nevertheless laid down as a canon, Ob solam crustam inflammatoriam venæsectio repetenda non est.' (Quarin Met. med, Inflam. p. 70.)" Vol. 109, p. 104.

SERIES III.-ON THE CONDITION OF THE FIBRINE OF THE BLOOD IN INFLAMMATION.

A question touched upon in the last extract quoted is treated more at length in the present series of observations:

"The fibrine of the blood exists in a perfectly fluid state in the blood while within the vessels of a living animal, and for some time after being drawn from these. This fluidity, however, is not like an ordinary solution of a solid body in a liquid menstruum. It is true that the alkaline salts hold the fibrine a long time dissolved, out of the vessels, and will re-dissolve it if already coagulated; carbonic acid, too, retards the coagulation to such an extent that it also may be termed a solvent of the fibrine; but the fundamental reason why fibrine is in a fluid state within the vessels of a living animal, and why out of these it more or less readily consolidates, is entirely independent of the alcalescence of the serum and the impregnation with carbonic acid. It is intimately connected with the peculiar vital formation of the tissues, among which a few minutes before it had been circulating. Negative electricity seems also to retard coagulation, but it is not yet clearly made out whether the influence it exerts is purely dynamic, or whether this does not rather arise from the chemical changes induced in the solutions of the salts which are found in the serum in contact with the fibrine. The fluidity of the fibrine in the blood is a species of vital fluidity, and its coagulation is a cessation of this vital property. Although chemists may demonstrate fibrine and albumen to have the same atomic composition, out of the animal body, and from their isomeric characters, may assume each substance will be similarly effected even within the body by chemical influences-and thus simplify the chemical history of those two substances-they will not by that have removed the necessity of their physiological distinction. When we see them in the laboratory we may allow that they are the same organic material the fundamental composition of which is termed by the moderns protein, and it is a matter of indifference whether the same name be given to the two or not: but when we observe them in the living animal, or just extracted from its vessels and yet endued with vital characters, we then see the necessity of distinguishing them by distinctive appellations. One of these materials (the albumen) remains permanently fluid even when out of the vessels, after the coagulation and even the destruction of the clot; the other (the fibrine) more or less readily loses its fluidity and solidifies. Such a difference is amply sufficient to prove the necessity of not confounding together these two organic materials whatever may be the identity of the remote principles which analysis discovers in them. The names fibrine and albumen then, should be preserved at least by physicians, as signs expressive of the two physiological characters peculiar to the mode of existence of this organic material during its functions in the vital circle; while when they are divested of the characters they owe to vitality their radical composition will be most conveniently expressed by the chemists by the term protein."-Vol. 113, p. 333.

Inflammation may modify the fibrine of the blood in three ways: by increasing its quantity; retarding its coagulation; and by rarefying it.

1. Increase in the Quantity of Fibrine.-The author's investigations by means of the areometer confirm the conclusions arrived at by Andral, Becquerel, and others, that in inflammation there is a marked increase of

1847] Condition of Fibrine of the Blood in Inflammation. 315

fibrine; and he believes that from the researches of Becquerel, Rodier, and Mulder, it may be deduced," that this increase of fibrine is due to the oxidation of a proportionate quantity of the albumen of the serum of the blood."

2. Delay in the Coagulation of the Fibrine (Bradifibrina).—Healthy fibrine ordinarily coagulates in a few minutes after the blood has been drawn. If the individual furnishing it is very enfeebled, aged, or very young, oppressed with plethora or overcome by faintness, the coagulation takes place so rapidly as even to occur around the aperture of the vein whence it flows. On the contrary, when the person is suffering from inflammation, it mostly coagulates slowly enough to allow of the formation of the buffy coat, and sometimes so great is its resistance to coagulation, that it may remain fluid for several days first.

An interesting example is cited, in which the blood first drawn from a patient suffering under severe pneumonia did not coagulate for fifteen days, when it formed a coriaceous crust. This man was bled ten times, and after each bleeding, just as the inflammation shewed more disposition to yield, so did the blood coagulate more readily, and after the last venesections it did so in a few hours. Many of the cases of dissolved and incoagulable blood related by various authors have been mere examples of slow coagulation, in consequence of the persistence of the morbid process; and ignorance of this fact has led to the dangerous practice being so frequently followed of taking the indication for repetition of the bleeding from the ready coagulation of the blood, and the contra-indication from the persistence of its fluid condition!

"A question here at once arises. In what light are we to regard all the descriptions of non-coagulable blood consigned by authors in their histories of putrid and malignant diseases? Are we to reject them as false or admit them as characterizing diseases which are no longer met with? We incline to the belief that the excellent authors who have spoken of dissolved blood, and of blood which would not coagulate, have for the most part badly, or at least incompletely, observed, and have been induced by the condition of their own mind, or the influence of some dominant theory, too hastily to conjoin certain properties with certain physical appearances. And that such an error may have easily and frequently occurred, and will do so again, for a longer period than we could desire, the case above referred to suffices to prove. The blood at the first bleeding possessed all the characteristics by which the older physicians were accustomed to judge of it as dissolved and incoagulable, and indeed a practitioner of our own times, unless his attention had been called to the subject, would not have probably given a different opinion. What would be said of blood which had continued fluid for more than a week, and presented such an absence of the so-called plasticity as to allow of its being mixed together like so much serum, and which deposited at the bottom of the vessel a mass of deep coloured red globules destitute of all cohesion? Would it not be said that this was the dissolved blood of an adynamia, awanting in fibrinous principle, or tending to putrefactive dissolution? Well! This same blood, in process of time, presented the firmest crassamentum, and a most decided buffiness. So far, too, from furnishing signs of putrefactive decomposition, it did not exhibit these for a month, while an equal quantity of blood taken for an ordinary disease of the chest, and exposed side-by-side with it to the same air and temperature putrefied in a fortnight. The individual, likewise, who furnished this blood, so far from suffering under adynamia or any

cachexia, was the prey of a violent inflammation which the most active curativé measures, consisting of twelve bleedings of 12 ounces each practised in eight days, &c. &c. hardly sufficed to subdue; and nevertheless the cure took place after a very short convalescence, so that 20 days after he had been received at the hospital he was enabled to leave it again in full health.

"For a long time past I have used every diligence in our large hospital (at Milan) to discover some examples of this dissolved, non-coagulable, blood, as described by some pathologists; but I have not been able to find one solitary case, in which blood, left to itself for a sufficient time, and protected from external destructive influences, has not undergone a distinct coagulation, prior to putrefaction. Many of those I examined had remained for days in a fluid state, and many had all the appearances justifying completely the prediction of incoagu lability, resolution, &c.: but with some care I was always enabled to demonstrate the coagulability. More than once also it happened to me to see blood coagulate which had been taken from the veins of a body 36 or 48 hours after death. And in respect to this, I may observe in passing, that it seems to me that the conditions of rigor or relaxation of the parts of a dead body are in every case dependent upon the state of coagulation of the fibrine in its capillaries, whe ther this is accomplished, retarded, or re-dissolved.”—Vol. 113, p. 348.

The author details at some length the particulars of five of the cases observed by him in the hospital, and a hasty examination of which would have led to their being set down as examples of the dissolved state of the blood. He concludes by repeating his opinion that the coagulation of the blood prior to its putrefaction is in all cases inevitable; that the blood in scorbutus and typhus which authors have noted as exemplifying its dissolved condition, is blood more or less poor in fibrine, and more or less slowly coagulable; but that, according to the quantity and quality of the fibrine, it does coagulate sooner or later, and those who have not seen its coagulation and yet noted its putrefaction, have observed it too early or to late. For the expression of long-delayed coagulation he proposes the term Bradifibrina (Bpadus, slow), as merely indicating slowness, without implying any opinion as to the cause of this.

4. Rarefaction of the Fibrine (Parafibrina). From various experiments which he undertook the author concludes "" I that the fibrine of the blood may, under morbid circumstances, assume a lesser density, or become rarified; that fibrine so modified imparts its tenuity to the mass of the blood in which it exists; and that in such condition it at the least is of lesser density than is the albumen of the serum." This, however, does not hold good of all the fibrine of the blood contained in an organism suffering under inflammation, but probably can only be extended to all that of new formation, or which is directly produced by the inflammatory process itself. The blood in the normal state holds fibrine in solution, which by coagulating, renders the liquid residuum of a lesser density, as is the case with every solid body which had previously been dissolved in a liquid of lesser specific gravity. The fibrine rendered slow in coagulating by inflammation, bradifibrina, also renders the fluid more dense in which it is dissolved, and lessens its specific gravity upon separating from it. "But there is a third species of fibrine, which is the modified fibrine upon which we are now especially treating, and which has the peculiar property of rendering the liquid in which it is found specifically lighter. We propose

1847] Condition of the Fibrine of the Blood in Inflammation. 317

to term it Parafibrina, in imitation of the chemists who thus distinguish isomeric substances, or those which, preserving the same composition, are yet modified in their properties."

Parafibrine in general coagulates with exceeding slowness, so as even to surpass bradifibrine in that respect. Its coagulation, too, takes place in such slender filaments as to be hardly recognisable by the naked eye, and giving rise, together with the enclosed serum, to a mass possessing rather a gelatinous than a fibrous appearance. The delicate meshes thus formed may be to some extent compared to the cellular network which gives something like consistence to the albumen of the white of an egg, or to that which supports the vitreous humour of the eye; but, when separated by pressure from the serum it contains, it is found to be a fibrous tenacious body. The serum raised under the epidermis by blisters or slight scalds is especially rich in parafibrine, and its properties can be best studied in this fluid. When parafibrine coexists with ordinary fibrine or bradifibrine, it coagulates at a later period upon the surface of this as a gelatinous deposit of varying extent: and blood which retains its fluidity for a very long time always contains it. "There are cases in which the blood presents very little crust, although the crassamentum possesses great consistency, and is covered with a thin stratum of a tremulous gelatiniform buff. The production of parafibrine in such cases does not seem to be accompanied by a proportionate augmented quantity of ordinary fibrine, or with the production of bradifibrine. The three modifications of fibrine now noticed may exist independently of each other in a given specimen of blood, and in very different quantities; just as they may all three exist in the same blood, likewise in different proportions."

Signor Polli adverts to the fact of Hewson and Dr. John Davy having already expressed their opinions, that the production of the buffy coat is in some measure due to the greater tenuity of the fibrine; but infers, from a passage in Mr. Wharton Jones' Report in 1843, that these had received little or no sanction among their own countrymen.

Applications." The character we have recognised in Parafibrine, of possessing a greater tenuity than the serum in which it is found liquified, furnishes the explanation of a pathological phenomenon of great moment; I mean of the fibrinous or plastic transudation, and the sero-fibrinous transudation which constitute the termination of the greater part of the membranous inflammations. Great surprise has always been excited by the dense strata of fibrine which have been found on membranes which have undergone inflammation, and the large pseudo-membranes or flakes of coagulable lymph which are seen swimming in the serum contained in the cavities of inflamed membranes; and the explanation of these familiar facts has continued a desideratum.

"It certainly was far easier to imagine that extravasated serum became coagulated, than to believe that fibrine, which out of the blood-vessels is the body to which the blood owes its consistency, tenacity, and durability, could pass through the walls of the vessels. Nevertheless, it is demonstrated that not only are these morbid transudations of a truly fibrinous nature, but that they transude through the vessels, and coagulate sooner or later, just as does blood which has been drawn. If we examine these products in the dead body, we certainly only find them in their solid form; but the evidence of practitioners is not wanting to shew that, in the fluid evacuated from the chest during life for a pleurisy, the serum has been found in a short time the consistency of a jelly. So, again, pus

evacuated in empyema or abscess has, after a while, separated itself into clot and serum; serum evacuated for ascites supervening on peritonitis, or from a hydrocele consequent upon inflammation of the tunica vaginalis, has been converted by coagulation into a tremulous mass. That kind of gelatiniform crust which often covers the surface of blistered parts is but a fibrinous deposit, which, at the beginning, consisted of but a very fluid exudation."-Vol. 113, p. 367.

The author adds that this lightness and tenuity of the parafibrine furnishes also an explanation of a fact which may sometimes be observed in certain stages of inflammation, and which by some has been adduced as an argument in opposition to the law of the formation of the buff of the blood laid down in the foregoing pages-viz. the case in which a thick buffy coat is found on blood which has coagulated with a certain amount of promptitude. Suppose that in such blood there exists a sufficient amount of parafibrine to rarify the fluid, and that it has been drawn after several prior emissions; being thus greatly diluted and quickly coagulable, the conditions are present which permit the red globules to rapidly descend, leaving on the surface a clear stratum of fibrine, which also, after a little time coagulating, may give a thick buff.

The following are some of Dr. Polli's observations upon the conclusions to be drawn from the different appearances of the fibrine.

"These various modifications of the fibrine seem not only to characterize inflammation in the most distinct manner, but each seems to connect itself with a particular degree of intensity of the inflammatory process. Thus: the simple increase of the quantity of the fibrine indicates the development of the first stage of an inflammation, the extension of which will be measured by the proportionate excess of this material. The retardation of the coagulation indicates an aggravated degree of the inflammatory process, inducing that modification in the fibrine we have termed bradifibrina. Lastly, the highest degree of a phlegmasia gives rise to that modification, by reason of which the blood presents the gelatiniform crust, dependent upon the production of parafibrine.

"If the coagulum forms with sufficient promptitude to prevent buffiness, and does not give it even when coagulating somewhat slowly from its great density, but is itself consistent and hard, it is an indication that in such blood there is simple excess or abundance of fibrine. The phlogosis is only in its first stage, and it will become more or less extended in proportion as the quantity of fibrine is increased. If there is a clot not only consistent and hard, but likewise furnished with a thick stratum of a white coriaceous crust, this having been formed by a proportionally slow coagulation, this is an indication not only that there is an inflammation of some extent, but that it has reached that higher degree of intensity, in which a certain quantity of bradifibrine is produced. If, on the contrary, the crassamentum is observed to possess but slight consistency, approaching in that respect to a normal condition, but that it possesses a little of the gelatiniform crust or buff, the inflammation which so modifies the blood has reached its highest degree of intensity, but is circumscribed; while we must regard it as both intense and extensive when this gelatiniform crust of parafibrine is abundant, and also accompanied by a greater or less share of bradifibrine. This highest degree of the inflammatory process may exist in some points of a tissue and manifest itself as just stated, while in other portions of the same tissue a milder phlogosis, competent only to lead to the two other modifications of the fibrine, may be pursuing its course. Thus we may have at the same period the tissues invaded by an inflammation which for a long period is confined to its first degree of intensity; other portions affected with greater, or, as we may call