420 



On the Origin of Fibrin Ferment, [Mar. 6V 



succeeding coagulation is observed some time later, to be followed in 

 turn by a third, and so on. When lecithin, on the other hand, is 

 added, without previous dilution, the clotting is speedy and complete. 



If the serum thus resulting from the coagulation of peptone-plasma 

 brought about by large dilution and treatment with carbonic acid, be 

 examined for fibrin ferment in the usual way, it will be found to con- 

 tain ferment, though much less than could be obtained from a corre- 

 sponding quantity of the same plasma coagulated rapidly by the add ition 

 of lecithin. The relative amount of ferment appearing under different 

 circumstances is illustrated by the following experiment : — 



Of three equal portions of the same peptoue-plasma, one portion 

 was simply treated with a stream of carbonic acid gas, without any 

 dilution, and did not coagulate : a second was treated with a stream 

 of the same gas after large dilution, and coagulated slowly ; to a third 

 lecithin was added, and a stream of carbonic acid passed through it, 

 with the result of producing a rapid and complete coagulation. 



All three portions were treated in the same way for the extraction 

 of the fibrin ferment, and the activity of the three aqueous extracts 

 then prepared was tested under exactly the same conditions, with 

 the help of magnesium sulphate plasma. 



The first produced no coagulation after the lapse of twenty hours. 



The second produced coagulation in four hours. 



The third produced coagulation in five minutes. 



The amount of ferment seems to be in proportion to the energy of 

 coagulation and the presence of ferment after simple dilution, and the 

 action of carbonic acid gas shows that the ferment appearing after 

 coagulation by the help of lecithin does not come from the lecithin 

 itself. 



Thus there is a remarkable coincidence between the occurrence of 

 coagulation itself and the appearance of the fibrin ferment, and that 

 in plasma freed most carefully from all cellular elements. 



I believe, therefore, that I am justified in concluding that though 

 fibrin ferment does not pre-exist in normal plasma, it may make its 

 appearance in that plasma in the absence of all cellular elements, 

 and must therefore come from some constituent or constituents of the 

 plasma itself. 



I am still engaged in investigations directed to find out what that 

 constituent is, or what those constituents are. 



