very nice demonstration of what can be done by our system of mosquito killing.

Heretofore we have disinfected exactly as last year, plus using the pyrethrum powder and oil in the infected house and in all the neighboring houses. Formaline was used in the infected room and the clothing was sent to Las Animas Hospital, and the patient quarantined. I did it because it could not decrease the effectiveness of disinfection, and would relieve me from criticism in case we were not able to control yellow fever, and had as much as we had last year.

I must confess that our results this year are entirely unexpected to me, and if I had any idea how they were coming out I might have discontinued the disinfection of clothing long ago. But in order that the cases may be reported as generally as possible, I am doing everything that I think I safely can to make the routine as little burdensome to the people, as possible. In accordance with this, I have this month issued an order that in yellow-fever cases the only disinfection was to be with pyrethrum; that the clothing was not to be taken to Las Animas, and that after the fifth day the patients were not to be quarantined or screened.

I have been designated by the Military Governor to represent the Department at the Public Health Association next month at Buffalo, and also the Board of Health at the meeting at Niagara which is scheduled to occur on the 13th. I hope to see you there if I go. If things are as quiet as they are now, I will probably go; but if I have any yellow fever on hand I would rather send somebody else.

Yes, I agree with you. I think this yellow fever work will reflect great credit upon our corps. Certainly the work of proving the mosquito to be the transmitter of yellow fever is as important a piece of work as has been done since Jenner’s time, and as far as the United States is concerned, probably of more importance; and as yours was the guiding hand in the whole matter, I hope that some suitable reward will come to you, more substantial than the general professional recognition which you are now getting from all quarters. I am very happy to shine in the more humble rôle of being the first to put your discovery to extensive, practical application.

Mrs. Gorgas joins me in kindest regards.

Very sincerely yours,
W. C. Gorgas,
Major & Surgeon, U. S. A.,
Chief Sanitary Officer.

(9)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, Sept. 2, 1901.

My dear Gorgas:

Upon returning to town, from a two weeks’ rest in the mountains, I find your very interesting letter of Aug. 26th. Of course, Carroll had already written to me about the unfortunate termination of some of Guiteras’ cases. I was very, very sorry to hear of Guiteras’ bad luck and can appreciate fully his mental distress over this loss of life. Perhaps, after all, the sacrifice of a few will lead to the more effectual protection of the many. I think that we had best look at the matter in this light. That eleven mosquitoes could and did infect six persons, causing the death of three, is indeed, very strong confirmatory evidence of our observations of last fall and winter. I have been particularly anxious to learn of your results at Santiago de las Vegas, hoping to incorporate them in a paper on the prevention of yellow fever, which I hope to read at Buffalo; but since the good news comes that you will be there “in persona vera,” you can give the figures better than anyone else. I will, however, show by chart, the occurrence of yellow fever in Havana during the present year, and would be so glad if you would give me your cases and deaths for August. To Aug. 26th, you report only two cases. Were there any others? I have the cases and deaths for the other months. Is not the record a glorious one? But it would not have been obtained by a less energetic and enthusiastic Health Officer. You, therefore, my dear Gorgas, deserve all manner of praise for your thorough work. I hope that Carroll is meeting with success. Please let me hear from you by return mail, if possible, about your August cases and deaths. A line will do. With kindest regards to Mrs. Gorgas,

Sincerely, your friend,
Reed.

(10)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, October 3rd.

My dear Gorgas:

I have been hoping to see you and Mrs. Gorgas in Washington and wondered what you found at Buffalo to keep you so long; but a letter from Carroll just received, mentions your return to Havana. So you have, indeed, given us the “glad go-bye!” Well, as Columbia has just won from Shamrock, I’ll have to forgive you this time! But you mustn’t do so any more, or there will be “trouble on the old man’s mind.”

I trust that you found the yellow-fever situation satisfactory. I wish that I could have known the No. of cases and deaths for September, so that I could have included them in our paper, but it is too late now. Don’t forget to keep me on your exchange list. I had a letter from your brother in answer to one I wrote you for which please give him my best thanks. You were saying, if I remember, that you would like to have your former assistants, Lyster and Shockley, back again. If you haven’t them, and still want somebody, I only mention the fact that Asst. Surgeon Devereux, who has been on duty with Borden at the Genl. Hospital here, leaves in a day or two for Havana, to report for duty, and might suit you very well as an assistant.... Borden says that he has made a very good assistant. You might have your eye open for him. Give my kindest regards to Mrs. Gorgas. Good-bye.

Sincerely, your friend,
Reed.

(11)

Havana, Cuba, Oct. 8, 1901.

My dear Reed:

I was sorry that I did not see you before leaving Buffalo, and have an opportunity of talking with you over your superb paper, and arguments with Wadsin. Nothing could have been clearer, it seems to me. I congratulate you upon being the First Vice-President; I think you ought to have been President but that matter had been arranged beforehand as going to the retiring Treasurer, who had held that office so long. Other names as First Vice-President had been proposed to the Committee, but when your name was mentioned, they all voluntarily withdrew, and you were nominated without a single dissenting voice.

You will see from the report how we are coming along. The record is just as good; two deaths for September. We have had a little focus about the “Mercado del Vapor,” but I think we have squashed it. Our last case occurred Sept. 26th. Ten days without a case, this time of the year, is pretty good. But our general death rate took a most remarkable drop. We had only 339 deaths in September, a rate of 15.64 per thousand.

You had better move down to Havana with your family. I am getting so that I am afraid to go back to the United States and run all the risks of infection and bad hygiene that you are constantly subjected to in cities such as Washington, New York, etc.

I looked into it carefully, and am positive that there is no error in the figures. I don’t believe it is possible for a person to be buried in Havana without my knowledge, and I know that these figures are correct.

Carroll seems to be hard at work; looks very mysterious, and can’t get him to tell anything. He had better hurry up; yellow fever in Havana will soon be a thing of the past.

I left Mrs. Gorgas and Aileen in New York, but expect them to leave for Havana, Wednesday, the 9th.

With kindest regards, I remain,

Yours very sincerely,
W. C. Gorgas,
Major & Surgeon, U. S. A.,
Chief Sanitary Officer.

Major Walter C. Reed,
Office of the Surgeon General,
Washington, D. C.

This case which I report on September 26, 1901, was really the last which occurred in Havana. Of course we did not know it at the time, but this case marked the first conquest of yellow fever in an endemic center; the first application of the mosquito theory to practical sanitary work in any disease.

(12)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, Oct. 17, 1901.

My dear Gorgas:

I have yours of the 8th inst., and appreciate very much your kind words about my paper and my selection for First Vice-President of the Association. The latter was a very great surprise, as I didn’t dream that I would be considered as a candidate for any office.

I am indeed delighted to hear that you only had two deaths in September. What could be more satisfactory? Certainly five deaths in seven months is a good record for the city of Havana, in this year of our Lord 1901! I hope that you no longer destroy fomites but are careful to protect your cases until fever subsides or death ensues. Good luck to you and your work! I really don’t blame you for being a little nervous about your health when you come to the United States, for you are certainly making Havana one of the healthiest cities in the world. I think that I will take your advice, come down and build me a house; that is, after I retire! Remember me very kindly to Mrs. Gorgas and your daughter.... I will be glad to get your monthly report for September.

With best wishes,

Sincerely yours,
Walter Reed.

(13)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, Dec. 21, 1901.

My dear Gorgas:

Many thanks for your October report. The November report has not been received yet, but hope to get it later. I got your kind letter of Dec. 6th. Certainly the results for October and November could hardly be beaten. I think that we should thank Heaven and be satisfied. Another experimental case of yellow fever? Look here, Mr. Sanitary Officer, if you don’t stop applying stegomyia to willing Castilians, there will be trouble yet! Carroll fairly grinned all over when I read it to him! He wishes to be very kindly remembered to you. I am glad that Dr. Finlay still finds his Tetragenus. Please remember me to him. What a splendid paper that was of Guiteras in American Medicine! I was delighted with it. Make my best regards to him, also, please. The weather here is so very cold that I long for the balminess of the Cuban atmosphere. Why men and women will persist in living in cold climates is something that I can’t possibly understand. Stay where you are. Don’t permit even the evacuation of the Island to bring you away. We need you as a defence against yellow Jack! Well, the hour is five p. m. and all have long since left the office. I must hurry home in an open street-car and thereby chill my very marrow. My best regards to Mrs. Gorgas....

With all manner of greetings for a Merry Xmas and happy 1902, believe me,

Sincerely, your friend,
Reed.

(14)

War Department, Surgeon General’s Office,
Army Medical Museum and Library,
Washington, Jan. 14, 1902.

My dear Gorgas: