1863.] 605 



must be attributed not to any loss of power in the vein, but simply 

 to the action of the foreign solid. 



In seeking for an analogy to this remarkable effect of ordinary 

 solids upon the blood, we are naturally led to the beautiful observa- 

 tions of Professor Graham, lately published in the Philosophical 

 Transactions. He has there shown what insignificant causes are 

 often sufficient to induce a change from the fluid or soluble to the 

 "pectous," or insoluble condition of "colloidal" forms of matter. 

 Indeed Mr. Graham has himself alluded to the coagulation of fibrin 

 as being probably an example of such a transition. 



There is, however, another remarkable circumstance that must be 

 taken into consideration, of which I myself have been only recently 

 aware, and which may be new to several Fellows of the Society ; and 

 that is, that in spite of the influence of an ordinary solid the liquor 

 sanguinis is not capable of coagulating per se. It was observed 

 many years ago by my colleague, Professor Andrew Buchanan, of 

 Glasgow, that the fluid of a hydrocele, generally regarded as mere 

 serum, coagulated firmly if a little coagulum of blood diffused in 

 water was added to it an effect which he was disposed to attribute 

 to the agency of the white corpuscles*. I repeated Dr. Andrew 

 Buchanan's observations last year, and satisfied myself first that the 

 diffused clot did not act simply by providing solid particles to serve 

 as starting-points for the coagulating process. I tried various 

 different materials in a finely divided state, and found that none of 

 them, except blood, produced the slightest effect. But I found that 

 if a mixture of serum and red corpuscles from a clot was added 

 to some of this hydrocele-fluid, it was soon converted into a firm 

 solid mass. If a small quantity of the serum and corpuscles was 

 dropped into the fluid and allowed to subside without stirring, coagu- 

 lation rapidly took place in those parts where the red corpuscles 

 lay, while other parts of the fluid remained for a long time un- 

 coagulated. This seemed to indicate that the red corpuscles had 

 a special virtue in inducing the change. I confess, however, that 

 till very lately I was inclined to suppose that in the hydrocele-fluid 

 the fibrin must be in some peculiar spurious form. We know that the 

 buffy coat of the horse's blood coagulates in a glass without addition 

 of clot, and we know that lymph coagulates ; so that I did not doubt 



* Proceedings of the Glasgow Philosophical Society, February 19, 1845. 



