50 SCHMIDT'S RESEARCHES ON THE FIBRIN-FERMENT. [LOOK i. 



But whence comes the ferment? Schmidt received the blood 

 as it flowed from the blood-vessels of a living animal directly into 

 absolute alcohol and then subjected the product to the process 

 followed in the separation of the fibrin-ferment, and found that the 

 solution obtained under these circumstances was free from any ferment 

 action, and he therefore concluded that the ferment is generated in 

 the blood after it is withdrawn from the blood-vessels. But how 

 generated? Many facts conspired to connect the formation of 

 ferment with the colourless corpuscles of the blood. 



Schmidt found that liquids coagulate more or less rapidly, very 

 much according as they contain many or few colourless corpuscles; he 

 found that horse plasma, diluted with ice-cold water and filtered 

 from all corpuscles, coagulates not only much more slowly but also 

 much more feebly than the same plasma unfiltered; that in cooled 

 horse plasma from which the corpuscles have subsided, the upper lay- 

 ers, most free from corpuscles, coagulate more imperfectly, yielding 

 actually less fibrin than the lower, richer in corpuscles, and that such 

 plasma free from corpuscles, when subjected to the process for 

 separating fibrin-ferment, yields a solution comparatively inactive, 

 when compared with a solution prepared from plasma rich in 

 corpuscles. Moreover Schmidt found that by adding paraglobulin to 

 the above plasma the yield of fibrin was increased. 



Furthermore Schmidt thinks he has proved that in the short 

 interval which, at ordinary temperatures, intervenes between the 

 shedding and coagulation of the blood there is a rapid breaking down 

 of colourless cells and of cells which appear in some way intermediate 

 between the colourless and coloured cells, which are nucleated like 

 colourless cells, but whose protoplasm is tinged with haemoglobin. 

 He therefore has come to the conclusion that the coagulation of the 

 blood is due to the union of fibrinogen, which exists preformed in the 

 plasma, with paraglobulin derived from the colourless corpuscles a 

 union which takes place under the influence of a ferment-like body 

 which also arises in the same cells, and which like paraglobulin is de- 

 rived from them in the short interval which elapses before coagulation. 



In their latest developments the views of Schmidt approach 

 much more closely to those of the man w r hose facts and theories have 

 both been buried in oblivion, Dr Buchanan. Both observers look 

 upon coagulation as due to a ferment-like action, exerted upon a 

 constituent of the plasma, which is, in the living body, dissolved in 

 that fluid ; both connect that ferment action with the colourless cells 

 of the blood, and Schmidt adds definiteness to the older views of 

 Buchanan by connecting the ferment action with the actual breaking 

 down of those bodies. 



The chief point of divergence the one element in Schmidt's 

 theory which had no place in Buchanan's relates to the accessory 

 body paraglobulin, whose existence he did not even surmise, much less 

 consider to be essential to the formation of fibrin. But is it essential? 



