was merely a small fleshy portion about the width, and half the length of the little finger.

The bile contained in the gall-bladder was of rather a pale straw colour.

The stomach contained large pieces of coagulated blood, with a considerable quantity of a coffee coloured fluid. Its inner surface was very much discoloured, more especially about the hole before alluded to. At this part, as well as in the other places, it had a dusky red aspect.

The small intestines were chiefly lying in the pelvis, and were contracted in their diameters.

On opening the thoracic cavity and separating the sternum from its clavicular attachments, a mass of coagulated blood was exposed to view. Upon feeling the inner surface of the first bone of the sternum, it was discovered that it had been rendered rough. It was conjectured that this roughness had been occasioned by pressure from an aneurism formed upon the arch of the aorta. Further search confirmed the conjecture.

The coagulated blood was carefully removed and the sac exposed. Its coats were very thin, and the layers of coagulable lymph which were deposited on its sides, adhered very slightly to each other. Within the sac there was likewise found a ball of coagulable lymph. It was of the size and consistence of the yolk of a hen's egg; in colour it resembled albumen.

Upon the under and anterior part of the sac, two tendinous bands were stretched and inserted into the upper part of the arch of the aorta. They resembled chordæ tendineæ but were destitute of muscular fibres. The under part of the sac was resting upon the bronchiæ. The trachea was full of blood. The aneurismal sac was somewhat larger than a Turkey's egg. The arch of the aorta had undergone an enormous distention, its diameter was greater than that of the sac. Between its

coats there were large flakes of ossifit matter, some of them nearly half an inch in diameter.

The pulmonary artery did not appear to have undergone any change. The pericardium contained about three ounces of serum. The heart itself was not unu. sually large, but very fat. Its cavities were not opened.

The right lung was perfectly healthy, and free from adhesions with the costal portion of the pleura. It was beautifully streaked with depositions of carbon.

The structure of the left lung seemed to have undergone some alteration; it was disproportionately smaller than the right, and adhered very closely at its root to the dorsal vertebræ. The pleura was much thickened, and broke down easily. There was scarcely any fluid in the cavity of the chest.

Many of the bronchial glands were very large; and loaded with the same black deposit, which had so beautifully marked the lungs.

Observations.

The subjects of aneurisms will, for the most part, be found to be intemperate or irregular in their habits, and I am inclined to suspect that they are produced more frequently by the excessive use of spirituous liquors than any other cause.*

Diseased or increased action cannot exist for any length of time, without inducing an alteration in the healthy structure of parts. It is scarcely possible that the heart and arterial system can be stimulated into excessive action, by the repeated use of large quantities of spirit without exciting at least a disposition to disease.

Perhaps the frequent introduction of alcohol into the system impairs the structure of the coats of the arteries.

*Gout is frequently produced by excessive indulgence in spirituous liquors. Are gouty concretions, and the depositions of ossific matter within the coats of arteries constituted of the same materials?

Its pernicious influence upon the stomach, liver, &c. is now generally admitted.

When speaking of the appearances of the lungs and bronchial glands, I stated that they were loaded with what seemed to be carbonaceous matter. Dr. Bostock has ascertained by direct experiment, that this matter is carbon, but I do not think he has accounted very satisfactorily for the manner in which it is deposited. He conceives that it is taken up from the surface of the air vessels by the absorbents, and carried to these parts. He seems either to have forgotten, or not to be aware of the incapability of these vessels to take up carbon. Carbon, or any other body which will not undergo solution in the animal fluids, cannot be acted upon by the absorbent vessels, but will remain unchanged for many years; even from infancy to old age. Marks inflicted by tatooing, &c. can never be removed but by the entire destruction of the parts in which they are situated. It seems to me much more reasonable to suppose, that these particles of carbon are the product of arterial action. The vessels distributed to the glands and surface of the lungs, convert a portion of the blood which is sent to them into carbon. By a similar process it is that the pulmonary artery decarbonizes the blood.

When an unusual disposition of the abdominal viscera is met with, it is extremely difficult to convey by verbal description only, a distinct idea of their relative situation. I trust, however, that I have rendered myself intelligible.

This is the only case in which I have heard of the liver in the human subject, being constituted of only one lobe. This peculiarity might, perhaps, prove indirectly one of the exciting causes of aneurism in this case; for the blood not having so large a space to be distribited through, would be returned from the intestines to the heart sooner than it is under ordinary circumstances;

by which, accumulation, consequent distention, and increase of muscular force in that organ would be produced. Of this I shall, however, speak more at large when I offer some conjectures relative to the functions of the liver.

CHAPTER VII.

The Functions of the Pulmonary Artery.

THAT blood is formed from chyle is universally admitted, but as to the peculiar mode in which the change is effected, or by what organ, has hitherto been imperfectly explained.

It may appear presumptuous in me to attempt at an explanation of a subject of such difficult solution, a subject which the researches and experiments of the most distinguished physiologists have been found insufficient to elucidate. Its immense importance, with the unsatisfactory manner in which it has been hitherto accounted for will I hope plead my excuse.

I am of opinion that the power of converting chyle into blood is resident in the pulmonary artery.

The chyle, conveyed by the thoracic duct to the angle formed by the union of the jugular and subclavian veins, passes with the refluent blood almost immediately into the pulmonary artery: it returns by the pulmonary veins, not in the state of chyle, but in the form of pure arterial blood. By what agent can such a change be effected? The answer must be by means of an artery; for a change in the sensible properties of the fluids of the body can be effected only through the medium of an artery. The mere admixture of chyle with refluent blood cannot possibly convert it into blood, neither can it be effected by the muscular action of the right side of the heart. As therefore no instrument exists by which a

conversion of chyle into blood can be accomplished previously to its reaching the pulmonary artery, and as it issues from the minute branches of that vessel in the form of pure arterial blood, it is self-evident that it must have been converted into blood by the peculiar action of that vessel. How this circumstance could have been so long overlooked appears extraordinary; perhaps the oversight was occasioned by physiologists having assigned to the pulmonary artery, the exclusive property of oxygenating or decarbonizing the blood. The aorta, with its branches, performs many functions; can any physiological reason be assigned why the pulmonary artery with its branches should not perform three or four? or why that vessel should not be as capable of converting chyle into blood, as the spermatic arteries are of converting blood into semen ?

It has been often said that the whitish fluid which is sometimes seen floating in the serum of blood, is chyle; I must confess myself of an opposite opinion. My reasons for thinking otherwise, are the following.

If it were chyle, we should uniformly meet with it an hour or two after food had been taken, or probably in a much shorter space of time; the reverse however happens.

We sometimes meet with the appearance which has been attributed to the presence of chyle after an animal has been deprived of sustenance for many hours.

If it were chyle we should as frequently meet with turbid serum in arterial as in venous blood, and in arterial blood, it would first be seen; this however is far from being the case. I do not recollect ever to have seen it in arterial blood more than six times. In these cases the appearance was probably depending upon some other cause; a cause to which I shall presently advert.

The chyle of geese is perfectly transparent; whereas