7.*^. if jjSPt*'"^ : rV. ;, p **• -w *• m^ H %*. iT6-*|-3_ Surgeon General's Office LmMm* o 5W* C/icrtcu, J~" ..i '» ......... XoA / V^/ ~. O'O.QO, 0 ■laQCOO'QG'O GO /? 7T AN EXPERIMENTAL INQUIRY INTO THE PHENOMENA OF SUSPENDED ANIMAL LIFE, FROM DROWNING, HANGING, AND THE ACTION OF NOXIOUS AIRS; TOGETHER WITH THE MOST CERTAIN AND EXPEDITIOUS MODE OF RECOVERING ANIMALS IN THAT STATE. JWALD, BY JOHN OS^ gum OF COLLETON, SOUTH-CAROLINA; HONORARY MEMBER OF THE PHILADELPHIA MEDICAL AND CHEMICAL SOCIETIES. " Lateat Scintillula Forsan." s«-h PHILADELPHIA: PRINTED FOR THE AUTHOR, EY HUGH MAXWELL. 1802. AN INAUGURAL DISSERTATION, FOR THE DEGREE OF DOCTOR OF MEDICINE; SUBMITTED TO THE EXAMINATION OF THE REVEREND JOHN EWING, S. S. T. P. PROVOST; THE TRUSTEES AND MEDICAL FACULTY OF THE UNIVERSITY OF PENNSYLVANIA, ON THE 27th DAT OF MAY, 1802. '■*£.&. ^t^??rr y^* it is a fact, that the lungs may be inflated, and the pres- sure on the vessels (admitting there existed any) remov- ed, by means of any aeriform fluid, without the effect of restoring motion to the heart and arteries, provided we apply no oxygen gas at the same time. This last mentioned author (Mr. Coleman) in attempt- ing to refute the position of Dr. Goodwyn, relative to the specific action of red blood on the left auricle and ventri- cle of the heart, adduces as an argument to support his opinion, and refute that of the doctor, the circulation of the blood in fishes, which he says is kept up by the stimu- 42 lus of black blood. To discover the foundation for this apparently false fact, the following experiments were made. Having procured several fish, which were of the same genus, and nearly equal in size, I committed one to dissection, while alive. As soon as the heart was laid open to full view, I could distinctly see its action, which continued for a length of time, with considera- ble force and regularity. The blood was observed to enter the auricle of a colour not quite so florid as that of warm-blooded animals, and which was observed, when circulating through the liver, to resemble, in colour, ve- nous blood. The heart was viewed through a magnify- ing glass, for a length of time, during which the circula- tion of red blood continued without interruption. Ano- ther* was treated in the same way, and with similar re- sults. They both respired frequently during the operation. Thus we may infer, that the same changes, produced on the blood, in circulating through the lungs of quadru- peds and other animals, by respiration, is effected on the blood of these aquatic animals; and certainly for the purpose of effecting the same endf. • A third fish was plunged into a glass vessel filled with, and inverted over "water, in the pneumatic tub, so as to exclude all communication with the ex- ternal air. He was taken out dead in ten hours. A fourth was allowed to swim at liberty in water of the same temperature, contained in a large tub. He remained in this situation for threedays.at the expiration of which time he was taken out perfectly alive, and was plunged under wat«r highly impregnated with fixed air. During the process of sub- mersion, he was not allowed to rise to the surface; he made frequent at- tempts to inspire: he was taken out dead in six hours. Another fish was plunged under spermaceti oil contained in aglass vessel: he was taken out dead in six honrs and thirty minutes. On dissection, they ■ all exhibited the same disoxygenated appearance. f A knowledge of the immediate dependence of animal life upon the con- sumption of this gas (vital air) through the medium of respiration, was fa- :miliar to our ancestors in medicine. " The air is the fewelof vital Jlame without which it would speedily languish and go out." Again, the same au" "thor observes, " Fishes, and other water animals, cannot support life with- 43 Doctor Goodwyn, in his ingenious work, entitled M Connexion of life with respiration," after numerous ex- periments, concludes, that in consequence of obstructed respiration, the blood is deprived of that quality communi- cated to it by the oxygenous part of the atmosphere, in which resides its power of action, on the left side of the heart; the effect of which privation is a defect in its stimulant power, rendering it incompatible to the exciting of action in the left auricle and ventricle. This theory appears, from the result of our experiments, to be the most rational, and on which we will now proceed to make some observations. If the immediate cause of death is a disoxygenation of the blood, depriving it of its red colour (arterial blood) we will expect to find animal life supported under water, in proportion to the quantity of this fluid, assisting in the system, at the time of submersion. To ascertain which the following experiments were made. EXPERIMENT XX. Having procured seven kittens, of the same litter, and nearly equal in size, my friend, Mr. Nelson, holding a atop watch, I exposed two of them to the action of oxygen gas, contained under a glass vessel, inverted over the pneumatic tub, (obtained from the black oxide of manganese by heat) for the space of ten minutes, after which they were both plunged under water, and struggled for six minutes, when they became feeble, and were taken out, apparently dead, in seven minutes and fifty seconds. The third was treated in the same manner, with similar results, varying only in degree; on dissection, the heart was still contracting, and retained its irritability for a very considerable time, in two instances for the space of five hours. The fourth and fifth were plunged under water of the same temperature, in a natural state, and were taken out, appa- out it; for if you put your hand or any covering over a vessel containing fish, so as wholly to exclude the air, they will be suddenly suffocated." Buy on the Wisdom o*God, manifested in the Watts of Creation,page 72. 44 rcntly dead, in three minutes and ten seconds, but, on dissec- tion,the heart was still contracting, though beingfecble, and ceased altogether in a few minutes. To ascertain how far am peculiarity of constitution may have tended to prolong life in these experiments, the re- maining two kittens were plunged into water, in a natural state*, and were both of them taken out dead in three minutes and thirty seconds. Hence we can infer no in- accuracy on that head. Desirous of being very accurate with these experiments, I procured four pups of the same litter, prefering them to young kittens, from their being less tenacious of life, and on that account more analogous to the human species. EXPERIMENT XXI. Having procured four pups, I plunged two of them into an atmosphere of pure oxygenous gas, (tested in the eu- diometer) and confined them in it for the space of ten mi- nutes; at which time they were both submersed, taking care not to permit them to respire atmospheric air, during the process. They both struggled with considerable force for seven minutes, and were taken out apparently dead, the first in eight minutes and thirty seconds; and the other in nine minutes. The irritability of the heart was still consider- able, which continued to contract for several hours after dissection. The remaining two were plunged into water of the same temperature, in a natural state, and were taken out apparent- ly dead in two minutes and forty second*.; and on dissec- tion, the heart was still irritable, but retained if only a short time. We are thus fully convinced, by comparing the result of these experiments, that the considerable difference in the period of death, could not have been influenced by any peculiarity of constitution, or other circumstances, but • By a natural state, I mean that which has not undergone an artificial change. 45 depending on the oxygenation of the animals, which were caused to respire this gas, before they were submersed. Hence we conclude, that animal life is actually supported under water in proportion to the oxygenation of the system at the time of submersion. To ascertain how long an animal could live under water, when permitted to respire, by means of a tube, through which the external air is allowed to have access to the lungs, the following experiment was made. EXPERIMENT XXII. After laying bare the trachea of a large dog, a perforation was made into it, large enough to admit the small end of a long curved tube, about the size of a large goose quill, after some little difficulty the tube was placed in the canal of the wind-pipe, and a strong ligature was immediately applied, including it very firmly in this situation. The large end of the tube now communicating with the exter- nal air, the animal was plunged under water, and confined be- low its surface during the process. In this situation he contin- ued to breathe,apparently withoutmuchdisadvantage(except the considerable irritation excited in the trachea by the tube, which caused him to struggle much) for one hour, his pulse at first was frequent and weak, from the operation of fair, and the sudden change of temperature.; but returned to its natural action before the expiration of the hour. The large end of the tube, communicating with the external air, was now completely filled up with soft wax, cutting off the access of air to the lungs; the animal became immediately affected by^it, struggling with considerable force, and making repeated efforts to inspire, without being able to ef- fect it. He was taken out dead in three minutes and ten seconds, and, on dissection, exhibited the same disoxygenat- ed appearances, as we have related in several of the preced- ing experiments. This experiment was repeated on another dog of the same size, the results were similar. We thus observe, that an animal can live and have his circulation perfect, for the space of one hour under water, 46 (during which time he appeared to labour under very little disadvantage), when he is allowed to respire, in the manner related above, and very probable would live for whole days in this situation—provided food could be conveyed into his stomach. But immediately on obstructing the passage of air to the lungs, death takes place. Hence the propriety of saying, that the water or other fluid in which animals are unfortunately drowned, produces no other effect than that of indirectly cutting off the communication between the lungs and the external air, which is followed, in a few minutes, by a disoxygenation of the blood, the effect of which is either a diminished irritability of the heart, which is still reparable, or an exhaustion which constitues death. We shall now, with a view to discover the relative effects of inspiring at different times, equal portions of pure oxygenous gas, and atmospheric air, make some experi- ments on the human respiration. EXPERIMENT XXIII. Having occasionally, for several days, accustomed myself to suspend my respiration after making inspirations of twenty-five cubic inches of atmospheric air, I was able, after frequent repetition and perseverance, to suspend it to the extent of one minute and ten seconds, beyond which I could not possibly extend it: and to arrive at that was a matter of no small difficulty, for at first I was only able to suspend it for thirty seconds, but, by perseverence, I gra- dually increased the time from thirty to thirty-five, to forty- five, to fifty, and, with the greatest distress, to seventy seconds, at which time I was scarce able to stand, my face purple with a sense of fulness about my head, and consider- able depression across my chest. Having some oxygenous gas at hand, an inspiration of it was taken, when, in a few seconds, the disagreeable symptoms were dispelled. I omitted this disagreeable mode of experimenting for several days, so that the result of the following should not be influenced by habit. 47 EXPERIMENT XXIV. I inspired twenty-five cubic inches of pure oxygenous gas, obtained from the black oxide of manganese by heat. The stimulant effect of this gas was soon perceived, it diffused a pleasurable degree of warmth through my body, and quick- ened my circulation. Having a stop watch before me, I observed I could, with considerable ease, suspend my res- piration for three minutes with this portion of gas, which, on being expired, was received into a glass vessel filled with water, and inverted over the pneumatic tub, a portion of it was now mixed with nitrous air contained in the eudiome- ter, which formed a small portion of nitrous acid vapour, indicating the presence of oxygen gas. It must here be observed, that the air expired in experiment XXIII, after suspending the respiration for seventy seconds, was also tested in the same manner, but not the smallest portion of oxygen gas could be detected, it likewise instantly extinguished a taper when plunged into it. Here we observe, in experiment XXIII, the same effects produced on the human body (differing only in de- gree) from suspending the respiration for the space of only one minute and ten seconds, during which time the portion of oxygen contained in twenty-five cubic inches of common atmospheric air, (which is allowed to be seven,) was en- tirely consumed, and was succeeded by the same symp- toms observed externally to take place during submersion, in which death occurs in from two to three and four minutes. From the experiments of M. De La Metherie,* which are allowed to be very accurate, we are told that an animal consumes, in the space of one hour, three hundred and sixty cubic inches of oxygen gas, (but which consumption, I think, must be in proportion to the size of the animal) this calcula- tion we will apply, however, to the respiration of a stout ro- bust man, who we will suppose in drowning, immediately before he sinks the last time, to make an inspiration of one hundred cubic inches of atmospheric air and allow him to retain this portion until death, which is not the case. * See Chaptal's Chemistry. 4H His system will become completely disoxygcr.atetl in the space of four minutes, forty-one and three fourths of a second, admitting he had taken in with the hundred cubic inches the twenty-eight of oxygen, allowed to be contained in that volume of atmospheric air. Here then we see, that exhaustion of irritability of the heart is, in many instances, immediately subsequent to a disoxygenation of the blood; but the muscular fibres of dif- ferent animals retain it a longer or a shorter time, accord- ingly as they part with it with more facility. We will apply the calculation of Mr. De La Metherie to the respiration of smaller animals. The greater part of the animals, the*subjects of these experiments, would in- spire, immediately before they were plunged under water, a volume of air not less than twenty-five cubic inches. Now, in twenty-five cubic inches of atmospheric air, there is allowed to be seven of oxygen gas, in mixture with eighteen of azotic; and if he consumes three hundred and sixty cubic inches in an hour, we infer, that eleven and one fourth cubic inches is indispensably necessary to support life for the short space of one hundred and twelve and a half seconds, or one minute and fifty-two and a half seconds. Here is at once a deficiency of four and a quarter inches of the given quantity consumed, in the given time of one minute, fifty-two and a half seconds. Hence the animal dies in from two to three minutes, perfectly disoxygenated. From the result of several dissections, after death from hanging, in which appearances were analagous to those which we discover after death from drowning, we cannot but infer the nature of the disease to be the same, and that the extinction of life is effected in the same way. EXPERIMENT XXV. Having laid bare the trachea of a large dog, a perfora- tion was made into it, large enough to admit a canula, about the size of a large goose-quill, which was firmly secured in it by a ligature. He was now set at liberty, ap- 49 pearing not to labour under any other disadvantage, than the degree of irritation excited in the trachea by the tube. At the expiration of thirty minutes, during which time he respired with but little interruption, a noose was applied round his neck, above the puncture, after which he was sus- pended in that situation for one hour. He struggled but very little, continuing to breathe, during the process, through his artificial wind pipe. Another ligature was now applied, below the puncture in the trachea, completely ob- structing the passage of air into the lungs, when he died in three minutes and twenty seconds. EXPERIMENT XX^,* Assisted by my friend Mr. Grimes, the trachea of an- other dog was laid bare, and treated in the same manner; after which a ligature was applied round his neck, above the opening, and on being pulled by two persons, was closed to a considerable degree, more so than if the animal had been suspended or hanged. During the process, he con- tinued to Jbreathe almost as usual, and rose up repeatedly, having a desire to walk. In this situation, he was allowed to remain for one hour, after which a second ligature was passed round his neck, below the opening made in the trachea, when he died in three minutes. The irritability was still perceptible in both of them, but was very feeble, and continued only for a few minutes. Thus we are fully convinced, that an animal may be suspended by the neck, for the space of one hour, without receiving any considerable injury from it, provided he is allowed to respire in the manner related above, during the process; but as soon as the admission of air into the lungs is cut off by ligature, we observe the extinction of life fol- lows, in from three to four minutes, exhibiting, on dissec- • The illustrious Professor Munro, of Edinburgh, made an experiment, similar to the above, with nearly the same results. Vide Munro on the nerves, p. 7, sect. viii. 50 tion, the same disoxygenated appearance of the blood, as that discovered on dissection after death from drowning. We will now turn our attention to another subject of this essay, which is highly interesting, and one which merits more investigation than I have at present time to bestow on it....which is suspended life, from the ac- tion of unrespirable airs on the animal body;....viz. hy- drogenous gas, azotic gas, carbonic acid gas, and lastly, the carbonated hydrogenous gas. EXPERIMENT XXVII. ?Jr. Foissin hnlding a stop watch, I plunged a half grown pup into an atmosphere of inflammable air (con- tained under a large glass vessel, inverted over water, in the preumatic tub, and obtained from the decomposition of water.) In two minutes, he is not much affected, respiring almost as usual; in five, he moves about briskly in the vessel, making a yelping kind of noise, and seeming desir- ous to escape; in seven, respiration laborious, which in- creased rapidly; and in eight, ceased altogether. The animal was taken out apparently dead, in fourteen minutes. On dissection, the heart was discovered to be in motion, but was very weak, and it ceased to move at all in a few minutes. The blood in both sides of the heart was black, and more accumulated in the right than left side. The lungs were found somewhat collapsed, but con- taining a considerable portion of gas, which was tested in the eudiometer, and was discovered to be inflammable air, in mixture with carbonic acid and azotic gases. Another dog, of the same size, was treated in the same manner, with an- other portion of gas, and died in fifteen minutes and ten seconds. On dissection, the irritability of the heart ap- peared to have been perfectly exhausted, by the action of the gas during the process, the blood in both sides of the heart, and all through the body, of a dark colour, indicating a privation of oxygen. 51 TO ASCERTAIN THE COMPARATIVE EFFECTS OF AN ARTIFI- CIAL ATMOSPHERE OF THIS GAS COMBINED WITH OXYGEN GAS, ON THE ANIMAL BODY, WITH THAT PRODUCED BY INFLAMMABLE AIR ALONE, THE FOLLOWING EXPERI- MENTS WERE MADE. EXPERIMENT XXVIII. After mixing with seventy-two parts of hydrogen gas twenty-eight of pure oxygenous (by agitating them together in a large glass vessel, inverted over water), I exposed two pups, about four weeks old, to its action. In eight minutes, they both appeared not to be much affected by it, respiring as usual, but in fifteen minutes scratched the sides of the vessel, as if desirous to escape. In this situa- tion they remained for twenty-five minutes; after this they were taken out. The first was then plunged under water, and was taken out apparently dead in three minutes; but on dissection, the heart was still contracting, and the blood somewhat brighter than it was in the two which were killed in hydrogen alone. The other was set at liberty, and per- fectly recovered in the course of a few hours. Here the effect of oxygen, in supporting life in these animals, is striking. From these results we infer, that life was supported, in the two last experiments, by the oxygen gas, contained in the artificial atmosphere, keeping up the oxygenation of the blood (during the process), which in those that were killed in hydrogen alone, as we have noticed, was black, and the irritability nearly exhausted; while in these it was somewhat florid, the motion in the heart strong, and which continued for a length of time. EXPERIMENT XXIX. Having procured a large quantity of azotic gas, from nitric acid and fresh muscular flesh, two pups were plunged into an atmosphere of it (contained under a glass vessel, inverted over water in the chemical tub). They both struggled severelv, appearing to labour under considerable distress, about the region of the thorax. The first died in eight minutes and ten seconds, the other in ten minutes. yj. On dissection, the lungs were found about half collapsed, and resembling, in many places, an ecchymosis, the blood throughout the body of a dark colour, resembling venous blood, and the irritability of the heart nearly exhausted. The lungs appeared to have laboured under the influence of the nitrous acid vapour, formed by the azote uniting to the small portion of oxygen present in the lungs, at the time the animals were plunged into the azotic gas. These experiments were repeated on several young kittens, with similar results. We shall now proceed to make some experiments on the suspension of vital action from carbonic acid gas; which do not unfrequently prove a source of human misery, being found so plentifully generated in domestic places. EXPERIMENT XXXI. Having procured three pups of the same litter, and about three weeks old, viz. A. B. and C. they were all ex- posed nearly at the same instant (a few seconds intervening) to the action of carbonic acid gas, contained under a spa- cious glass vessel inverted over water in the chemical tub, and procured from powdered marble and sulphuric acid. In ten seconds they are not much affected, respiring with ease; in twenty began to grow uneasy, making efforts to escape; in forty seconds becoming furious, respiration la- borious, and appearing to labour under considerable dis- tress about the region of the thorax, pulsation in the heart now quick and full; in one minute they were all furious, scratching the sides of the vessel with considerable force, in two minutes the difficulty of respiration much increased, pulse nowdiminished in quickness,but not in fulness,becom- ing slow and full. These violent symptoms rapidly increased for three minutes, when they became very feeble and re- laxed. None are now able to inspire, except C. who re- spires occasionally; in four minutes they are all very lan- guid. No efforts are now made to inspire, and all of them except C. who still moves about, though very feebly, ap- pearing to be in a state of torpid insensibility, evincing no sensation on being pinched with the point of a sharp 5$ instrument. A. and B. were taken out dead in four mi- nutes and thirty seconds. On dissection no signs of irrita- bility could be discovered in the heart of A. and B. to which the galvanic influence was applied; but in that of C. there still remained some, though very inconsiderable, which lasted but for a few minutes. The blood in both sides of the heart, the pulmonary artery and veins, was perfectly black, and much accumulated. The lungs were about half collapsed, and of a darker colour than natural. The air contained in them was forced out by pressure and received into separate vessels....From the lungs of A, I procured one and a half cubic inches, from B, one and a quarter, and from C, one and three quarters; after which each portion was tested separately by the eudiometer; but in which I could detect not the least portion of oxygen gas, a portion of it was then sent up through a column of lime- water contained in a glass tube, when a considerable preci- pitation of the carbonate of lime took place. My friend Mr. Walmsey holding a stop-watch, I plunged a large rat into the same portion of gas, which died in three minutes and forty seconds. On dissection the irritability of his heart was still perceptible, but conti- nued for only a few minutes. Other appearances were the same as those related above. The brain in these experiments was observed to be per- fectly natural; no turgescence of its vessels, as has been reported to take place, could be discovered, and, though full of black blood, they were never found in a state of moderate distension. My fellow graduate Mr. Nelson attending to the watch, I plunged two pups of the same size, and about six weeks old, into an atmosphere of concentrated fixed air, contained under a large glass vessel, which I was forced to press down with my left hand, to prevent its upsetting from the pressure of the gas, which was very pure, extinguishing a taper, when poured from one ves- sel into another. The symptoms enumerated in the pre- ceding experiments occurred here to a violent degree, and lasted for three minutes and thirty seconds, after which they became very feeble, and so relaxed that their 54 heads were obliged to be supported above the water, to prevent their drowning, and in four minutes one was taken out dead, the other still shewing signs of life, but died in four minutes and thirty seconds. On dissection nothing like congestion in the vessels of the brain could be dis- covered. The superior longitudinal and lateral sinuses contained black blood but were barely full. The irrita- bility of the heart was not perceptible, though operated on by the stimulus of the galvanic influence. Although contrary to the result of experiments, as seve- ral authors have supposed that apoplexy is produced by the action of this gas, and have stated it as the immediate cause of death, we will put it to a test of experiment. If apoplexy has any share in producing death, as it consists in an accumulation and congestion of blood, in the vessels of the brain, producing extravasation, effusion, &c. &c. the ef- fect of which is compression. We will rationally expect to find the periodof death protracted by diminishing the quantity of blood sent from the heart to the head and brain in a given time, and vice versa, by increasing the accumulation and congestion of blood in the brain, we will certainly expect to facilitate the death of the animal, to ascertain which the following experiments were made EXPERIMENT XXXII. The carotid arteries of two large pups, C. and D. were laid bare and secured by ligature, just after they left the top of the thorax, after which the external wound was closed up, and the animals set at liberty; they appeared to labour under no disadvantage for the space of three hours, at which time they were exposed to the action of carbonic acid gas, contained under separate glass vessels, inverted over water, in ten seconds they are not much af- fected, in twenty some what so, making efforts to escape, in forty respiration laborious, and attended with much dis- tress, pulse quick and full, in one minute they are furious, struggling with considerable force, and difficulty of respir- ing much increased. These violent symptoms increased rapidly for the space of three minutes, when they became vtry feeble, appearing to be in a sound sleep, but moving 55 occasionally; D. still making feeble efforts to inspire, in four minutes and five seconds C was taken out dead, and D in four minutes and twenty-five seconds. On examin- ing the brain, very little blood could be discovered in its vessels. Its sinuses about half full of extremely black blood. No extravasation was found between its coats, nor effusion in its ventricles, the brain appearing perfectly natural. EXPERIMENT XXXIII. Having laid bare the external and internal jugular veins, of two pups, E and F, ligatures were passed round them with a view to prevent as much as possible the return of blood from the head and brain; the external wound was now stitched up, and the animal permitted to run about at large. In thirty minutes E appears somewhat affected, having a disposition to lay down; in forty minutes F ap- pears drowsy, eyes dull and heavy, respiration is continued as usual; they were allowed to remain in this situation for a considerable time, during which evident symptoms of apo- plexy occurred. At the expiration of three hours they were both plunged into an atmosphere of fixed air, contained under separate vessels. The violent symptoms already mentioned in the above experiments, occurred to a consi- derable degree in these, but were not perceptibly aug- mented. E was taken out dead in four minutes and twenty seconds, and F in four minutes and fifty seconds. On dissection the vessels of the brain were found extremely turgid with blood, particularly the sinuses, the vessels of the choroid plexus, considerably distended with black blood, and in the lateral ventricles was found a yellowish coloured fluid. The inferences to be drawn from these experiments are very striking; they prove, in a satisfactory manner, the impropriety of attributing death to apoplexy, admit- ting it did take place. It is a fact which cannot be denied, that persons have laboured, for a length of time, under a considerable degree of compression of the brain, either from external or internal injuries, and have, at length, been perfectly recovered. Now, if a compression of the 56 brain, in such numerous instances, is not adequate to the extinction of life, though allowed to remain for so long a time, I would ask, why should it prove fatal to animals exposed to the action of this gas, in the short space of from three to five minutes? Having, on dissection after death, from the action of this gas, discovered the same disoxygenation of the blood as occurred in those drowned in water; and showing that life was supported under water, in proportion to the quan- tity of this principle present in the body at the time of submersion, we will repeat the same experiments here, and observe the results. After repeated and deliberate attempts were made to form an artificial atmosphere with fixed air and oxygen gas, by mixing them, from long and continued agitation, I found it impracticable: the carbonic acid gas, from its superior gravity, would in a short time fall to the bottom of the vessel. Wishing to avoid any inaccuracy on that head, I relinquished it altogether, and adopted another more certain mode, which was to hyperoxygenate the sys- tem of my animals, and then to expose them to an atmos- phere of fixed air. EXPERIMENT XXXIII. Having procured six pups of the same litter, and about four weeks old, I plunged two of them into an at- mosphere of fixed air. The first was taken out dead (after much struggling) in four minutes, and the second in lour minutes and forty seconds. EXPERIMENT XXXIV. The remaining four pups, viz. A, B, C, and D, were afterwards treated in the following manner, having previ- ously procured a quantity of pure oxygenous gas, from the black oxide of manganese by heat, which v/as contain- ed under separate glass vessels, inverted over water in the pneumatic tub. The pup A was exposed to the action 57 t>f oxygen gas for ten minutes, after which he was plunged into a quantity of fixed air. He was taken out apparently dead in ten minutes and fifty seconds, but on dissection, motion in the heart was very perceptible, and continued for some time. B was exposed to oxygen gas for twenty minutes; he was then placed in fixed air, and was taken out apparently dead in fifteen minutes, but recovered without having any thing done to him. C respired oxy- gen gas for forty minutes, when he was plunged into an atmosphere of fixed air, and was taken out dead in thirty minutes. D was allowed to remain in oxygen gas for one hour, at which time he appeared somewhat feeble, from the action of the gas; he was then plunged into fixed air, and continued to move in it for thirty-five minutes, after which he was taken out apparently dead, but on dis- section, the heart was still found to be in motion, which lasted for some time. The blood, on dissection of these animals, appeared somewhat florid, and thinner than natural. From the above experiments we draw the following conclusions. 1. That from cutting off the communication of atmos- pheric air with the lungs, the blood is deprived of its florid colour, exhibiting the same disoxygenated appear- ance, as that observed on dissection after death from drowning. 2. That black blood is accumulated in the heart: also in the pulmonary artery and veins. 3. That the irritability of the heart and animal fibre, in some instances was so completely exhausted, as notto be perceptible on the application of the strongest ex- citants. 4. But in other cases, motion was still existing in the heart, which was sometimes kept up for a considerable time, by the stimulus of the galvanic influence. 5. That similar to those drowned in water, a torpid insensibility is observed to take place. H 58 6. That no congestion takes place in the vessels of the brain, which appears perfectly natural. 7. That the lungs are not found in a state of perfect collapse, and on testing the air they contained (i. e. the air contained in the lungs of those, which were exposed to the action of unrespirable gasses, without beingpreviously made to respire oxygen gas) not the smallest portion of vital air could be detected. 8. That animals placed in an atmosphere of these gasses do respire, for a longer or shorter time, which pro- cess is performed with considerable more ease in hydro- gen and azotic gasses, than in fixed air. 9. That the calculation of M. de la Metherie, relative to the consumption of vital air in a given time, is appli- cable to the respiration of animals placed in these airs. 10. That it is an absolute fact (which was testified by several gentlemen, present at the time the experiments were made) that irritability and life was supported in an atmosphere of these gasses, in proportion to the oxygen present in the system at the time of experiment. And lastly, That injustice to the test of experiment, we are compelled to acknowledge the modus operandi of these airs, in producing death, to be the same, and that operation to be a positive action on the irritability of the heart and muscular fibres. OF THE HYDROCARBONATE GAS. This carbonated inflammable air is said to be hydro- gen gas holding carbon in solution, and can be obtained in several different ways. I procured it by extinguishing ignited charcoal under water, and receiving the gas as it would rise to the surface. To deprive it of the fixed air it usually contains, it is necessary to agitate in water for some time, when the fixed air will be absorbed, •"The successful application of cold to the body in reeoveringsupv^ed- s *d life from the action of these airs, tends considerably to prove the stimu- lant effect they have upon the irritability of the heart and muscular fibre. 59 EXPERIMENT XXXV. My friend, Mr. Thomas, attending to the watch, I plunged two pups, of three weeks old, into an atmosphere of this gas, contained under a glass vessel. In fifteen seconds, they were much affected, struggled hard, and making a noise similar to those exposed to oxygen gas; in twenty, respiration short, and pulse very quick, and more full than natural; in forty still the same, in one minute they were furious, pulse still quick and full; in one minute and thirty seconds they both became feeble, and more relaxed than I had ever seen them in fixed air, being obliged to support their heads above water, to pre- vent their drowning. In two minutes and thirty seconds the first was taken out apparently dead, and the second in two minutes and ten seconds, and on dissection exhibited the following appearances. The heart was observed to be still in strong motion, and a regular circulation was kept up for eight or nine minutes, which was indicated by di- viding one of the intercostal arteries, when blood as red as scarlet was sent through it with considerable force; the lungs were of a beautiful florid colour, similar to those placed in oxygen gas. The blood throughout the body as red as scarlet, the two venaecavae, the pulmonary arte- ries aad veins, the jugular, the hepatic, and splenic veins, resemble so many chords of a bright red colour. The irritability of the heart continued for a length of timei EXPERIMENT. XXXVL In the presence of Dn Roebuck and Mr. Grimes (the former gentleman attending to the watch), I plunged a pup of eight weeks old into a quantity of this gas. TI: : animal struggled considerably, for one minute and twenty seconds, after which he became very feeble and relaxed, but still respiring occasionally. He was taken out appar- ently dead in two minutes and forty seconds. On disscc* 60 tion the heart was still in motion, and circulation went on for some time with extremely red blood; the liver ap- peared of a dull red, and the spleen of a bright red colour; the brain appeared natural, with its sinuses full of very red blood. EXPERIMENT XXXVII. In order to discover the appearance of the blood of a healthy animal, of the same kind, and nearly about the same age, the following experiment was made. Assisted by Mr. Grimes, we removed the sternum of a pup, while alive, together with the cartilages of the ribs; after which we removed the pericardium, and laid the heart open to full view, which was still in regular and strong mo- tion. The blood was seen passing through the pulmonary veins to the left auricle, of a florid colour, and was observed to be very black when returned from the extremities to the right auricle and ventricle. The animal died in a few minutes from the loss of blood. EXPERIMENT XXXIX. Doctor Rosseau attending to the watch, anotjber pup was exposed to the action of this gas. He struggled vio- lently for several minutes, respiring apparently with much distress; pulse full and frequent, and continued so for four minutes and fifty-five seconds; at which time it be- gan to diminish in force, but not in frequency; the animal appearing to be in a calm sleep, but moved when stimulated to it. He did not die until seven minutes and fifty seconds, after which he was taken out and dissected, with results similar to those already related. Whether this difference in the period of death was in consequence of some peculi- arity of constitution, or owing to the quality of the gas, I cannot say. From observing the similarity of effect produced in the blood of animals, made to respire this gas, to that induced 61 by the action of oxygen gas, I was induced to investigate, still farther, these analagous effects on the animal body to that gas. EXPERIMENT XL. Having procured four pups of the same litter, viz. A, B, C, and D, A was exposed to the action of this gas, con- tained under a glass Vessel, for fifteen seconds,during which time he struggled very hard, respiration quick and short. He was now taken out, and immediately plunged under water, (without being permitted to respire atmospheric air) when he struggled very severely for four minutes and twenty seconds, after which he became feeble, and in five minutes and thirty seconds he ceased to move, and was taken out apparently dead, but on dissection motion was still percep- tible in the heart, and the blood somewhat florid. B was now exposed to its influence for the space of thirty seconds, after which he was immediately plunged under water. He continued to struggle very hard under the water for five minutes and thirty seconds, when he be- came weak, and considerably relaxed, he was taken out dead in six minutes and fifty-five seconds. C and D were now plunged under water of the same temperature, in a natural state, and were confined below its surface. C was taken out dead in two minutes and fifty seconds, and D in three minutes and ten seconds; and, on dissection, the irritability of the heart was barely percepti- ble, and the blood completely disoxygenated. Here the striking effect of this gas on the animal body, with that produced by oxygen, merits, in an eminent de- gree, the investigation of the philosopher. No satisfactory explanation has yet been given of this singular and interest- ing phenomenon. I shall not offer a conjecture on the subject. The fact is so that it increases action in the heart and animal fibre, producing a change in the arterial and venous blood, similar to that induced by oxygen gas. Its modus operandi on the animal body, has been sup- 62 posed by a late celebrated author*", to be sedative, for, after relating an experiment made upon himself, by respiring this gas, proceeds thus " that hydrocarbonate acts as a sedative, i. e. that it produces diminution of vital action, and debility, without previously exciting it." This conclu- sion is not sanctioned by the result of the preceding expe- riments, where we find a very strong action is excited in the heart and arteries for the first sixty or eighty seconds, after the animah have been exposed to its influnce. We cannot doubt the accuracy of Mr. Daty's experiment, but the incorrectness of his conclusion is obvious. From the result of the preceding experiments on suspended life, from drowning, hanging, and the action of unrespirable air, we infer the proximate cause of death to depend upon a disoxygenation of the blood and muscular fibre, in consequence of which a suspension of circulation takes place. Whether the heart and animal fibre, derives its irritability from oxygen, through the medium of oxygenated arterial blood, as some modern medical philosophers have supposed, by reasoning from the result of experiment ?—or Whether it constitutes a powerful congenial or specific stimulus to the heart and muscular fibre, essential to their excitement, and therefore to animation? are questions that demand much and serious reflection, to enable the philosopher and enquirer after truth, to solve satisfactorily. I will leave the candid reader to judge for himself, the shortness of time, together with the limits of an inaugural thesis (which have already been overleaped in this essay), will not permit me to bestow, on this interesting part of science, that attention which it merits, and which I shall be happy to give at a future time. The former hypothesis has been ingeniously defended by Dr. Girtanner, and is certainly founded on numerous and substantial facts, and, vice versa, there are many facts in the medical world that militate against it. Thus then, we conclude, that the accumulation of black blood in the heart, the pulmonary artery and veins, and • Humphrey Davy. Vide Chemical Researches, page 471- 63 other phenomena discovered to us by dissection, respecting the function of the lungs and the circulation of the blood, are nothing more than the effect of a disoxygenation of the blood and muscular fibre. Hence we have demonstrated to us, in a convincing manner, the unbounded utility of the immediate application of this gas* (which may be justly called the magnum dei donum) in our attempts to remove a suspension of vital action from such unfortunate accidents. INDICATIONS OF A TEMPORARY EXHAUSTION OF THE CA- PACITY FOR LIFE WHICH MAY AGAIN BE ROUZED INTO ACTION BY THE APPLICATION OF POWERFUL STIMULI. 1. A degree of heat not much below the natural standard. 2. Feeble contraction and dilatations of the heart, felt externally. . 3. A degree of tremor in the external muscles about the mouth, temples, abdomen, &c. 4. A contraction of the muscles in different parts of the body, on the application of common stimuli. 5. An alternate contraction and dilation of the pupils of the eye on the application of a strong lightf. • Oxygen gas. It can be obtained in very large quantities from several substances at a very reasonable rate. From one pound of the oxide of man- ganese, expased in an earthen retort to a white heat, we procure at the trifling expense of one dollar, apparatus and every thing included ten gallons; would it not be a grand object to the humane societies, to keep always forty or fifty gallons of this air (which can readily be done by corking it up in tight bottles, or very close bags) to have recourse to on cases of emergency, where the loss of a few minutes in the restorative art is so frequently at- tended with such fatal consequences. f I think it proper to observe, in this place, that the irritability of the iris, in every animal that I have killed, appears to be a very good external sign of the existence of the capacity for life. Having paid much attention to this circumstance in every animal I have experimented on for this disserta- tion. It seems to be more influenced by an equal degree of this principle with the heart, than any other external part, and retains it the longest. In all my dissections of animals, which I have made use of in this work, both of those submersed in water and those in the noxious gases, where I found the irrita- bility of the iris weak and almost exhausted, I also found that of the heart very leeble, and vite versa; but I must confess, that these signs are liable to ^ulSfc^K^tyMMitl might n»»»» rp^be depended upon. 64 6. The smallest degree of remaining susceptibility is indicated, by removing the skin, fat, and cellular membrane, and applying to the muscular fibre the stimulus of the gal- vanic influence, when if the parts are not totally exhausted of irritability, some degree of motion will be excited. INDICATIONS OF DEATH, OR A TOTAL EXHAUSTION OF THE CAPACITY FOR LIFE.* 1. A degree of heat, considerably below the tempera- ture compatible with life.f 2. Rigidity of the body and limbs, which become in- flexible. * 3. A change of colour in the face, limbs, &c. from a healthy red to a leaden blue. 4. Great relaxation of the lower jaw, with considerable flacidity of the tongue, which hangs over the corner of the mouth. 5. Livid spots, attended with a cadaverous odour. 6. The eyes somewhat protruded, and the transparent cornea more glossy than natural, attended with dilated • The relaxation of the sphincter anii, related by authors as a certain indication of death, is perfectly fallacious; and, from the result of my expe- riments, I may assert casual. In many of the animals, this relaxation of the part appeared to a great degree.befbre the external signs of life had disappeared; and, on the contrary, there were many instances, in which it did not occur at all. In several animals, in whom it appeared after submersion, and who shewed no external signs of life, on dissection, both sides of the heart con- tinued in motion for some time ; in two instances, for fifty minutes, and that not inconsiderable. In fact, the irritability of both sides of the heart, I have uniformly observed to continue for a length of time ; in one case, for up- wards of five hours, after that of the external muscular flesh, and the intes- tinal canal, had ceased entirely, and could not be made to contract by the galvanic influence. f This does not take place immediately after submersion: as we find the temperature of the blood contained in the heart not to have beeh dimi- nished, and as heat and irritability are not co-equal, it appears to be a very irrational criterion. « 65 pupils, in which no contraction can be observed, on apply- ing the most vivid light. 7. A morbid insensibility to the impression of stimu- lus. 8. A very certain sign of the extinction of life is a cessa- tion of irritability in the muscular fibre, producing no con- traction on the application of the stimulus of the galvanic influence*: but even this criterion is not infallible, for irri- tability may be totally exhausted in the external muscle and may still exist in the heartf, which retains its capacity for life the longest of any part of the animal body. Hence the uncertainty of external signs, to discriminate between life and death. The books of authors on this subject, are replete with criteria to judge of the existence or non-existence of the irritable*principie. It is not necessary, in this place, to take a separate view of the propriety or impropriety of adopting any of these ambiguous signs, when we have the accomplishment of so great an end in view, as that of res- toring suspended life! Our exertions should never be influenced by any of them, but continued with ardour and unremitted attention, for a length of time. It would be more happy for our unfortunate patients, and a source of greater satisfaction to ourselves, were they expunged alto- gether. They are all fallacious, to a certain degree, and ought never to have the smallest influence on the propriety or impropriety of persevering in our attempts to revive the latent spark; for it is an unfortunate fact, that, in conse- quence of an ignorant confidence placed in them, persons, who might have been restored to life, to their friends, and to society, have been consigned to the grave. This is an important subject, and one that has been anxiously investigated by philosophers, to discover a just criterion of judging with more certainty in these cases, • To make use of this as a test, it is indispensibly necessary to remove the integuments, and then to operate upon the bare muscle. t I mean, by the external muscular fibre, those which present them. selves to our view, immediately on removing the skin, fat, and cellular mem- brane, in different parts of the tSody. I 66 whether life is extinct, and our patient a mass of dead matter, or whether, by our perseverance, he may not be again recovered. The most indubitable sign is allowed to be a putrefaction of the body, or disorganization of the fibre. But as this criterion is not only extremely disagree- able, but must be attended, in some seasons of the year, with considerable danger, it is seldom applied. The ap- plication of the newly discovered phenomenon of animal electricity* appears to promise much on this head; for although irritability may exist in the heart, when not indi* cated by its application to the external muscular fibre, we may safely conclude it is so far exhausted, as not to be capable of again taking on the action of life. .', EXPERIMENTS ON THE MODE OF CURE. Having obtained a large quantity of pure oxygen gas* from the oxide of manganese, and erected the chain of tum- blers of volta, to the number of one hundred and fifteen, and containing two hundred and thirty pieces of zinc and copper, from which I procured the galvanic influence very strong, I proceeded to apply them in recovering sus- pended life. EXPERIMENT XLI. A large dog was plunged under water, and confined be- low its surface for six minutes, after which he was taken out apparently dead, which was indicated by the common external signs. Sixty cubic inches of the gas was now thrown into his lungs, by means of a large gum-elastic syringef, to which a flexible tube, with a common clyster pipe at its extremity, was appended. The gas was allowed • The galvanic influence, which derives its name from Hb happy disco- verer, professor Galvani, of the university of Bologna. f For a description of the apparatus, and the various methods fot in- flating the lungs, &c. &c. I refer my readert to the ingenious works of Mr. Kite, Dr. Goodwryn, and others. 67 to remain in the lung9 for twenty or thirty seconds, when it was again forced out by pressure. This artificial res- piration was continued for five minutes, being repeated every thirty seconds; and during the intermission, the gal- vanic influence was applied to the region of the heart, which excited motion throughout every part of the body. The animal soon began to make feeble efforts to inspire, which, in a short time, he could effect with some ease. The artificial respiration was now discontinued, and the shocks from the chain of tumblers continued to be sent through the chest, until the heart had recovered its lost excitement. EXPERIMENT XL. Another dog, smaller in size, was treated in the same manner, when he was taken out in three minutes, with some remaining symptoms of life. The stimulus of the galvanic influence was applied to the region of the heart (having previously removed the hair), which was followed by a considerable degree of agitation throughout the whole body; this was continued for a short time, when the animal began to respire with much ease, and perfectly recovered in a few hours*. Two pups, of four weeks old, were successfully treated in the same manner. EXPERIMENT XLI. A half grown cat was submersed, taken out ap- parently dead in four minutes and fifty seconds. The lungs were immediately inflated with oxygen gas, which was forcibly thrown in by compressing the gum-elastic sy- ringe, and an artificial respiration kept up for several mi- nutes, when he was observed to make a feeble effort to inspire. The galvanic influence was now applied to • In this experiment no artificial respiration was employed ; conceiving it unnecessary from observing the animals to make some feeble inspirations, soon after being taken out of the water, 68 the region of the heart, which immediately excited ft smart contraction; the animal began now to respire, which was still laborious, but soon became easy, and he recovered so as to escape in a few hours. In this animal, the pupil of the eye was observed to contract, though very feebly, on applying a vivid light. EXPERIMENT XLII. Two large spaniel pups were plunged under water, and confined there for seven minutes, at which time they were both taken out, apparently dead. No motion was apparent in the heart to the touch, but the muscular fibres of both of them contracted on applying the galvanic influ- ence. The first was put up to the neck in the warm bath, at the temperature of ninety-eight of Fahrenheit's thermo- meter, which was gradually increased to one hundred and forty. In this medium he was allowed to remain for one hour, without its having produced any salutary effect; irri- tability was still perceptible in the fibres. Friction was now employed, and continued for a considerable time, aided by the injection of vitriolic octher per anum, but without the effect of restoring life. The lungs of the second were immediately inflated with fifty cubic inches of oxygen gas which was again forced out by pressure, and repeated at intervals of fifty seconds. This applica- tion was aided by shocks from the chain of tumblers, which were sent through the chest, with a view of apply- ing it to both sides of the heart. This practice was per- severed in for a considerable time, when the animal began to make feeble efforts to inspire. The shocks were now more frequently applied, and were increased in force, with the effect of exciting obvious motion in the heart. Artificial respiration was now discontinued, the animal respiring with more ease, and in four hours he recovered sufficiently to rise up. He was now placed on a bed of straw, and perfectly recovered in the course of three hours. Another deg was treated in a similar way, and v. kh the same success. 96 EXPERIMENT XLIII. A half grown bull-dog was suspended by the neck for six minutes; at this time he was cut down apparently dead. Irritability was still existing in the muscular fibres, which was produced by the stimulus of the galva- nic influence. He was now laid upon the table, and his lungs inflated with sixty cubic inches of oxygen gas, keeping up an artificial respiration for several minutes, when the animal was observed to make a feeble attempt to inspire. The intercostal muscles were now laid bare, on both sides of the thorax, immediately opposite to the heart, after which a brass wire was curved in the shape of the letter V inverted, so that it should embrace both sides of the thorax at the same time, this was attached to a second conductor, communicating with the galvanic chain after which the shocks were sent immediately through the heart, with the effect of exciting considerable motion, and of increasing the process of respiration.43 This mode of cure was continued for some time, after which it was dis- continued, and the wound closed up by ligature; the ani- mal perfectly recovered in the course of the day. EXPERIMENT XLIV. Two pups, of six weeks old, were exposed to the action of carbonic acid gas for six minutes, at which time they were taken out apparently dead ; their thighs and legs were pricked with a sharp instrument, but appeared to be insen- sible to the impression, the galvanic influence was applied to the bare muscle, when it began to contract instantly. Their lungs were now inflated with oxygen gas, and the stimulus of the galvanic influence applied in the manner re- lated above. This mode of cure was continued for some time, when the animals began to make feeble efforts to in- spire, which they could effect' in a short time with consi- derable ease. This practice was now discontinued, and they both recovered rapidly. Several other experiments £ 70 of this tendency were repeated successfully, which I do not think proper to relate, the results being so similar, and the mode of cure the same ; though it must be observed here, that this practice was not applied in every case with the same happy effect; it failed in one or two instances, not- withstanding it was applied, under the same circumstances, and continued with unremitted exertion for a considerable time. Here, then, the indications of cure* are sufficiently obvious. The result of the above experiments point out to us the rationality of the practice adopted, and demon- strating at once the happiest effects resulting from its imme- diate application. Far is it from my desire to expunge from the list of therapeutics, for suspended life, all of its articles. For although it contains a number of applications, which are not only useless, but prove highly injurious to the animal body in that state, it is by no means destitute of many im- portant articles, but I would even have these viewed in the light of auxiliary applications to those applied in the prac- tice adopted in this essay. This truly important acquisition (the galvanic influence) to the list of applications in the restorative artf is entitled to our serious attention; for although we are induced to believe, from the many striking analogies existing between it and electricity, that it is only a modification of that power, we are convinced, at the same time, that as an application, in those cases, it possesses some peculiar and happy advantages over electricity. The difficulty and trouble of keeping an electrical machine in order: of working it in damp moist weather, the considerable diminution of its • The transfusion of arterial failed in two instances, in the recovery of drowned animals. But I am informed that Dr. Gartley, who intended to write on this subject for his inaugural thesis last spring, made the same ex- periments with success. I think it merits much attention as an application in those cases. f During the course of my experiments I had an opportunity of ap- plying the galvanic influence succ5ssfully in two cases of suspended life, from severe cold, which occurred in two pups of two weeks old. 71 power in moist atmospheres, together with the uncertainty (unless in very skilful hands) of being able to proportion the shocks according to the capacity for life, on a perfect knowledge of which depends its successful application, are disadvantages long since experienced when it was applied under such circumstances. These are disadvantages not connected with the application of the galvanic ifluence. For in the first place, from observation, we find its power some- what increased in the moist weatherf, and not sensibly di- minished in dry and clear weather from its natural standard, and, secondly, there is less trouble, and more economy in keeping it in perfect order, and, thirdly, the shocks can be proportioned to any capacity by only diminishing the number of tumblers. Nothing more is required to obtain it, than to fill up your tumblers or cups with salt and water, and to ar- range them, either in a wooden frame made for the pur- pose, or upon the table, after which each vessel must contain a piece of zinc and copper, about as thick as a dollar, and an inch and a half square, these are to be connected together by brass wire. For the sum of forty dollars, in this way, we may procure one sufficiently powerful to kill small animals; as our object in these cases is economy, we should use those metals, which are the cheapest, and which have nearly the same power—zinc and silver—zinc and gold, &c. &c. have been used, but without much increasing the strength of the influence. With this, then, illustrious professors ! I close my inau- gural essay, which, however imperfect, has been a work of much labour. It is unnecessary to add, that the time allotted to me for the completion of my task has been very short. The subject which I have chosen is, unquestionably, one of the first importance. However unworthy my efforts may be of your protection, from the criticisms of the illi- beral, I have the satisfaction of assuring you and the pub- lic, I have made my experiments, and drawn my conclu- sions, unbiassed by any preconceived ideas on the subject. f This accords with an observation made by Dr. Woodhouse,duringhis lectures en this subject 72 In taking my leave of you, permit me to express my sincerest wishes, that you may enjoy, through the remain- der of your lives, an uninterrupted scene of health and hap- piness. To all of you I am essentially indebted, not only for the invaluable instruction I have received from your lectures, but also for your polite and friendly attention. THE END. Me<£. Hist. wz <¥ m-