36 SOURCE OF THE FIBRIN-FACTORS, 



state. Neither he nor Schmidt asserts that this body is of the nature of a ferment, 

 although they use the term for convenience. It is quite certain that fibrin may be 

 formed when no fibrino-plastin is present, coagulation being caused by the addition 

 of calcic chloride or casein prepared in a special way. But, whether one or two 

 proteids -be required, in all cases it is clear that a certain quantity of salts, 

 especially of NaCl, is necessary.] 



[The main drift of the foregoing evidence points to the presence of one proteid 

 fibrinogen in the plasma, which under certain circumstances yields fibrin. In 

 shed blood this act seems to be determined by a ferment, perhaps derived from the 

 disintegration of colourless corpuscles.] 



[Theory of Wooldridge. Wooldridge attributes great importance to lecithin. In shed 

 blood the coagulation is brought about by the interaction of the plasma and the colourless 

 corpuscles. If lecithin (which is present in considerable amount in the colourless corpuscles) 

 diffuses into the blood, coagulation takes place. When peptone is injected into the blood of 

 the dog, the blood does not clot ; this is due, according to Wooldridge, to the peptone 

 " preventing the interaction of leucocytes and plasma." If, however, the corpuscular elements 

 ire removed by the centrifugal machine, the peptone-plasma can be made to clot. He also 

 believes that fibrin-ferment does not pre-exist in normal plasma, but that " 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."] 



30. SOURCE OF THE FIBRIN-FACTORS. Al. Schmidt maintains that all 

 the three substances out of which fibrin is said to be formed, arise from the break- 

 ing up of colourless blood-corpuscles. In the blood of man aud mammals, fibrinogen 

 exists dissolved in the circulating blood as a dissolution-product of the retrogressive 

 changes of the white corpuscles. Plasma contains dissolved fibrinogen and serum- 

 albumin. The circulating blood is very rich in colourless blood-corpuscles, much 

 richer, indeed, than was formerly supposed. As soon as blood is shed from an 

 artery, enormous numbers of the colourless corpuscles are dissolved according to 

 Al. Schmidt 71*7 per cent, (horse). First the body of the cell disappears, and 

 then the nucleus. The products of their dissolution are dissolved in the plasma, 

 and one of these products is fibrino-plastin. At the same time the fibrin-ferment 

 is also produced, so that it would seem not to exist in the intact blood-corpuscles. 

 Fibrino-plastin and fibrin-ferment are also produced by the " transition forms " of 

 blood-corpuscles, i.e., those forms which are intermediate between the red and the 

 white corpuscles. They seem to break up immediately after blood is shed. The 

 hlood-plates (p. 16) are also probably sources of these substances. 



In amphibians and birds the red nucleated corpuscles rapidly break up after blood is shed, 

 and yield the substance or substances which form fibrin. Al. Schmidt convinced himself that 

 in these animals fibrinogen is originally a constituent of tne blood-corpuscles. 



It is clear, therefore, according to Schmidt's view, that as soon as the blood- 

 corpuscles, white or red, are dissolved, the fibrin-factors pass into solution, and the 

 formation of fibrin by the interaction of the three substances will ensue. 



If a large number of leucocytes be introduced into the circulation of an animal, 

 the leucocytes are dissolved in great numbers in the blood, so that death takes 

 place by diffuse coagulation. Should the animal survive the immediate danger of 

 death, the blood, owing to the want of leucocytes, is completely incapable of 

 coagulating (Groth). 



[And. Buchanan thought that the potential element of his "washed blbpd-clot" resided in 

 the colourless corpuscles, "primary cells or vesicles." He, like Schmidt, found that the 

 buffv coat of horses' blood, which is very rich in white corpuscles, produced coagulation rapidly. 

 I'.ik hanan compared the action of his washed clot to that of rennet in coagulating milk.] " 



Pathological Al. Schmidt and his pupils have shown that some ferment, probably derived 

 from the dissolution of colourless corpuscles, is found in circulating blood, and that it is more 

 abundant in venous than in arterial blood, while it is most abundant in shed blood. It is 

 specially remarkable that in septic fever the amount of ferment in blood may increase to such 

 an extent as to permit the occurrence of spontaneous coagulation (thrombosis), which may even 

 produce death (Arn. Kbhhr). In febrile cases generally, the amount of ferment is somewhat 



