1884.] 



On the Origin of Fibrin Ferment. 



419 



the exact time elapsing between the addition of ferment and the 

 appearance of the clot, but it was certainly not longer than three or 

 four hours. 



II. Of the so-called peptone-plasma (i.e., plasma of the blood of a 

 dog after the injection of peptone into the veins, such blood, as is 

 well known, coagulating with great difficulty), freed from all cellular 

 elements by the centrifugal machine, two portions were taken. 



To the one (A) a quantity of lecithin was added, the lecithin being 

 rubbed up with the plasma so as to be diffused through it ; the other 

 (B) was left untouched. 



Through both a stream of carbonic acid was passed, with the result 

 that while A clotted in about ten minutes, B after the lapse of half 

 an hour showed no disposition whatever to coagulate. Both portions 

 were then treated with excess of alcohol for the extraction of fibrin 

 ferment in the usual way. The aqueous extract of A proved to be 

 exceedingly rich in ferment, producing coagulation in magnesium 

 sulphate plasma in about ten minutes. The similarly prepared 

 aqueous solution of B produced no coagulation at all. 



Now I have elsewhere * in discussing the action of lecithin in pro- 

 moting coagulation, shown that the coagulation which is brought 

 about by the addition of lecithin is not due to the lecithin or to any 

 of its products of decomposition acting after the manner of a ferment, 

 or to its carrying a fibrin ferment with it. In this case, therefore, as 

 in the previous case of " salted " plasma, the ferment appears to be 

 absent before coagulation, but to be present after coagulation. 



I may here call attention to an observation made by Rauschenbach.t 

 This observer found that the addition of yeast to plasma, prevented 

 from coagulating by exposure to cold, brought about coagulation, and 

 at the same time gave rise to the appearance of a large quantity of 

 fibrin ferment. Nevertheless, he completely failed to extract any 

 fibrin ferment from the yeast itself. Now yeast is very rich in 

 lecithin, and it seems highly probable that the coagulation caused by 

 yeast was due to the lecithin contained in it, and hence the appear- 

 ance of the fibrin ferment after the addition of yeast, and consequent 

 coagulation, is quite parallel to the result of the experiment with 

 lecithin and peptone-plasma recorded above. In both cases the 

 ferment appears to have arisen out of the plasma itself. 



It is possible to obtain a coagulation in peptone-plasma without 

 the addition of lecithin. For this purpose large dilution is necessary, 

 followed by the passage of a stream of carbonic acid gas. But in such 

 a case, however, coagulation is not only long in making its appearance, 

 but the fibrin is formed, so to speak, in successive crops. Thus a feeble 

 coagulation first appears, and if the clot so formed be removed, a 



* " Journ. of Physiol.," vol. iv. p. 226. 

 f " Blutplasma u. Protoplasma," Inaug. Diss., Dorpat. 

 VOL. XXXVI. 2 G 



