482 THE BLOOD. 



particles, coming together, constitute with the blood-corpuscles and 

 serum, in ordinary coagulation, the red clot; and the after separation of 

 the serum is due to the contraction of the fibrin, by a continuance of 

 the same process. 



" (6) In cases where blood coagulates with its fibrin partly or wholly in 

 an isolated form, the effect arises either from an excess of fibrin, or 

 from slow coagulation (the result of slow elimination of the solvent), 

 or from rapid subsidence of the red corpuscles, or from a combination 

 of these causes ; the particles of fibrin are thus brought together in 

 mass, and rise to the surface. 



" (c) The imperfect coagulability of blood, under the abnormal condi- 

 tions specified in preceding pages, is due, according to the case, either 

 to an absolute deficiency of fibrin, or to slow evolution or excess of its 

 volatile solvent." 



Mr Lister, now Kegius Professor of Surgery in Glasgow, 

 has, I think, justly insisted on the process of coagulation as 

 being influenced materially by the contact of blood with 

 living tissues. It is not merely a physical change, as we 

 find that blood does not coagulate when exposed for a con- 

 siderable time to the air in contact with tissue recently 

 obtained from an animal, and, therefore, retaining certain 

 properties which may be justly called vital. Indeed, Mr 

 Lister has even demonstrated, that in blood removed from 

 the body, blood does not coagulate in obedience to the laws 

 established by the 'ammonia' theory. Though occupying 

 much space, still I think the quotation of Mr Lister's last 

 paper on the subject of considerable moment. 



In this paper, read at a meeting of the Medico-Chirurgical 

 Society of Edinburgh, on the 16th of November, 1860, Mr 

 Lister said: 



" I take this opportunity of demonstrating what appears to be a 

 point of considerable importance with reference to the coagulation of 

 the blood, a subject to which my attention has been again directed 

 by the recurrence of that period of the Session in which the funda- 

 mental principles of pathology are discussed in a course of surgical 

 lectures. 



