IN order to shew how persons recover out of a fit of this Disease, by the mere efforts of nature, I shall beg leave to premise a few of the most probable opinions, and best establish’d propositions, concerning Animal Motion, which I shall here take for granted, and refer the reader, for a physical demonstration of them, to the ingenious Essays of Doctors Porterfield, Whytt, Simson, and Haller.
Animal and Muscular Motion is said to be of two kinds, viz. Voluntary, and Involuntary or Habitual.
By Voluntary Motion is meant the action of any Muscle or Muscles produc’d by an immediate or conscious determination of the Mind; of this kind are the several occasional motions of the Body.
Involuntary or Habitual Motions are such as proceed originally from the Mind also, but are so establish’d, by long custom, that the Mind is not immediately conscious of them, nor can stop them at pleasure13. To this class, the Motion of the Heart, the peristaltic Motion of the Stomach and Guts, Respiration, and several Motions of the Eyes belong.
The vital Motions are suppos’d to be continued by a stimulus constantly applied to the Fibres of the Muscles which perform them.
Hence the Ventricles of the Heart are constantly irritated and stretch’d by the Venous Blood, which brings them into contraction, to propel the Blood through the Body.
Thus the Alimentary Tube is mov’d by the irritation of the food, rarefied air, &c.
And in like manner respiration is carried on, by the uneasiness that is felt in the Lungs at the end of every dilatation and contraction of the Thorax, which is owing to the resistance that the Blood meets with, both from the collapsing of the Lungs, and from the pressure of the rarefied air on the small Pulmonary Vessels, during their expansion: to which may be added, the elasticity of the Cartilages.
These several stimuli can only be perceiv’d by a sentient principle, which, in the human species, is call’d the Soul.
When the Soul is first united with the Body, and receives command over the organs of Motion, it seems to have been laid under a kind of necessity, by which it is compell’d to exert these organs in avoiding whatever is hurtful, and in chusing whatever is apparently beneficial, to the Body.
’Tis evident, from the laws of the Circulation, that when the Motion of the Blood through the Lungs is stop’d, for a short time, the right Ventricle of the Heart must be violently distended, and consequently severely stimulated. This strong irritation may bring the Ventricle into a vigorous contraction, which is all that is wanted to put the admirable machine again in motion; for, as soon as the right Ventricle discharges itself into the Pulmonary Artery, ’tis plain, from the laws of hydraulics, that the Blood must move in the Pulmonary Veins; and therefore the pressure on these vessels must be overcome. Thus the circulation of the Blood will be renew’d, and the vast distention of the vessels about the Heart, will rouse the attention of the Mind to change the uneasy position of the Body as soon as possible; which will alter the direction of the Heart’s center of gravity, and therefore take the pressure off the Pulmonary Veins and inferior Auricle, and by that means afford a free passage to the Blood through the Lungs. In this manner people may recover, without any external assistance.
’Tis highly probable that the Motion of the Blood is renew’d before any of the Voluntary Motions are recovered; for we never find that any of the Voluntary Motions remain after the Motion of the Heart ceases; and the surprising process of generation shews, that the first Motion observable in animal Bodies, is that of the Heart14. We have many instances, in Brutes, of the Heart’s Motion continuing long after the action of the Voluntary Muscles is quite de stroy’d15. It is not improbable, that the human Heart would contract itself after Death, if the same experiments could, with any degree of humanity, be tried on it, that are made on the Hearts of Brutes: and the great Lord Bacon gives an instance of a criminal’s Heart, which he saw, after torn from the Body, leap up and down for several minutes16.
In a severe fit of the Night-mare, when the Motion of the Blood, and consequently the Motion of the Heart, is stop’d, the Mind, must be in a terrible agony; and the only chance it has for further communication with the Body, depends upon the vigour and sensibility of the right or superior Ventricle of the Heart; for, if it be not able to push the Blood through the Lungs, and overcome its own weight at the same rime, de Vita Actum est.
From what has been said it appears, that lying on the Back is a dangerous, uneasy position, and should be carefully avoided, even when we are awake. I believe few can lie long on the Back without feeling an uneasiness in the Breast, which is soon remov’d by turning on either Side: but when People are buried in sleep, and are incapable of that action, the consequence is dreadful, for the reason often mention’d. We may be convinc’d, that, if lying on the Back would not impede the Vital Motions, nature would have directed us to chuse that position in sleep, because it requires scarcely any muscular action. But, on the contrary, we find that most of the human species prefer lying on either Side.
As colonel Townshend’s case is a remarkable instance of the dangerous effects which may proceed from lying on the Back, and as it may serve to illustrate my theory of this Disorder, I shall here quote it at full length, that the reader may the more readily observe the analogy between his mechanical suppression of the Vital Motions, and a fit of the Night-mare, It is thus related by Doctor Cheyne, in his English Malady17.
The CASE of the honourable Colonel Townshend.
“Colonel Townshend, a gentleman of excellent natural parts, and of great honour and integrity, had for many years been afflicted with a nephritic complaint, attended with constant vomitings, which had made his life painful and miserable. During the whole time of his illness, he had observ’d the strictest regimen, living on the softest vegetables and lightest animal foods, drinking asses milk daily, even in the camp: and for common drink Bristol-water, which, the summer before his death, he drank on the spot. But his illness increasing, and his strength decaying, he came from Bristol to Bath in a litter, in autumn, and lay at the Bell-Inn. Doctor Baynard (who is since dead) and I were called to him, and attended him twice a day for the space of a week; but his vomitings continuing still incessant, and obstinate against all remedies, we despair’d of his recovery. While he was in this condition, he sent for us early one morning: we waited on him, with Mr. Skrine his Apothecary (since dead also;) we found his senses clear, and his Mind calm, his Nurse and several Servants were about him.
“He had made his will and settled his affairs. He told us he had sent for us to give him some account of an odd sensation, he had for some time observ’d and felt in himself: which was, that composing himself he could die or expire when he pleased, and yet, by an effort or somehow, he could come to life again; which it seems he had tried before he had sent for us. We hear’d this with surprize; but as it was not to be accounted for from any common principles, we could hardly believe the fact as he related it, much less give any account of it; unless he would please to make the experiment before us, which we were unwilling he should do, lest, in his weak condition, he might carry it too far. He continued to talk very distinctly and sensibly above a quarter of an hour about this (to him) surprising sensation, and insisted so much on our seeing the tryal made, that we were at last forced to comply. We all three felt his Pulse first: it was distinct, though small and thready; and his Heart had its usual beating.
“He composed himself on his Back, and lay in a still posture for some time; while I held his Right-hand, Doctor Baynard laid his Hand on his Heart, and Mr. Skrine held a clean looking-glass to his Mouth. I found his Pulse sink gradually, ’till at last I could not feel any, by the most exact and nice touch. Doctor Baynard could not feel the least motion of his Heart, nor Mr. Skrine the least soil of breath on the bright mirror he held to his Mouth; then each of us by turns examin’d his Arm, Heart, and Breath, but could not, by the nicest scrutiny, discover the least symptom of life in him.
“We reasoned a long time about this odd appearance as well as we could, and all of us judging it inexplicable and unaccountable, and finding he still continued in that condition, we began to conclude that he had indeed carried the experiment too far, and at last were satisfied he was actually dead, and were just ready to leave him.
“This continued about half an hour, by nine o’clock in the morning in autumn. As we were going away, we observed some motion about the Body, and upon examination found his Pulse and the motion of his Heart gradually returning: he began to breathe gently and speak softly; we were all astonished to the last degree at this unexpected change, and after some further conversation with him, and among ourselves, went away fully satisfied as to all the particulars of this fact, but confounded and puzzled, and not able to form any rational scheme that might account for it. He afterwards called for his attorney, added a codicil to his will, settled legacies on his servants, received the sacrament, and calmly and composedly expired about five or six o’clock that evening. Next day he was opened (as he had or dered) his Body was the soundest and best made I had ever seen; his Lungs were fair, large, and sound; his Heart big and strong, and his Intestines sweet and clean; his Stomach was of a due proportion, the Coats sound and thick, and the villous Membrane quite entire. But when we came to examine the Kidneys, though the left was perfectly sound, and of a just size, the right was about four times as big, distended like a blown Bladder, and yielding, as if full of pap; he having often passed a wheyish liquor after his urine, during his illness.
“Upon opening this Kidney, we found it quite full of a white chalky matter, like plaister of Paris, and all the fleshy substance dissolved and worn away, by what I called a Nephritic Cancer. This had been the source of all his misery; and the symptomatic vomitings, from the irritation on the consentient Nerves, and quite starv’d and worn him down. I have narrated the facts as I saw and observ’d them deliberately and distinctly, and shall leave to the philosophic reader to make what inferences he thinks fit: the truth of the material circumstances I will warrant.”
In this gentleman’s case we may observe, that the contractile power of his Fibres was very much weaken’d, their sensibility in a great measure destroy’d, and his vital energy far exhausted, by the long and severe irritation in his Kidney; and that, when he composed himself on his Back, the motion of the Blood through the Lungs was easily stop’d, in the manner above-mention’d, viz. by the pressure of the Heart upon the left Auricle and Pulmonary Veins; to, which may be added, a small degree of volition in restraining the organs of respiration. In this dead state, we are told, he lay half an hour; in which time the greater part of Blood was drove into the Veins, as generally happens soon after respiration stops. Hence the right Ventricle must have been greatly distended and severely stimulated by the refluent Blood, ’till at length it was brought into a strong contraction, which put the Blood again in motion through the whole Body, and a small spark of vital vigour still remaining, continued it so for eight hours afterwards.
The Mind too, in this case, as in many others of the like kind, was probably tir’d of its communication with the Body, and was willing to take its flight from an habitation in which it felt so much pain.
I have offered this account to the curious, not because I think it altogether satisfactory, but hope, that its insufficiency may induce others to give one more adequate.
If colonel Townshend had not compos’d himself on the Back, could he have produc’d that surprising effect? If he had been turn’d on his Side, would he not have sooner recover’d? Were not the Doctors very blameable for offering to go away without using some means to recover him?
It is observable, that when People are far exhausted by Diseases, and are on the brink of dissolution, they generally lie on their Backs, because they have not muscular force sufficient to support the Body on either Side.
From what has been said concerning the supine portion of the Body, it appears, that it helps considerably to close this scene of life, by stopping the Blood in the Lungs. Hence the immortal Boerhaave observ’d, “18 Proximam mortis causam, et ultimum ferme omnium Lethalium morborum effectum esse Peripneumoniam.”
If then the supine position has such a remarkable effect in stopping the Motion of the Blood, and consequently in putting an end to this Life, would it not be prudent to turn People on their Sides, and keep them so, who are so far spent in acute Diseases, that, they are unable to poize themselves in that salutary position? Would it not be often a means of prolonging the fatal, and of promoting an happy crisis?
When the force of an acute Disorder, and the strength of Nature are nearly equal, would not the weight of the Heart cast the ballance?