1887.] 



On a New Constituent of Blood Serum. 



231 



fibrin, and only differs from the latter chemically by being more easily 

 soluble in dilate alkali. It is totally different from the soft granular 

 precipitate of paraglobulin, the latter substance being extremely 

 easily soluble in the slightest excess of acid. It is also constantly 

 present in serum of sheep's blood. In the case both of dog's blood 

 and sheep's blood it is only present in very small amount, and in the 

 serum from horse blood and bullock's blood it was absent in the 

 specimens I have examined. The physiological interest of this 

 substance will be seen from the following. 



It' is well known that Schmidt regarded two proteid substances as 

 being essential for coagulation. One of these bodies was para- 

 globulin, a substance existing in large quantity in blood serum. 

 Subsequent investigation has failed to confirm this view, and there 

 can be no doubt that paraglobulin is not essential to the process. 

 But Schmidt has obtained results, the correctness of which we are in 

 no way entitled to dispute, which apparently clearly show that the 

 quantity of fibrin formed can be largely increased by the addition of 

 paraglobulin. I think this discrepancy can be explained by the help 

 of this new substance, and this will be best shown by describing the 

 following experiments. 



Two portions of peptone plasma were taken, and 



To No. 1, an equal quantity of sheep's serum was added. 

 ,, No. 2, a small quantity of a solution of the new substance. 

 No. 1, after many hours only presented a scarcely perceptible 



flocculus of fibrin. 

 No. 2 was quite solid in 15 minutes ; on squeezing out the fluid 



from the clot and again adding a solution of the new substance, 



the mixture again clotted through and through. 



Now Schmidt's experiments were very much of this nature. He 

 found in certain specimens of hydrocele fluid that the addition of 

 fibrin ferment produced very slight clotting, whereas on the further 

 addition of a substance which he regarded as paraglobulin a decided 

 clotting took place. Now sheep's serum contains plenty of para- 

 globulin and plenty of fibrin ferment, but it has no appreciable 

 effect in my experiments. 



But this new substance, which it must be remembered is only 

 present in very small quantity in serum, had the most marked 

 influence, and hence I conclude that it is the new substance, and not 

 paraglobulin, which increases the amount of fibrin. It may be 

 mentioned that in preparing paraglobulin a certain amount of the 

 new substance is always precipitated with the former substance. 



A second physiological property of this new substance is the effect 

 it exerts when injected into the circulation of a living animal. 



It is very exceptional to find that the injection of blood serum 



