stance which swims on the surface of soups, after they have been allowed to cool. When examined by the microscope it has the aspect of a gelatinous mass without determinate form; sometimes cubical shaped crystals are discovered on it, but this appearance is only observed when it has stood for a long time, and are to be regarded as foreign to it. The kisteine remains on the surface for several days; the urine then becomes turbid, and small opaque masses become detached from the kisteine, and fall to the bottom of the fluid; and the pellicle soon becomes destroyed.

The essential character of the urine of pregnancy, then, is the presence of kisteine; and the characters of the pellicle are so peculiar that it is impossible to mistake it for any thing else. A pellicle sometimes forms on the surface of the urine of patients labouring under phthisis, abscess, or catarrh of the bladder, but may easily be distinguished by this circumstance, that it does not form in such a short time as the kisteine, and that, in place of disappearing, as this last, in a few days, it increases in thickness, and at last is converted into a mass of mouldiness. There exists, likewise, a very marked difference between its mucous aspect and that of kisteine-a difference which it is difficult to describe, but which is easily recognised.

Kisteine appears to exist in the urine from the first month of pregnancy till delivery. M. Rousseau has even recognised it in the urine of a few gravid animals.

University of Virginia. Dr. Howard.-Dr. Howard-formerly Professor of Obstetrics in the University of Maryland-has been appointed to the Chair of Medicine in the University of Virginia, vacated by the resignation of Dr. Griffith.

BOOKS RECEIVED.

From Professor T. R. Beck (the author.)-Tables of the residence &c. of Medical Students in the different Medical Colleges, for a series of years. From Professor Gibson (the author.)-Sketches of prominent Surgeons of London and Paris, introductory to a course of Surgical lectures, by William Gibson, M. D., Professor of Surgery in the University of Pennsylvania, Senior Surgeon and Clinical Lecturer to the Philadelphia Hospital, &c. &c. delivered November, 1839, 8vo. pp. 17. Philad., 1839.

From Professor T. D. Mitchell (the author.)—The Pains and Pleasures of a Medical Life: being an introductory to a course of Lectures on Materia Medica and Therapeutics. Session 1839-40. 8vo. pp. 24, Lexington, 1839. From the Committee of Publication.—A Lecture introductory to the course of Surgery, in the Jefferson Medical College, of Philadelphia, for the Session of 1839-40. By Joseph Pancoast, M. D., Professor of the Institutes and Practice of Surgery, &c. &c. Svo. pp. 16. Philad., 1839.

From the same.-Introductory lecture to the course of Institutes of Medicine and Materia Mediça in Jefferson Medical College, of Philadelphia, for the Session of 1839-40. By Professor Dunglison. 8vo. pp. 20. Philad.,

1839.

A report on the history and causes of the Strangers' or Yellow Fever of Charleston; read before the Board of Health. By Thomas Y. Simons, M. D., Chairman of the Board. 8vo. pp. 24. Charleston, 1839.

THE

AMERICAN MEDICAL INTELLIGENCER.

Vol. III.

December 16, 1839.

No. 18.

ART. I.-REPORT OF EXPERIMENTS ON THE ACTION OF
THE HEART, &c.

BY C. W. PENNOCK, M. D., AND E. M. MOORE, M. D.
(Continued from page 269.)

Experiment 9th.-Experiencing great difficulty in analysing some of the movements and sounds of the heart in animals of the size upon which we had experimented, we resolved to inspect the heart of a horse, in which the pulse in health ranges from thirty to forty per minute. In this experiment we were assisted by Drs. Gerhard, Stewardson, Peace, Hardy, Fell, and Goddard, but to the latter gentleman especially we owe our thanks for the assistance rendered.

We found in the animal we had selected that the pulse was about thirtysix per minute, and respiration twenty-eight in the same time.

In order to prolong life, the trachea was opened before the blow was given. Immediately after the blow was struck, which was directed to the forehead, that the skull might be depressed upon the anterior lobes of the brain, the bellows-tube was introduced, and artificial respiration commenced. The skin was dissected back from the median line upon the thorax, the cartilages of the ribs sawn through upon the left side of the sternum, and several of the ribs cut off about one third of their whole length from their sternal extremity. On account of the hemorrhage, we were obliged to secure many arteries, and twenty-five minutes had elapsed from the time the blow was given until the heart was exposed. It presented the left ventricle, the appendix of the left auricle, and a portion of the right ventricle. The pulsations were one hundred per minute, but on account of its size we were enabled to observe the relative contraction of the auricle and ventricle, which we found to succeed each other as follows:-During the contraction of the ventricle the auricle dilates; at the expiration of the systole, the auricle contracts, and the diastole of the ventricle commences, the auricular contraction apparently occupying about one half the time of the ventricular diastole. During its systole, the left ventricle flattens and elongates. During its diastole it shortens, and assumes a rounded form. The sounds were detected, but not loud; the second not existing over the pulmonary artery, but heard over the body of the left ventricle.

Death arrested the further progress of the experiment, twenty minutes after the chest was opened. Dr. Moore coincides with the other gentlemen in reference to the relative contraction of the auricle and ventricle, and thinks his observation, in experiment 1st, erroneous.

Although every experiment had confirmed our views of the agency of the valves of the aorta in the production of the second sound, we had heretofore failed in elevating them; we were also still doubtful respecting the relative

contraction of the auricle and ventricle, for, although the last experiment had appeared more satisfactory on this point than several of the preceding, yet, as life continued but a short time after opening the thorax, and as many circumstances unfavourable to clear and calm observation were connected with the experiment, we resolved to pursue the investigation of these obscure points, and to exhibit the facts that we had observed to a few medical friends.

Experiment 10th-Present Drs. Gerhard, Goddard, Stewardson, Peace, Hardy, Pennock, and Moore. A ram, about six months old. Pulse, 96. Deprived of sensation by a blow upon the head, and opened as in experiment 1st. The heart contracted well, but exhibited great irritability when touched. Its pulsations rose to one hundred and fifty per minute, rendering it difficult to analyse the sounds; but the first sound and impulse was observed to coincide. The spiral motion and elongation were as heretofore detailed. While still contracting forcibly, the heart was removed from the body, and the first sound heard when entire, and also when both ventricles were cut open and emptied of blood.

Experiment 11th.-As the last experiment had not been very satisfactory, the same gentlemen being present, we pursued the investigation upon a calf, four weeks old. Pulse, 105. Both sounds distinctly heard through the chest. Struck upon the anterior portion of the cranium, and opened as before. The pericardium was left entire, to avoid the irritation of immediate contact with the heart. The stethoscope was placed alternately upon the aorta, the body of the right ventricle, and upon the septum, near the apex. Upon the aorta the second sound was found to predominate; upon the body of the right ventricle it was scarcely heard, and the first was present; and near the apex upon left ventricle, or septum, both were detected; the first, louder. The spiral motion, the elongation, and elevation of the apex as before observed. A hook was passed into the aorta by Dr. Moore, and one of the semilunar valves elevated; the eyes of the auscultator were closed, to prevent the possibility of bias from preconceived opinions. While in this position, the auscultator announced the absence of the second sound, and the accession of a rough bellows sound in the first sound. The hook was then withdrawn, and the second sound was declared to have returned. This experiment was tried twice by each, and by some three times in succession, and the results were uniform. No hook was passed into the pulmonary artery, inasmuch as no sound was heard over it at this time. The auricle contracted while in the hand, emptied of blood. Experiment 12th.-A ram, six months old. Present Drs. Stillé, Hardy, Pennock, and Moore. Pulse, 96; respiration, 56. Animal struck upon forehead, as in the previous experiments, and artificial respiration established in three-fourths of a minute. During the opening of the chest much hemorrhage took place. The heart was at first tumultuous in its action, but became regular in a few minutes. The first and second sound were heard over the body of the right ventricle, but more feebly than over the left; both sounds were heard over the left ventricle and aorta, but the second louder than the first over the latter than over the former. Hooks were passed into the ventricle, for the purpose of keeping open the auriculo-ventricular valves. (These, however, failed of effecting the object, as seen upon examination afterwards.) The sounds gradually became more feeble as the heart congested, and the second sound ceased altogether, both over the heart and arteries, while the first still remained. The auricle was observed to contract over its entire surface, as much upon the body as upon the appendix. The contractions with reference to the ventricles were irregular at this time, except for a very short period, when they appeared to precede those of the ventricle immediately, recurring at the termination of repose. The heart contracted one hour after the blow was given.

Experiment 13th.-Wether, nine months old. This experiment failed on account of defect in the apparatus for maintaining respiration. As the

heart became more feeble, the auricle appeared to contract immediately antecedent to the systole of the ventricle, but owing to the circumstances attendant upon this experiment, we feel very uncertain as regards the observation.

Experiment 14th.-Ewe, nine months old. Struck as before. Trachea opened in half a minute. Chest opened in four minutes. Heart tumultuous. It gradually became more quiet, until it fell to 120, and contracted forcibly. The first sound alone was heard over the right ventricle and pulmonary artery. Pressure upon this artery produced a bellows sound in the first sound. The auricles were pushed into the auriculo-ventricular openings by the fingers. The first sound was thus rendered much more feeble, and lost its sharp character; the ventricles contracting imperfectly and irregularly.

Experiment 15th.-A calf, five days old; pulse, 126; respiration, 30. Sensation destroyed by a blow upon the head, as before. Artificial respiration established in two minutes and a half. The heart was exposed in six minutes, rather hurried in its action, but soon fell to one hundred and twenty pulsations per minute. The heart contracted with moderate force. The second sound extremely feeble over the body of the right ventricle and pulmonary artery; but it soon disappeared over both. The sound was still heard over the left ventricle and aorta, louder over the latter. The auricle contracted with a quick motion, the contraction not being confined to the appendix, but extending over the whole body of the organ. As the heart became weaker, the pulsations were slower, and we were enabled to analyse the relative contractions of the auricle and ventricle much better than at any previous experiment. They evidently bore a different relation from what we had previously supposed. The succession is as follows:-First the auricle contracts and the action is immediately propagated to the ventricle, which contracts, instantly, accompanied with the diastole of the auricle; the diastole of the ventricle immediately follows, accompanied with a subsidence of the auricle by passive and not active contraction, which partially fills the ventricle; then follows the state of repose, at the termination of which, the auricle contracts. During the dilatation of the auricle, the vena cava also dilates, but it was difficult to say, whether the cava dilated during the contraction of the auricle or not, as the contraction of the latter was so rapid and so soon followed by the contraction of the ventricle. While still contracting, and when scarcely any sound was heard upon the ventricles, the stethoscope was applied to each auricle, and a sound similar to the first was heard, but very short, and more flapping, resembling very nearly the first sound of the foetal heart.

Experiment 16th.-A calf, two months old. Pulse, 90. Deprived of sensation as before. The chest was opened in eight minutes, and a few ribs removed from the left side. The heart pulsated slowly, and at a rate of 95 per minute; both sounds were distinct, but not loud. The second sound was heard more loudly over the pulmonary artery than on the right ventricle, the sound being but feeble in either position. Both sounds were heard upon the left ventricle. An instrument was introduced into the left ventricle, through the auricle, and the mitral valves prevented from collapsing; this produced congestion of the ventricle immediately, and the action became hurried and irregular. The stethoscope being applied to the left ventricle, the sound was not as loud and clear as before, but not modified in any other manner. The instrument was then withdrawn, and the sound became louder. The relative contractions of the auricles and ventricles were as in the last experiment.

The difference in the intensity of the first sound in this experiment, when the mitral valve was kept open and when allowed to close, may be attributed to the fact that there was no fixed point for the muscle of the ventricle to act upon, by the retention of the blood, and it therefore could not empty itself of its contents, and, of course, would not yield a strong sound.

From the preceding experiments we draw the following conclusions:1st. The impulse is synchronous with, and caused by, the ventricular contraction, and when felt externally, arises from the striking of the apex of the heart against the thorax.

2d. The expulsion of the blood from the ventricles is effected by an approximation of the sides of the heart only, and not by a contraction of the apex towards the base; during the systole the heart performs a spiral movement, and becomes elongated. (Experiments 6th, 10th, and 11th.)

3d. The ventricle contracts and the auricle dilates at the same time, occupying about one half of the whole time required for contraction, diastole, and repose. Immediately at the termination of the systole of the ventricle, its diastole succeeds, occupying about one fourth of the whole time, synchronous with which the auricle diminishes, by emptying a portion of its blood in the ventricle, unaccompanied with muscular contraction. The remaining fourth is devoted to the repose of the ventricles, near the termination of which the auricle contracts actively, with a short, quick motion, thus distending the ventricles with an additional quantity of blood; this motion is propagated immediately to the ventricles, and their systole takes place, rendering their contractions almost continuous. (Experiments 15 and 16.) 4th. From the termination of their diastole to the commencement of their systole, the ventricles are in a state of perfect repose, their cavities remaining full, but not distended, while those of the auricles are partially so, dur ing the whole time.

5th. The sounds are produced by the motions of the heart or its contents, and not by striking against the thorax, as proved in all the experiments; being much louder when the stethoscope was applied directly to the heart, than when to the chest, or with the lungs interposed.

6th. The sounds are more distinct when the muscle is thin, and contracts quickly. Hence the clear, flapping character of the first sound over the right ventricle, as compared with the left.

7th. The first sound, the impulse, and the ventricular systole are synchronous. This sound may be a combination of that caused by the contraction of the auricles, the flapping of the auriculo-ventricular valves, the rush of blood from the ventricles, and the sound of muscular contraction. From experiments 3d, 4th, 6th, and 10th, when the heart was removed from the body, the ventricles cut open and emptied of their contents, the auriculoventricular valves elevated, and a sound, resembling the first, still heard, it may be chiefly attributed to the muscular contraction. That these valves aid but slightly in its production, may also be inferred from experiment 16. 8th. The second sound is caused exclusively by the closure of the semilunar valves from the reaction of the arterial columns of blood upon them, in its tendency to regurgitate through the aortic and pulmonary orifices. This is proved by the greater intensity of this sound over the aorta than elsewhere, the blood having a strong tendency to return through the valvular opening; by the greater feebleness of the sound over the pulmonary artery, which is short, and soon distributes its blood through the lungs, thus producing but slight impulse upon the valves in the attempt to regurgitate; by the disappearance of the sound, when the heart becomes congested and contracts feebly; and, finally, on account of its entire extinction when the valve of the aorta was elevated.

9th. The second sound is synchronous with the diastole of the ventricle.

From these experiments, it will be seen that our conclusions coincide very nearly with those of the British physiologists, the correctness of whose results, when compared with those of the French, may be mainly attributed to the use of larger animals. From our observations, calves, of from four to eight weeks old, are decidedly preferable to other quadrupeds for these investigations. The tenacity of life of calves of this age is greater than in older animals, whilst the cardiac pulsations are slower, and more