bit. Hichanan on the Coagulation of the Blood. V.) 



stoppered phial. Thus kept, I have found it to retain for several 

 months its power of coagulating fibrin. The serum of hydrocele is 

 the more coagulablo the fresher it is. It sometimes soon loses its 

 coagulability on being kept, but more frequently retains it till putre- 

 faction is far advanced. There is, therefore, no difficulty for any one 

 repeating those experiments, and satisfying himself of their truth. 



Tho experiment which I have described is very analogous to some 

 experiments which I performed in the year 1831, and of which I 

 afterwards published an account in the M London Medical Gazette," 

 (April 9, 1836.) I then showed, that if the clot of blood reduced to the 

 liquid state by kneading and expression through a linen cloth, be 

 mixed with hydrocelic serum, the mixture recoagulates into a perfectly 

 homogeneous solid mass, which, like the ordinary coagulum of blood, 

 becomes florid on exposure to the air : and that if a portion of coagu- 

 lum not so disintegrated be put into a vessel containing hydrocelic 

 serum, a web of fibrin is gradually spun around the coagulum. I 

 showed that these effects were not due to the colouring matter of the 

 clot; but I did not try the effect of the washed clot, my attention 

 having been called in a different direction, by finding that pure serum 

 of blood and hydrocelic serum when mixed together underwent coagu- 

 lation. On since discovering the efficacy of tho washed clot in causing 

 coagulation, I thought it probable that the minute solid particles, which 

 the microscope never fails to detect in the serum of blood, were the 

 agents to which the coagulation of the two kinds of serum when mixed 

 together ought to be ascribed. This corresponded well with the ob- 

 servation which I had long before made, that the deeper the red tint 

 of the blood-serum employed in the experiment, the better does it suc- 

 ceed. On the other hand, Dr. Anderson, in his paper " On the state 

 in which fibrin exists in the blood,"* has shown that if the mixed 

 liquids be carefully filtered, so that no solid particles can any longer 

 be detected by the microscope, coagulation nevertheless ensues ; thus 

 rendering it probable that the coagulating principle exists in the 

 serum of blood not as a solid but in a state of solution. It may, how- 

 ever, be objected to this experiment, that the blood-corpuscles pass 

 through any filtering paper, however dense ; and that it is impossible 

 by filtration, to deprive turbid serum of the solid particles mechanically 

 diffused through it. 



In the summer of last year, after I had satisfied myself as to the 

 power of the washed clot in causing coagulation, I tried the effect of 

 tho buffy coat of the blood, reduced to minute shreds, and diffused 

 through the hydrocelic liquid, and found it, in numerous instances, to 

 have a similar power. I even found, that the dried buffy coat from 

 the blood of a horse, which I had kept for several months, on being 

 pulverized and mixed with the liquid, induced coagulation. I found 



* Proceedings of Phil. Soc. of Glasgow, vol. i. p. 201. 



