64 CHEMICAL COMPONENTS OF THE HUMAN BODY. 



men and Fibrin, gives rise to changes in their condition, and probably also in 

 their composition, which indicate a transition towards the gelatinous type. 

 When Fibrin is thus treated, two new substances are produced, one of which is 

 taken up by the water, whilst the other remains insoluble j the former is spoken 

 of by Mulder as a tritoxide of protein, and the latter as a binoxide ; but the 

 propriety of these designations is extremely doubtful. When Albumen is thus 

 treated, only the (so-called) tritoxide is produced ; and the insoluble residue is 

 still albumen. Whatever may be the real composition of these substances, their 

 presence in the living body, and their artificial production from the protein- 

 compounds, give them an indubitable importance. The tritoxide of protein is, 

 like gelatin, readily soluble in water, and is insoluble in alcohol and ether ; it 

 is precipitated from its solution by dilute mineral acids, chlorine-water, tannic 

 acid, corrosive sublimate, and most of the salts of the metallic oxides ] but it is 

 not thrown down by dilute acetic acid, by neutral alkaline salts, nor by that 

 very delicate test for the ordinary protein-compounds ( 18), ferrocyanide of 

 potassium. When dried, it is easily pulverizable ; but when moist, it is tough, 

 viscid, and capable of being drawn out in threads ; and when warmed, it has 

 an odor resembling that of gelatin. It is probable that a small quantity of this 

 substance always exists among the " extractive matters" of the Blood ; but it 

 maybe obtained in considerable amount from the " buffy coat" of inflammatory 

 blood ; and when its presence was first detected there, it was mistaken for 

 gelatin, so similar are its properties. According to Mulder, it is chemically 

 identical with the substance termed pyin, which was discovered by Griiterbock in 

 pus ; and it is a very significant fact, that the basis of false membranes, and 

 that of the skin of the foetus, both of them being fibrous tissues in an incipient 

 grade of formation, have been considered to bear a closer resemblance to pyin 

 than to any other organic compound. It may be anticipated, then, that more 

 accurate investigations in regard to the composition and physiological relations 

 of this substance, may help to bridge over the hiatus which at present exists 



foetus, none in the egg, none in the chyme, and less in the blood of the carnivora (who 

 feed on it) than in that of the herbivora. 



Some of these facts, derived from very different sources, appear quite inexplicable on 

 the theory that fibrin is essential to the progressive development of the tissues ; and the 

 opposite inference seems unavoidable, that it must be considered an excrementitious pro- 

 duct, derived from the waste of the tissues or the oxidation of the blood, and in progress 

 of elimination from the system. This conclusion, carried into the domain of pathology, 

 would lead us to suppose that an augmented proportion of fibrin in the blood (whether 

 occurring in active disease, or within the limits of apparent health) can be taken as an 

 indication only of increased labor and waste in certain elements of the body, not of an 

 increased development in the resources and nutrition of the blood. And on the same 

 grounds it would appear that a super-fibrination of the blood, in acute inflammatory dis- 

 eases, must be regarded as a consequence and effect of those diseases, not as their cause, 

 and not as a primary affection. ' ED.] This doctrine seems to the Author to be completely 

 opposed by the whole physiological history of Fibrin, and more particularly by the gradual 

 development of this ingredient in chyle, during its onward progress towards the sangui- 

 ferous system ; whilst, again, it seems to be entirely negatived by a comparison of the 

 condition of fibrin with that of the known products of the disintegration of the tissues, 

 such as urea or creatin, in which we see a marked tendency to the reproduction of purely 

 physical and chemical conditions (and this pre-eminently in their crystalline aggregation), 

 to the exclusion of those of vitality. We shall see that these last, although we know that 

 they must be continually passing through the blood, are eliminated from it with such 

 jealous care, that, in the healthy state, they scarcely accumulate in sufficient amount to 

 be detectable ; it is scarcely conceivable, therefore, that fibrin, if a product of disintegra- 

 tion, on its way out of the system, should accumulate in the blood to the extent of 

 between 2 and 3 parts in 1000. For an examination of the objections brought by Mr. 

 Simon against the commonly-received view, the reader is referred to the " Brit, and For. 

 Med.-Chir. Rev." vol. vii. p. 478. 



Simon's "Lectures on General Pathology," pp. 44-45, Am. Ed. 



