protracted dying the fibrin is thus separated, certain modified conditions of blood may obtain, and may favour the tendency to separation. It has long since been shown, that in scurvy the fibrin may separate spontaneously, and in the venesection of scurvy patients, the blood stream has been observed of a white and a dark shade; hence it is possible that the blood in this as in other disorders where disorganisation has occurred, may divide into its parts coincident with the languid motion, rather than as the sequence of such languor. But, that slow motion of blood is of itself favourable to the deposition of fibrin, is fully indicated in the case of aneurism; since there can be no reasonable doubt that the depositions of fibrin layer upon layer, which occur in the aneurismal sac, are greatly influenced by the slowness with which the blood circulates through the dilated part.]

It seems, in truth, that whenever and wherever there is an unnatural dilatation of the circulatory system, there there is obstruction, and there the deposition of fibrin is under favouring circumstances imminent. In the case of a child who died under my care with physical evidence of extensive dilatation of the left side of the heart, the symptoms immediately preceding death indicated to my mind clearly, that the cause of the failure of the circulation arose almost exclusively from the fibrinous separation. There were obstructed circulation, pulmonic congestion, and ultimately a sudden syncope. The post mortem examination proved the correctness of the diagnosis: the endocardial surface of the left ventricle was inlaid with fibrin, deposited in three layers or strata; while the cavity itself contained a rounded concretion, attached firmly to the tendinous

cords of the mitral valve. This concretion weighed seventy-five grains.

In this instance, there were no preceding symptoms indicating hyperinosis, or of any such modification in the character of the blood, as would lead to deposition, nor was the remaining blood unnatural in character.

In describing the formation of hollow cylinders of fibrin, page 68, an illustration was given from a case in which such a hollow cylinder was found in the dilated and roughened aorta of an aged woman. This case affords another example of the tendency of fibrin to deposit in parts of the circulatory apparatus, where an impediment lies in the way of the blood current.

[Thus there have been sketched out samples of the three conditions in which fibrin may be deposited directly from the living blood. In the first and second of these conditions, there is excess of fibrin, and the heart, to use a common phrase, churns out of the blood the concretion. In the third variety, the deposition is passive in character. These conditions may of course occur together.

The concretions of fibrin, to which I have here directed attention, must be considered as distinct deposits from the blood, and are not to be confounded with those small bead-like formations which occur in endocardial inflammation, and are supposed by some pathologists to be exudation products. I am in no position to deny the idea of fibrinous exudation on the endocardial surface; but the matter thus thrown out, if it is ever thrown out, must be limited, and can never build up a large concretion. At the same time, it is possible that such an exudation, in a disease of the acute inflam

matory type, may form a favourable basis for a larger concretion deposited out of the blood.

There have been, indeed, certain instances recorded, in which a fibrinous mass has been found in the heart, having a direct connexion with that organ by bloodvessels, and having an organised character. It is fair to assume that, if such connexion may exist, the union might be accounted for on the principle here supplied. One of the best histories of an organised fibrinous mass in the heart, with which I am familiar, is given by Mr. James Stewart in the Edinburgh Medical and Surgical Journal for April 1817. Here the right and left ventricles contained each a concretion, attached by several peduncles to the heart wall. This concretion when cut into was found exceedingly vascular. Mr. Stewart's case was related with every evidence of care and of truth, and other pathological observers have reported similar observations. Still the evidence has been doubted. I have, however, myself met with one positive proof of the possibility of such organisation. An old lady, a patient of my friend Mr. Beresford, of Narborough near Leicester, died suddenly. On opening the body, the heart was found softened in structure, flabby, and collapsed. In the left ventricle, suspended from between the segments of the mitral valve by a fine peduncle, was a large pear-shaped white body, which moved easily by its neck. The entire heart was brought away by my friend Mr. Thomas Taylor, who was present at the post mortem examination, and who gave the heart to me. The growth in question was unmistakeably, for I examined it minutely, fibrinous. It was connected with the heart at its peduncular part by vessel, and, throughout its structure, vessels

could be distinctly traced. The diagram beneath gives a fair idea of the size, shape, and position of this concretion.

Fig. 7.

The heart, with the left ventricle exposed to view.

A. Aortic valves laid open and reflected back. B. Part of mitral valve.

c. Concretion.

A few years ago, my friend Dr. Sayer kindly showed me a concretion which he had once removed from the right ventricle. The symptoms indicative of the presence of concretion had been present many months, and the base of the mass was so firmly attached to the heart wall, that it was torn away on removal. I examined the specimen carefully, and exhibited it at the Medical Society, but could not ascertain whether it had been organised. I was rather inclined to think not, and to believe that the adhesion had been mechanical only. In truth, so firm are the mechanical adhesions

of this kind in certain cases, that the fact of adhesion must never be accepted alone as a sign of connexion by organisation.]

III. THE BLOOD AS A LOOSE CLOT-SEMI-COAGULATED.

The cases in which the blood is found semi-coagulated, as though its contractile force were lost, and where there is little or no tendency to a separation of fibrin, occur, in the first place, in instances where death has taken place from a lingering arrest of the process of respiration. In forty experiments in which I destroyed life in the inferior animals (dogs and cats chiefly), by making them slowly inhale some narcotic vapour, this condition of blood was usually met with. The results, however, were slightly different, according to the period after death at which the autopsy took place. In instances where the body was opened within two hours after death, I found in several cases that the blood still remained fluid, this state being most marked in cases where the process of death had been most prolonged. In each of these latter cases, the blood commenced to coagulate soon after its removal from the body; and whenever more than two hours was allowed to elapse before the performance of the autopsy, the coagulating process had always commenced.

I found, also, that the character of the gas inhaled made less difference, as regarded the state of the blood, than the mode of administration. If life were cut short in a few seconds by the inhalation of a large dose of the vapour of prussic acid, the process of coagulation, even if the blood were found fluid, was rarely delayed beyond eight or ten minutes after exposure. If, on the other hand, the gas was largely diluted and inhaled