ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTERS. 185 



the principal constituents of the blood in health, according to 

 .ode of estimating them ( 152). 



of variation for 

 the foregoing mode 



Fibrin . ' , . . . from 2 to 3 parts per 1000. 



Red Corpuscles . . . . " 110 " 152 " " 



Solids of Serum . - . . " 72 88 



Water . . . && . " 760 " 815 " " 



171. The first of these components whose variations we shall consider, is 

 Fibrin; the estimate of which, however, is open to an important fallacy, that 

 has not been sufficiently guarded against namely, the admixture of the Color- 

 less corpuscles. "These," as Mr. Paget correctly remarks, "cannot, by any 

 mode of analysis yet invented, be separated from the fibrin of mammalian 

 blood ; their composition is unknown, but their weight is always included in the 

 estimate of the fibrin. In health, they may, perhaps, add too little to its weight 

 to merit consideration; but in many diseases, especially in inflammatory and 

 other blood-diseases in which the fibrin is said to be increased, these corpuscles 

 become so numerous that a large proportion of the supposed increase of the 

 fibrin must be due to their being weighed with it. On this account, all the 

 statements respecting the increase of fibrin in certain diseases need revision." 1 

 Some idea may probably be formed of the relative proportion of fibrin and 

 colorless corpuscles, in the colorless coagulum obtained by stirring the blood or 

 by washing the ordinary clot, or in that which forms the "buffy coat" ( 189), 

 by attending to its texture; for where this is unusually firm and almost leathery, 

 as it commonly is in the blood of a person suffering under a "sthenic" inflamma- 

 tion, either the proportion of fibrin must be augmented, or its plasticity must 

 be increased, or both conditions must co-exist; whilst, on the other hand, when 

 the colorless clot, though bulky, is deficient in tenacity and is easily broken 

 down between the fingers, as happens with that of blood drawn from tubercular 

 subjects when no inflammation is present, the increase is probably due rather to 

 an augmentation in the colorless corpuscles, than to that of the fibrin. In the 

 results of the analyses now to be stated, it must be borne in mind that the term 

 "fibrin" really designates the "colorless coagulum" of spontaneous formation, 

 whatever may be its composition. 



172. The most important fact substantiated by Andral is one that had been 

 previously suspected the invariable increase in the quantity of Fibrin during 

 acute Inflammatory affections; the increase being strictly proportional to the 

 intensity of the inflammation, and to the degree of symptomatic fever accom- 

 panying it. "The augmentation of the quantity of Fibrin is so certain a sign 

 of Inflammation, that if we find more than 5 parts of fibrin in 1000, in the 

 course of any disease, we may positively affirm that some local inflammation 

 exists." Several cases are mentioned, in which an increase to 7 or 7z parts 

 took place, without any apparent cause; but in which it afterwards proved that 

 severe local inflammation had been present; and thus we are furnished with a 

 pathognomonic sign of great importance. The average proportion of Fibrin in 

 Inflammation may be estimated at 7; the minimum at 5; the maximum at 13.3. 

 The greatest augmentation is seen in Pneumonia and Acute Rheumatism. It 

 does not appear that in robust athletic persons, the proportion of Fibrin is 

 greater than in those of feeble constitution; in the latter it is the Corpuscles 

 that are deficient : and it is rather from this disproportion, than from an abso- 

 lute excess of Fibrin, that their greater liability to Inflammatory affections 

 arises. Diseases which commence at the same time as the Inflammation, or 

 which coexist with it, do not prevent the characteristic increase of the Fibrin; 

 thus in Chlorotic females, the proportion rises to 6 or 7, under this influence. 



1 Kirkes and Paget's "Manual of Physiology," p. 57. 



