LOCAL FORMATION OF FIBREfE. 197 



the force of the current of the blood, to induce the 

 fibrine to transude directly as it is wont to do in certain 

 inflammatory processes ; for this some irritation is 

 always required. The greatest obstructions may be in- 

 duced in the circulation, exudations of serous fluids may 

 be experimentally produced upon the largest scale, but 

 that peculiar fibrinous exudation which the irritation of 

 certain tissues provokes with so much ease, never ensues 

 upon these occasions. 



That the fibrine in the blood itself is produced by a 

 transformation of the albumen, is a chemical theory, 

 which has no other evidence in its favour than the fact 

 that albumen and fibrine have a strong chemical resem- 

 blance, and that, on comparing the questionable formula 

 for fibrine with the equally questionable one for albu- 

 men, it is very easy to imagine how, by the abstraction 

 of a couple of atoms, the transition from albumen to 

 fibrine might be effected. But our being able in this 

 manner to deduce one of the formulae from the other 

 does not afford the slightest proof that an analogous, 

 transformation occurs in the blood. It may possibly 

 "take place in the body, but even then it would at any 

 rate be more probable that it was accomplished in the 

 tissues, and that from them the fibrine was conveyed 

 away into the blood by means of the lymph. This is, 

 however, the more doubtful, because rational formulae 

 for the chemical composition of albumen and fibrine have 

 not yet been determined, and the incredibly high atomic 

 numbers in the empirical formulae point to a very com- 

 plex grouping of the atoms. 



Let us therefore hold fast the well-ascertained fact 

 that fibrine can only be made to exude upon any surface 

 by the occurrence of some irritation, that is, local 

 change, in addition to the disturbance in the circulation. 

 This local change, however, is, as results from experi- 



