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THE
SEAMAN’S
Medical Instructor,

IN A COURSE OF

LECTURES

ON

ACCIDENTS AND DISEASES

INCIDENT TO SEAMEN,

IN THE VARIOUS CLIMATES

OF THE WORLD.

CALCULATED FOR

SHIPS THAT CARRY NO SURGEON.

The Whole delivered in a plain Language, and founded

on a long and successful Experience.

By N. D. FALCK, M. D.

LONDON:

PRINTED FOR EDWARD AND CHARLES DILLY.

M,DCC,LXXIV.

THE
PREFACE.

If we consider the many benefits that navigation contributes to commerce in general, and how much the prosperity of nations are indebted to its source, we must without hesitation declare seamen, a most respectable part of mankind; and if we reflect a moment, on the many hazards and perils they are exposed to on that precarious element, and the advantages we reap from their toil, the common feelings of human society, must awake and remind us, not only how much we are obliged as social members, even from a motive of self interest, to study their preservation, but as fellow creatures, how forcibly our duty calls us to give them every aid in our power, and to lighten the burthen of their many toils.

A ship at sea may be considered as a floating kingdom; and the subjects, however few in number, are not only liable to the same accidents as those on shore, but to many more, peculiar to that precarious and fluctuating element that surrounds them. For this reason there are many things requisite to be known by the mariners besides the art of conducting a ship from port to port.

Of all the various knowledges that distinguish the human species from the brute creation, what is of more value than that which tends to the preservation of life and health? I believe that every man who is actuated by motives of philanthropy will with me wish, that mankind in general would advert more to it in the principles of education, than what they at present do. Indeed it is astonishing that so valuable an acquisition, as to have some knowledge of the body we possess, and its preservation, should be so totally neglected, as to be entirely excluded from education; an acquisition that not only enlivens the mind, but in itself is so very essential to our existence; yet what is more to be wondered at, is, that a seaman who launches into the main ocean, is cut off from every assistance, in case of an accident or sickness, and rendered wholly unable to give the least aid to himself, or those who are entrusted to his care. Large ships I own are exempt from this observation: but are not the lives of men on board of small ships equally as valuable, and worth preserving, as those of greater burthen?

I am not the first who has had the welfare of seamen at heart; various writers, and men of abilities too, have presented the world with observations, that undoubtedly have proved beneficial to that class of men; but then these books were neither intended, nor fit to be put into the hands of such seamen, as actually stand most in need of those very observations they have made, and only intended for the perusal of men of physical talents; nevertheless they merit for their labour public thanks, as useful members of society. But if we take an impartial view of the number of seamen, I believe the greatest part are employed in small ships, that either carry no surgeon, or (I am sorry to say it) sometimes one they had better be without; especially in war time, when they stand most in need of a good one.

To benefit these men, and at the same time to make that benefit universal, is the plan I have aimed at; and I believe this is the first attempt of the kind; at least I know of none whose steps I have followed in this design.

Should I ask physical writers why they have neglected so valuable a part of society as seamen, in giving them their friendly instructions respecting their health, I doubt not, but the majority would reply, that the education of masters of ships and seamen in general, has not enabled them to understand a subject so much above their comprehension, or sphere. But if seamen have not the advantage of an extensive education, are they divested therefore of common sense and understanding? and is it not possible to deliver them instructions, dressed in so plain a language as to adapt it to their capacity?

Nevertheless, though men of abilities have not thought seamen worth their pen, others have; but such whose pursuit in life has been stimulated by motives of a different cast. Those have furnished seamen not only with directions to cure all diseases, but even given them medicines to do it with, into the bargain; or to speak more seriously, given them directions how to use such medicines as would yield the most profit to the apothecary, who with pretended wisdom equipt them out: and I am apt to think, that kind of quackery has stolen away the lives of many valuable seamen.

It is universally asserted that seamen are not fond of reading; this in a great measure is true, but far from being a general rule; and though blind prejudice has given them an aversion to every thing physical, yet I will venture to say so much in their behalf, that hitherto nothing has been offered to them that could alter their opinion in this respect, or open their eyes, in shewing them the beauties of that useful study, and in how small a compass its true principles might be contained.

Physic like religion is rendered intricate and abstruse, the more it abounds in errors and absurdities; but truth like the brilliant sun, drives away all the phantoms of perplext mysteries, and proves that both alike are simple and beautiful, founded on reason, and that its most useful part is comprehensive to common understanding. This pleads in favour of my attempt, and with every man of sense, must overpower prejudice.

That I might the better succeed in my intention, I have begun the whole at the first principles, namely the mechanism of the human body; for I cannot see how any man can pretend to know the nature of diseases, or presume to administer any thing with certainty, without he has some knowledge of the parts that suffer: this then is the subject of my first lecture; and to make it the more pleasing, and to entice the reader to pursue, I have stript it of every thing pedantic, or the unnecessary perplexing particulars, and confined myself to such things only, as gives a concise and true idea of the whole animal system; and if I may be allowed to judge from the opinion of some of my learned friends, I flatter myself, that my readers, physical or not, will give me their sanction, as well with respect to plainness of language, as conciseness of the subject, and the utility of such a short dissertation, founded on experience, and stript of prejudice and errors.

The second lecture contains equally as copious a subject as the first; contracted in a very small compass, and which I hope will give as much satisfaction as the forementioned.

Out of the whole Materia Medica, I have chosen but very few medicines, and these I have confined myself to throughout the whole book. Many surgeons at sea will not, I know, be contented with so small an assortment; and I remember the time that such an observation might have been applicable to myself; but as I have by long experience learned to shake off prejudices, and been taught by the help of philosophy to pry into the nature of things in general, I solemnly declare, that now, I would venture to go to any part of the globe, not only with that little assortment of medicines I have mentioned, but even with many less. The emetick tartar, sublimate mercury and the bark are powerful medicines; but they should be in very skillful hands, otherwise they are rank poisons, and therefore I have omitted them here; but strictly speaking, every good medicine is the same. I have two maxims in physic, which I strictly attend to; one is, that to my friends I give the least medicines; the other is, that the principal virtue of a medicine depends on its application.

The form of the medicine box, I have constructed so as it appears to me most convenient and handy; and every kind of medicine, I would advise to have labeled with their proper names, as well as with another mark that may take the eye at first sight; and the more to prevent mistake, one label should be fixt on the pot that contains the medicine, and the other on the box: for in medicines too much caution cannot be used.

One thing with respect to the medicines, I have omitted, and that is their quantity requisite for the box, and their prices: I intended to have taken notice of this, but found that that could not with exactness be ascertained, unless entering into another subject, and that would take off from the conciseness of my plan. As I have however many other things respecting the benefit of seamen to offer, peculiarly respecting distant climates, I shall take notice of this, where it may come in, more pertinently to the subject: till then, that must be left to the management of the apothecary who is applied to for fitting out the box. If he is a man of candour and judgment he cannot be much out of his calculation, when he knows the number of hands, and the voyage intended.

With respect to the other lectures, I have, as near as it was practicable, divided them into their different classes and sections; at the same time the whole is so linked together, that one lecture must support the other. And as I have throughout the whole course of the book differed more or less from the general mode of practice, I must hereby declare, that I have in this consulted my own experience more than any other authority, without fear of censure, or hope of applause, any farther than of truth, and my own conscience.

Though I have principally written with an intent to be understood by masters of ships who carry no surgeon; yet I am well persuaded that every practitioner, whether on sea or shore, will find many things to his improvement.

With respect to my receipts, they are simple and powerful; yet I do not enjoin so strict a conformity to them, by the practitioner, who has an extensive knowledge of the materia medica, and is prepossessed in favour of some particular medicines; but as he will discover my indications, it may serve greatly to compare that of mine with his own, and then he may judge for himself. I have touched very slightly on the requisite diet for patients on board a ship; though this is an essential article regarding health in general: But I found that subject also of so very extensive a kind, that it would swell the book; but as I have many valuable things to offer of the same nature, I must beg, that in the mean time, the reader will be satisfied with the universal observations in general; namely, that temperance is the principal object and that patients who are deprived of exercise ought to have the most easy digesting food. Copper and lead are pernicious; but iron and earthen ware are safest either on sea or shore.

In order to render the book as useful as my zeal has intended, I recommend it a fair perusal, from the first page to the last; a book of this nature is apt to be looked into, only when advice is wanted: that method is wrong; and in such a case, the best book in the world is apt to mislead. It is not enough that we know what we are to do with such and such disorders, but we should previously know what the disorder is; and how shall we know that, without having some idea of the evil before it comes on?

A book of this size is soon perused; taking a lecture or a section at a leisure time on board, will soon send the reader through the whole; and I flatter myself, that one perusal will lead to the second, when then it may be referred to for advice with safety; and I hope a study so essential to self-preservation, will be viewed in a more agreeable light, than it has hitherto been.

To compleat the whole, a copper-plate is annexed, wherein the most material utensils are exhibited, which was scarce capable to be explained by bare description, to men unacquainted with surgery.

To conclude, I must beg leave to observe, that the respect and esteem, with which I have been constantly honoured by every worthy seaman, whose life and health were committed to my care, have I confess, stimulated my endeavours, to offer them this book as a grateful return. And I am happy to reflect, that my experience in life enables me to make it worth their acceptance. May they reap that benefit from it, which my heart has intended them; and this is all the reward I wish to obtain.

N. D. FALCK.

ERRATA.[^[1]]

Page [5]. line 22. for cataplexy, read apoplexy. Page [6]. line 16. read, that a pressure on that part, not only occasions an apoplexy, but even stops life itself. Page [26]. line 17. for theirs, read thus. Page [35]. for Sect. vii. read viii. and following ix. x. Page [61]. line 4. for five or six, read about four or five. Line 21. for iniform, read inform. Page [91]. line 18. read, in order to get into. Page [131]. line 29. for purify, read putrefy. Page [135]. line 12. delete them. Page [142]. line 2. from the bottom, read, and is a sufficient. Page [158]. line 6. for malignitus, read malignities. Page [239]. line 7. read, the patient when not able to crawl to the tub, so revived &c.

[1]. These errors have been corrected for this ebook (May, 2019).

To the BINDER.

The Copper-Plate and its Explanation are to be placed at the End of the Book.

THE
CONTENTS.

LECTURE I.

An anatomical and physiological description of the human body

LECTURE II.

On the requisite means and medicines towards restoring health.

LECTURE III.

On accidents, and their proper method of treatment

LECTURE IV.

On external diseases, and their cure

LECTURE V.

Of fevers and inflammatory diseases, and their proper method of treatment

LECTURE VI.

Of the various internal diseases, and their method of cure

LECTURE I.

AN

Anatomical and Physiological Description

OF THE

HUMAN BODY.

The mechanism of the human body is so wonderfully, so curiously, and so wisely contrived, that the more we examine it, the more we must with admiration acknowledge, that nothing but an Almighty Being could be its author. This incomprehensible Being let us ever remember to reverence and adore, when we examine into the stupendous contrivance of our fabric; HE is the fountain, the benevolent upholder of nature, and all the creation; in whom we live, breathe, and have our being.

SECT. I.

Of the Composition and close Connection of Parts in the Human Body.

The human body is composed of solids and fluids; these are so closely, and so intimately combined with each other, that we find upon a physical enquiry and examination, they are scarce separable. They aid and give action to each other, and life depends not on each singly, but on the united, and on the separate spur, and on the soul of activity each gives to the other: Their substances form the body, and their action produces the operation of the mind.

Whilst every thing moves free and agreeable to the talk prescribed by nature, the automaton is in a state of health; body and mind enjoy peace and tranquility. So closely are body and mind in the most perfect bond of friendship, that they share pleasure and pain sympathetically with each other; and reciprocally contribute to each other’s welfare.

With what satisfaction is the mind continually engaged to give pleasure to the body! and with what alacrity are for ever the Members ready to obey the will! Happy harmony, by which we so wonderfully exist!

The solids are the canals and springs of life, and the fluids, which circulate in those canals, nourish them, and set the springs in action.

By the solids we understand,

1st The bones; the frame and support of our wonderful structure.

2dly. Gristles or cartilages; which cover the ends of the bones, in order to make them move with ease and agility.

3dly. Muscles; the fleshy parts, which by a nervous sensation, are induced, either voluntarily or involuntarily, to contract or dilate themselves, in order to give motion to the various parts of our body, to which they are fastened or destined to move.

4thly. Tendons; the chords as it were, by which the muscles are fastened to the bones, so as to make them follow the contraction of the muscles.

5thly. Ligaments; the chords by which the bones are connected with each other, and which give a firmness to their contact and articulation.

6thly. Arteries; the canals which transport the blood from the heart, to all the parts of the body.

7thly. Veins; the canals which carry the blood from the remotest arteries (in the most minute parts of the body) back again to the heart, for a new rotation of the blood.

8thly. Lymphatic Vessels; which are small cellular canals, that convey the lymph in different parts of the body.

9thly. Glands; which are kernels formed to secrete or separate various humours from the blood.

10thly. Nerves; these are medullary branches springing from the brain, and distributed in the most minute parts of the body; ordained to give the act of sensation, as the soul of animal activity.

11thly. Hair and nails; these are a horny substance, and appropriated either for defence or warmth of the different parts where they are placed.

The fluids; are, 1st. Blood; which is circulated in the arteries and veins, and is the nutriment and source of life.

2dly. The different humours separated by the glands from the blood; of which there are many, as the lymph, serum, spittle, seed, chyle, urine, gall, &c. appropriated to different uses, as hereafter will be described.

3dly. Fat, and marrow in the bones; which are designed not only as a store of nourishment, but to lubricate and warm the parts where they are lodged.

These are the principal materials which compose our wonderful machine. There are various other parts mentioned by Anatomists, both solids and fluids; but as this is designed only to give a universal idea of the most material parts of the structure of this stupendous fabric, we will let this definition suffice, and now consider with what order the principal organs of life act, either in consort, or in opposition to each other.

SECT. II.

Of the Brains and Nerves.

The brains are by all Physiologists esteemed the most mysterious organs of life, being the fountain of the nerves, the organs of sensation, and hence allowed by all to be the seat of the soul, or the sanctum sanctorum of the human understanding.

They are distinguished into the common or great brain called cerebrum; the small part called cerebellum; and the spinal marrow, which projects down the back-bone. The great brain is divided into two great lobes, seated in the upper and fore part of the skull, of which it takes in the greatest cavity. It is so exceedingly sensible, that the least pressure puts an immediate stop to the sensation of the animal; and which is generally termed a apoplexy.[^[2]]

[2]. Hence in a fracture of the skull, or any other heavy contusion, where the brain is compressed either by the fractured bone, or the extravasated blood, the patient will remain in a state of stupefaction, till either the fracture is reduced, or the extravasated blood removed by trepannation; after which he immediately comes to himself, as if suddenly revived from a trance.

This part of the brain, though it is so exquisitely sensible, seems to be designed by nature as preparatory to the cerebellum, the immediate root of the nerves.

The cerebellum is the lesser, but the more material part of the brains. It is seated in the hinder cavity of the skull, (which for the sake of protecting this exquisite sensible organ, is remarkably strong and firm) and from thence as the fountain of life itself, the nerves, the instruments of sensation in the whole animal frame, take their commencement: For whereas the other is so sensible, as that the least pressure will cause a stupor; this is so far superior in point of exquisite sensibility, that a pressure on that part, not only occasions an apoplexy, but even stops life itself.

From this cerebellum prolongates the marrow in the back-bone, called medulla spinalis, which is but a continuation of the same, and is equally sensible, and of the same substance with the former.

The whole brain, that is, the great brain, the small brain, spinal marrow, together with all the nerves which spring from thence, are covered with two coats, called the external stronger coat, dura mater; and the thinner and inner coat, pia mater; which continue with each nerve, even to its smallest ramification. The whole in a living subject is in a continual motion peculiar to itself.[^[3]]

[3]. This motion in the brain is not unlike the peristaltic motion; this is an observation too seldom taken notice of by anatomists, though evidently plain in living animals, and is of singular service in physiological enquiries.

From the cerebellum, and medulla spinalis, all the nerves take their commencement and origin. Ten pair spring forth from the part in the skull; the principal are those which form the various senses, tasting, smelling, hearing, and seeing, and that common to all, feeling. From the medulla spinalis, or marrow in the back-bone, proceed thirty pair of nerves, which spread themselves variously over the whole system.

All nerves have this in common with each other, namely, exquisite sensibility; but in other respects they differ however widely; particularly the nerves destined for some of the external senses.

It is from that common quality feeling, that they become the subtile springs of life; and give an edge to all the animal functions.

There is nothing so plentifully, and nothing more curiously interwoven with every other substance, as the nerves; and so amazingly quick is their sensation, that the very instant a single nerve, even the smallest and remotest in the system, is affected, the soul, or the common sensorium, is sensible of the identical part so affected.

It has been asserted, that this amazing quick conveyance of the sensation of the nerves, is owing to a subtile nervous fluid; but on a rational reflection, and a just enquiry into the animal œconomy, it must appear, that such conveyance of a fluid is inconsistent with probability and experience: For, neither are the nerves tubulous, nor has there ever been discovered any circulating humour in them. And secondly, is it consistent with reason, that a conveyance of a fluid from the toe to the finger, should be so momentarily quick, as is sometimes experienced in the gout, and other the like ailments? That the quick transposition of sensation of the nerves, is rather effected on a principle of vibration, appears more probable, and will admit of a more convincing experiment; which may be exemplified in the following manner: Suppose (in the language of a seaman) a rope runs from the top-mast-head, or any other part of the rigging, to the deck, and is kept tought and free from any interception; then it will be evident, that the least touch at one end will instantaneously be conveyed to the other end; in like manner the nervous sensation may be communicated, perhaps not unlike electricity; which similarly will in an instant be conveyed to any part, by a direct communication, but equally subject to be intercepted.

Hence, a paralytic limb will lose, together with its irritable sensibility, its circulation of fluids, and its nourishment; and recover again when the pressure or interruption is ceased. Hence also, spasmodic contractions will be affected at the irritation of some principal parts, and from this instantaneous irritability, the motion of every part is thought to obey the will.

SECT. III.

Of the Heart and Lungs.

The heart is a muscular body, situated in the breast or chest, somewhat between the lobes of the lungs, and formed by nature to be the principal organ for the circulation of the blood and other fluids.

Its structure is wonderful, and of a most curious piece of mechanism. It has two principal cavities, called ventricles, which are separated length-ways by a wall, and distinguished into the right and left.[^[4]]

[4]. They might with equal propriety, be termed anterior, or foremost, and posterior or hindermost.

Each of these cavities or ventricles, have particular valves, call’d ears, or auricles; which perform the function somewhat similar to the suckers of a pump: By these contrivances the heart receives the blood from the veins, and expels it again by the arteries, to every part of the human body; in a manner that I shall hereafter describe.

The lungs are organs immediately concerned in the circulation of the blood also; their function is to receive the air, to purify it, to circulate, and to distribute it in due proportion in the sanguineous mass, and to extract and expel that part of air already made use of; and thus act the part of ventilators in the animal œconomy.

They are divided into two lobes. These lobes are a continuation of little bladders, that have an immediate continuation with the wind-pipe, aspera arteria. The wind-pipe from the larynx down to the very lungs, is protected externally with semicircular gristles, in order to keep it always open, and so shelter it from external injury; when it enters the lungs it spreads itself into numberless branches like a tree, and sends ramifications into every little air-bladder in the lungs.

All along these ramifications and the air-bladders, are arteries, veins, and lymphatic vessels, which have an immediate communication with the heart, by means of the pulmonary arteries and veins.

Now at the instant of inspiration, these little bladders in the lungs are filled with air, which infuses itself by the small arteries into the whole mass of blood; and at the expiration again, the air which has been made use of, and drawn from the neighbouring little veins, is again expelled by the wind-pipe through the mouth: And thus is respiration performed by alternate motions of the lungs; receiving the fresh, and alternately expelling the foul air again; thence justly may they be deemed the ventilators of the human automaton, and a principal organ of life, in the animal creation in general.

The upper part of the wind-pipe, which is in the fauces of the mouth, is called the larynx. This is the organ of voice.

In this animal mechanism is contained, all the variety of formation requisite to every kind of sound that can be performed upon any instrument whatever. Its parts are chiefly of a gristly substance, at the same time exquisitely delicate, with nerves and glands; from whence it is subject to diseases on the slightest indisposition.

In men it is larger than in women; hence their voice is rougher; which generally increases by exercise of the voice also. Its formation is very complex, and too tedious here to enter upon; we will therefore pass it over, and hereafter say as much as relates to its preservation, and giving it relief when disordered.

SECT. IV.

Of the Circulation of the Blood.

We shall now consider the circulation of the blood; the grand source of our existence. At the contemplation of which we must be lost in admiration, at the wonderful wisdom of its contrivance; and with uplifted eyes adore the cause of its motion!

The Heart, as I before observed, has two chambers or ventricles, distinguished by the right and left; each of these chambers have also a valvular cavity call’d auricle, or ear. Each ventricle opens itself into an artery and auricle; and each auricle opens itself into a ventricle and vein. These openings have valves, which open and shut alternately, and by this, prevent any confusion or hindrance in the influx and efflux of the blood.

The right ventricle is the longest and greatest, but weakest: From this ventricle springs forth the pulmonary artery, which spreads itself throughout the Lungs.

The right auricle is also the largest; in which opens itself the large vein, called vena cava; as the common trunk that receives the blood from all its branches spread over the whole human body.

The left ventricle is shorter, but the walls are considerably stronger than that of the right ventricle. Here begins the aorta, or the great artery, by which the blood is sent to all the parts of the human body.

The left auricle is also somewhat smaller than the right; and in that opens itself the pulmonary vein, which returns the blood from the lungs, after it has received its necessary assistance from the vesicles of air in the lungs.

This premised and understood, the circulation is performed in the following manner:

The right ventricle being full of blood, contracts itself. This contraction is called the systole, by which it forces the blood through the pulmonary artery into every part of the lungs, even into every vesicle; where it receives a portion of the air, drawn in by the wind-pipe.

At the end of these arteries join the ramifications of the pulmonary vein, which receives the blood from the ramifications of the arteries, by anastomosation; which, by little quantities, these veins gather gradually into little branches, and at last become one common trunk, which empties the blood into the left auricle of the heart.

From the left auricle it is let, by means of a peculiar constructed valve, into the left ventricle; which, by a dilation called the diastole, receives it from its auricle.

Immediately upon this reception, the systole or contraction takes place, and the blood is forced into the great universal artery, aorta; by which it is farther transported into every part of the human body.

This artery spreads as it goes, and continually decreases in magnitude, as it becomes numerous in branches; until it terminates into the smallest ramification in the remotest part of the body.

The systolic contraction, and the diastolic dilation, which alternately take place in the heart, continue throughout the arteries from the great trunk to the remotest capillary ramifications,[^[5]] by which means the blood is transported with more certainty and facility to the minutest part.

[5]. Concerning this great act of continued systole and diastole, Anatomists have greatly varied; but from the structure of the arteries, and the continued pulsation, this way of transporting the blood is confirmed both by reason and experience.

At the extremity of these arteries the veins take their commencement, in ramifications equally small with the former; these take up the blood from the arteries, by many infinite small quantities, and carry it gradually back from those extremities to the heart again, for a new rotation.

These veins commencing infinitely small, but gradually gathering, become branches, and at length form one general trunk, called the vena cava, (or the great universal vein); and this empties itself again into the right auricle; from whence it is let again into the right ventricle, whence it came; then again forced into the lungs; thence back again into the left ventricle; from thence all over the whole body, and continues the Circulation.

SECT. V.

Of the Joint Connection of the Brain, Heart, Lungs, &c.

These are the principal actions in the grand movement of the human automaton.

The nerves are the subtile springs of the sensation, by which the whole becomes sensible of irritation, and agitated to its functions. Their ramifications are extended ad infinitum, and so curiously distributed, that though there is not a part in the whole system exempt from their spreading, yet they are distributed with such regularity, that they don’t interfere with each other. A regularity absolutely requisite to the order in the animal œconomy: For whereever the vibration of the nerves is obstructed, life or motion must in consequence cease.

The lungs are the ventilators in the system: they receive and let in the air; they sift it from all its gross particles, and extract the useful parts from this universal element of life; thus they give from every little vesicle, a due proportion of extracted air to the blood by the adjacent veins; and by the neighbouring arteries, again extract the foul air from the circulated blood, which by the mouth and nostrils is expelled again; at that instant a fresh quantity of air is drawn in again for a new supply.

Thus by intervals, the lungs, like a perfect ventilatory machine, repeatedly, and without intermission, keep time with systolic and diastolic motions of the heart, in exchanging fresh and foul air for the support of this wonderful animal structure. This is the function of breathing respiration, namely inspiration, or the drawing in the fresh air; and expiration, the expelling the foul air.

The heart may be considered as the grand perpetual pumping engine, constructed on principles, so as to have the least friction possible.

This curious pump, the heart, sends the fluid of life, the blood, to all the parts, even the remotest in the whole machine. The arteries are the canals of the conveyance; they are strong elastic tubes, whose fibres are of spiral direction, and receive from the heart a power of contraction; which is continued from the heart in the moment of the systole, even to the remotest and most minute ramifications; by which the blood is pushed along to the minutest extremities. This is immediately succeeded with a diastolic reception of a fresh quantity of blood; so that on succession, the diastole and systole is perpetuated not only in the heart, but throughout all the arteries, in a friendly correspondence over the whole system: And this constitutes the pulse.

The veins, however, are somewhat of a different texture from the arteries; whilst the arteries transport the blood by an elastic and pulse-like contraction, the veins on the contrary, receive it from them at the extremities, in an easy and imperceptible gradation; for whereas the fibres in the arteries are in a spiral direction, elastic and strong, the coat of the veins are tender, and the fibres more longitudinal.

Hence, the wounds in the arteries and veins differ greatly; for whilst the arteries are for ever in a strong agitation, the veins perform their functions with less exercise; and therefore the wounds in arteries are always attended with danger, whilst the veins heal easy. From the same reason also, the arterial blood differs from the venal; for as the arterial blood is sent to all the Parts, as the grand nutriment, from whence the glands secrete their peculiar humours; the veins only transport it back again, to prepare it for a new rotation. Whence the blood in the arteries is of a high colour, and of a more alkalascent nature, than that in the veins.

Collateral with the minute ramifications of the veins and arteries, over the whole system, are the lymphatic vessels, which separate from the blood as it passes along, a transparent lymphatic humour, adapted for the different parts, which they are connected with.[^[6]] These vessels are materially different, from either arteries and veins in their structure, and justly to be compared to a continuation of little cells; so constructed, as to transport the humours, without admitting a return.

[6]. An opinion has lately been broached, that the lymphatics are all absorbing vessels, of the same nature with the lacteals, and that they all join to empty themselves in the subclavian vein to the common mass of the blood; but this to me, seems too general, and contradicts experience.

From hence we see plainly how these three organs, the brains, the lungs, and the heart, are concerned, and mutually assist each other in the actions, and circulation of the fluid of life; nothing could move without the sensation of the nerves; these could not exist without the blood, from which they receive their support; the blood could not circulate without the heart, arteries, and veins; and in them it could not move with a necessary freedom, except its being supplied with a sufficiency of air from the lungs: So that evidently all three are so interested in this grand movement, that the stopping of the one, must needs be the stopping of the whole.

SECT. VI.

Of Chylifaction and Nutrition.

In the preceding we have briefly considered the state of the fluid of life, and mechanical instruments of their motion in the human machine. In this we will consider how the whole is supported, and the vital lamp, from time to time, becomes supplied.

Under this consideration we will examine the canal of food, and the various changes the morsel undergoes from the time we take it in our mouths, till the nutriment is reduced to blood, and the remaining dross is expelled the body as useless.

The animal functions towards chylifaction and nutrition, are mastication, or chewing the food; deglutition, or swallowing; digestion; chylifaction; nutrition; and the excretion of the fæces.

In order therefore to understand this clearly, it becomes necessary to describe the organs which nature has formed for the requisite performances thereof.

In the first place then, smelling is that sensation which nature has given to every animal, that has a choice of food, as the first safe-guard to inform it of any thing agreeable or disagreeable, useful or pernicious to its body; its seat is in the nose chiefly, but we find by experience, that it has a friendly connection with our palate and stomach; for the effluvia of any thing will either create a desire, or give us the greatest aversion to every substance that throws out a flavour.

It is performed by means of a subtile spreading of nerves, peculiarly delicate; which continues through the membrane of the nose, the roof of the mouth, gullet, and the very stomach.

Taste is the next sensation, which nature has given us, not only as a distinguisher of proper food, but a sensation from which we receive many luxurious pleasures; and to the indulgence of this sensation, most evils and plagues to mankind, take their origin.

The tongue is the principal instrument of that peculiar quality; but if we examine somewhat closer into this affair, we shall find that the soul of pleasure and pain of that sensation, as well as that of smelling, has its seat in the stomach; for that which will taste pleasing and good at the first approach, will soon lose its relish when the stomach is gratified: and, if any thing tastes disagreeable, the stomach receives it with reluctance, and will ever incline to discharge it again.

The tongue is an instrument (if I may be allowed the term) very curiously constructed; it is moved by a variety of muscles, and serves not only for tasting, but also as a labourer, to shovel and to turn our meat between our grinders; so that nothing may escape being well masticated, and intermixed with that fine digesting balsam, the spittle, in order that it may be easily swallowed.

Besides this, it makes the most requisite instrument for the noble and excellent faculty of speaking; which forms one of the principal characteristics that distinguishes man from the brute creation.

The gullet or oesophagus, is the canal which conveys drink and food from the mouth to the stomach; this canal is a muscular, tendinous, and vascular tunic.

The commencement of it is in the mouth, and is called the pharynx; a curious structure, that receives the food, and by its contractive motion, and the help of the tongue, forces the aliment into the stomach.

The stomach is much like the bag of a Scotch bag-pipe; it lies immediately under the diaphragm or midriff, covered partly on the right side with the liver, and on the left side with the spleen. The left and superior part, is continued with the oesophagus; and the right and inferior part, or orifice, commences the intestines.

The first orifice is called the mouth of the stomach; and the second the pylorus, or porter: At the porter there is a curious valve which lets the aliment out by small parcels into the intestines, where it undergoes its various other changes.

The stomach has three teguments, a muscular, a tendinous, and nervous coat; this nervous coat has another slimy one, but this in reality, is a delicate lining, interwoven with nerves, and the ramifications of fine blood vessels.

The intestines or guts, are a continuation of the stomach, they are a canal which is generally reckoned six times as long as the subject it is taken from; it is distinguished in small tenuia, and wide crassa.

Each again is divided into three parts: the tenuia, or small narrow intestines, are the duodenum, or twelve finger-gut; the jejunum; the ileum: The wide or crassa, is divided into the cæcum; the colon; and the rectum.

Throughout the whole canal of intestines are numbers of little vessels, called lacteals, which lead the chyle, extracted from the aliment, into a receptacle, which is lodged in the mesentery, and from thence, by another duct call’d the thoracic duct, is carried along the back-bone upwards, and joins to the left subclavian vein, where the chyle gradually commences to be blood.

This short description we will let suffice, and now enter upon the action itself.

The morsel now, which is designed for food, is taken into the mouth, masticated with the teeth, turned about with the tongue; and as the mouth is at work, the saliva or spittle is squeezed from the salival glands, and thus intermixed with the aliment; when enough chewed and moistened with this saliva, it is conveyed to the pharynx, or swallow, which receives it, and, by its contraction, forces it into the oesophagus; and by a repeated contraction, is carried down into the stomach.

There it is again moistened with saponaceous liquid, or pancreatic juice; by which and by a perpetual motion of the stomach, it is brought into a state of digestion; then by small degrees entered through the pylorus or porter, into the first division of the gut, the duodenum.

This gut is about twelve fingers long; and whilst the aliment is there, it is intermixed with the gall, which is a liquor separated by the liver, and contained in the gall bladder; this liquor, the gall, is carried into the duodenum, by a small duct, called the ductus cysticus; where also enters another kind of liquor called the pancreatic juice.

When the aliment is thus prepared, and fit for a particular state of dissolution, it is carried into, and through the jejunum. This gut is in length about twelve or thirteen hands breadth, and its motion somewhat brisk; through which the aliment passes pretty quick, and hence, generally is somewhat empty.

As it passes through this part, the chyle is separated from it by the lacteals, which are small vessels that separate the chyle from the aliment, and abound there more than in any other part of the gut.

From thence it comes into the ileum; that is the longest of all the divisions of the guts, and is in length about twenty-one hands breadth; it has a great many circumvolutions, and next to the jejunum, has many lacteals to separate the chyle.

Now the aliment comes into the wide gut, and gradually becomes fæces; and first, the cæcum: This part is rather an appendix only, and hangs from the main part like a finger to a glove. The use of this gut has been much controverted by anatomists; it seems however, very probable, that this appendix is designed to keep the aliment in for further digestion, as it now begins to putrefy, and becomes fæces or excrement.

From thence it enters the colon, which is a long, and very winding intestine; it runs up along and about the liver, touches the gall bladder, and the spleen; from thence it descends again to the os sacrum. It has but few lacteals, and is, as it were, the last drainer of the fæces: It is this intestine which is the seat of the Colic, and of most other complaints of the belly.

Next to this comes the last and straightest, the rectum; this gut is closely adherent to the sacrum, and ends in the fundament; which is provided with muscles to open and shut the anus, in order to contain the fæces, and discharge it.

The mechanism of chylifaction in the human body differs from the brute creation in general, except that most contemptible of the whole, the hog; to which it bears a very near resemblance, insomuch that there is very little distinction.

Both have that advantage over the generality of terrestrial animals, that they are confined to no particular food; which favours greatly the luxury of the one, and the beastiality of the other.

The brute creation are generally distinguished into carnivorous and granivorous: The first is that kind which feeds upon flesh; and the latter upon grain and vegetables. Upon examination however, we find, that the stomach and guts are peculiarly adapted to their food; and that grass agrees no more with the dog, than mutton does with the horse.

But man is so happily made, that any thing which is food, is proper for him, and he may become used to it; and thus is either carnivorous or granivorous.

The whole canals, from the stomach to the anus, is in a continual vermicular motion, which is called the peristaltic motion; by this the aliments are dissolved, and disunited; and as they pass along, are drained by the lacteals, of their nutriment or chyle.

These lacteals are, by means of a membrane (with which they are surprisingly interwoven, and connected to the whole canal) called the mesentery, lead regularly into one common cistern, lodged almost in the middle of the intestines, in that membrane, called the receptacle of chyle; and from thence the chyle is carried by a duct up along the back-bone, called the ductus thoracicus, into the left subclavian vein, where it gradually commences to be blood.

By this mechanism we are nourished, and the substance of our food converted into blood, and transported through the whole animal machine, for the support of every part of its wonderful composition.

As all animals which feed upon flesh, are more subject to diseases, nature has provided them with these advantages: that when any thing is obnoxious to their nature, and received into their stomach, or their being over loaded, it can discharge itself of so troublesome a burthen, by vomiting, which is effected thus: when the inner coat of the stomach, which is irritable and nervous, is stimulated by whatever is obnoxious, it will cause in the whole stomach, a contraction; and by that, force its contents to the shortest direction of evacuation, namely, by the canal of the oesophagus, through the mouth. This expulsion is peculiar to carnivorous animals only.

Purging or discharging by the fundament is common to all animals of whatever kind; and is performed by an irritation in the intestines, by which the peristaltic motion is increased; to this I must add a reversion of the secretion of the lacteal vessels, by which the humours are increased, the motion accelerated, and the fæces discharged, without giving any nourishment to the body, and consequently the system diminished.

Digestion is that act by which the aliment or food is prepared, so as to produce a good chyle, and consequently good blood, for the nourishment of the body. Though no animal has a more delicate stomach than man, yet it must be observed, that none has a stomach better adapted for all kinds of food.

Whence therefore in the common course of life, temperance and gentle exercise is what nature requires to maintain health. But nothing becomes more obnoxious to that blessing, than gluttony, voluptuousness, and idleness.

SECT. VII.

Of the Bones, Muscles, Ligaments, Tendons, and their Connections.

The bones may be considered as the timber-work of the human frame; by which this wonderful fabric is supported, and kept in its due form, that the whole may be brought into its various movements, without confusion or obstruction to each other.

The bones are the most solid parts of the human body, composed of hard and indurated fibres, striated over each other, in a manner peculiar to that substance. The bony fibres are in themselves insensible, yet as the parts are variously distributed with arteries and veins, and that the nerves must necessarily have a share in their formation, they have a peculiar sensibility, which is perceptible in some parts more than others; they cannot strictly speaking, be deemed quite insensible.

The whole bony frame is covered with a tendinous and nervous tegument, called periosteum; except such parts of the teeth as are designed for mastication, which are provided with a peculiar enamel, that is harder than the rest of the bony substance.

The periosteum is exquisitely sensible, and is the safe-guard to the substance of the bone, which is delicately tender notwithstanding it is not so sensible as the skin that covers it; insomuch that it will become carious on the least exposure to the air, or the attack of any foreign body of matter whatever; whence in wounds and fractures in general, great attention should be paid to the substance of the bone, being very subject to become carious and to exfoliation, which is of the greatest consequence; but of this I shall say more in another place.

The marrow is principally designed for the nourishment of the bones; which is evident from its being plentiest in young people, when the bones are strongest; and that when it is deficient, they become brittle, and lose their tenacity.

The marrow is contained in a cellular substance, partly in vesicles of a nervous texture, and partly bony cells. At the ends of the long bones the texture is more spungy than in the middle, where the cavity is less, but the substance is most compact. Though anatomically there is no perceptible circulation in the bones, yet, that a circulation is actually existing, is evident, from a liquor oozing out from the ends of a fractured bone in the living animal; by which a fractured bone again unites, and this is called the callus; and whilst in its liquid state, resembles the white of an egg, which gradually ossifies, and becomes as hard as the main substance of the bone.

The number of bones differ somewhat in various subjects; ordinarily they amount to two hundred and fifty-two: In the head sixty-three; in the trunk seventy; in the arms and hands sixty; and in the legs and feet sixty.

As the bones are the support of the animal fabric, I have inserted in the next page, a catalogue of the human skeleton, which occasionally may be referred to:

A Skeleton of the Human Body.

Bones in the Head.

The Skull.

The Forehead.

The Hindhead.

The Sides of the Head.

The Temples.

The Basis of the Skull.

The Bones of Hearing.

The Face.

The Upper-Jaw.

The Under-Jaw.

The Teeth.

The Tongue-Bone.

Bones in the Trunk.

The Spine.

The Ribs.

The Shoulders.

The Hip and Bason.

The Breast.

Upper Extremities.

The Upper Arm.

The Under Arm.

The Wrist.

The Hand.

The Fingers.

Under Extremities.

The Thigh.

The Knee Pan.

The Leg.

Ancle.

Foot.

Toes.

The connection of the bones are in various ways; those connections that are designed for rest, are by close contact of parts, and are called sutures or seams; such are the bones of the skull with themselves and the face. Those connections which are designed for motion are called articulation. Some of the articulations have but an obscure motion, as the ribs with the back-bone, and the back with itself, &c. Others have an angular motion, as the elbows and knees; and others again have an universal motion, as the arm-bone with the shoulder, and the thigh bone with the hip. The sutures, and such connections as have no motion, are merely dovetailed into one another in close connection; but those articulations that are designed for motion are connected by cartilages, either in close contact, or so as to move slippery over one another.

The ligaments are those tough tendinous parts, by which the articulations designed for motion are joined together; at some parts they cover the joints only, and at others, they are immediately fastened to each other, besides the external coverings; those ligaments are very strong and elastic, and have a close connection with the nerves that pass by them.

The surrounding ligaments of all moveable joints, form a capsular-bag, which contains a slippery liquor, called synovia, that lubricates the ends of the bones covered with cartilages, that they may move with ease and agility over one another.

Muscles are the fleshy parts on the human body, appointed for motion. They are a composition of arteries, veins, nerves, and tendons.

Muscles are generally divided into two kinds; those for necessary or involuntary motion, and those for voluntary. Some again are fastened at each end to some of the bones at their extremity, and contract themselves in a straight direction; others again are annular, or in the form of a ring; and by this manner open and shut. The first kind are generally divided into three parts, the head, belly, and tail. The whole muscle begins and ends in a tendon, by which it is fastened to the part it is designed to move; which, when the belly of the muscle contracts itself, must consequently draw both bones nearer together, fastened to the head and tail; and thus performs the motion. Some of these muscles act in consort, and others in opposition to each other.

The tendons are the principal parts of the muscle; and that part thereof, as before observed, which is fastened in the bones, namely, at the head and tail of the muscle, and is the chord, as it were, by which the limb is brought into motion.

A tendon is a hard, substantial, flexible, and elastic body, which, at the head of the muscle, is very compact; but as it enters the muscle, spreads its fibres over the whole body, gathers again at the tail, in as compact a manner as it began, and continues in this chord-like texture till it fastens itself at its appropriated place.[^[7]]

[7]. It must be observed however, that tendons take on many various forms, as different as the muscles; which would be too tedious here to particularize.

The tendons and ligaments are of equal substance, and differ in nothing but their various uses; namely, the ligaments to connect the articulation; and the tendons, or the ends of the muscles, to give motion. The muscles are a composition of the tendinous fibres, plentifully intermixed with small ramifications of blood vessels; all which compose the fleshy part thereof. Hence, the tendons being white and hard, the muscles gradually grow softer and redder in the middle of them; and they verge gradually to become tendinous at the tail, the same as the head.

Hence, from the close texture of the tendons, they are very painful when wounded, or otherwise hurt; but as the muscles are softer and more pliable, their wounds and other accidents are of less consequence, and not so dangerous as the former.

The number of muscles are undetermined, for though the principal muscles are so distinct that they cannot be mistaken as to their form and use, yet there is so great a number of small ones, or so many of the great ones capable of being subdivided again, that anatomists have not, as yet, agreed about their number.

SECT. VIII.

Of the Urinary Organs and Genital Parts.

The kidnies, the ureters, the bladder, and the urethra, are the principal urinary organs. The kidnies receive two arteries called the emulgent arteries, from the great arterial trunk, called aorta, before described; they each send also two veins back again, accompanying the arteries to the vena cava. Whilst the blood is circulated in the kidnies, the urine is secreted in many small quantities, and carried from each kidney by a tendinous tube, the bigness generally of a small goose quill, called the ureter to the bladder. The ureters enter the bladder between its lamillas, so as not to admit of a return. Hence, a bladder in its natural position is both wind and water tight, and if reversed, is neither.

The bladder of urine is of a tendinous and nervous texture, and capable of great extension, but at the same time exquisitely sensible. The neck of the bladder is very muscular, and by this forms a sphincter, or annular muscle, by which the urine is retained; and as it is of a very sensible nature, this part is subject to inflammatory constrictions; great pain, and many evils have there been occasioned, either from venereal cases, or gravelous complaints.