1885.] Fibrin-yielding Constituents of Blood Plasma. 261 



The following observations refer to such a plasma in which the 

 peptonisation is very complete, and from Avhich the body separable by 

 cooling has been removed. 



Behaviour of the Plasma towards Fibrin Ferment and Serum* 



In the vast majority of cases, the plasma gives with either of the 

 above only a very minimal clot, a few scarcely perceptible threads or 

 membranes being the sole result of prolonged action. Serum is not 

 more effectual than ferment. 



But if, after the addition of serum or ferment, a stream of carbonic 

 acid be passed through the plasma, or the plasma be diluted with 

 several times its volume of water, it clots through and through, 

 becoming quite solid. 



The readiness with which coagulation takes place with C0 3 varies 

 in different specimens, sometimes very rapidly, sometimes more slowly ; 

 sometimes it only occurs when the C0 2 treatment and dilution are 

 combined. 



There are two exceptions to the above statement : — 

 Firstly — Sometimes neither ferment nor serum give by themselves 

 the slightest trace of a clot in the plasma. 



Secondly — They sometimes give a very considerable clot. 

 Both these exceptions are rare. 



Now, I take these experiments to show that the plasma contains a 

 certain very small amount of true fibrinogen (coagulable with serum). 

 In some cases even this small trace may be absent, in others it may 

 be considerable. But the bulk of the coagulable matter of the plasma 

 is not directly coagulable with serum. It is a body which is readily 

 altered so as to clot with the serum or ferment. This alteration can 

 be effected by dilution, by C0 2 , or in the process of isolation. The 

 body is not fibrinogen, but it readily passes into the latter. 



I now turn to another kind of plasma which gives like results, 

 but which is free from the objection that in peptone plasma the 

 proteids become altered by the peptone injection — an objection which 

 I do not think to be at all justified by the facts. For the sake of con- 

 venience, I call it NaCI plasma. It is obtained by receiving blood 

 direct from the artery into a 10 per cent, solution of common salt, 

 equal quantities of blood and salt solution being taken. 



It is essential that the blood should be mixed with the salt solution 

 with as little delay as possible. Very frequently the plasma obtained 

 from this blood is a little stained with haemoglobin. 



Now if to this plasma ferment be added, a certain amount of 

 clotting rapidly takes place ; it is usually very inconsiderable. On 



* Serum from clog's blood. Ferment prepared from serum (dog's) according to 

 Schmidt's method. The dry powder is added directly to the plasma, to avoid the 

 effect of dilution. 



