SOURCES OF THE FIBRIN-FACTORS. 47 



retrogressive changes of the white corpuscles. Plasma contains 

 dissolved fibrinogen and serum-albumin. The circulating blood is 

 very rich in lymph or white cells, much richer, indeed, than was 

 formerly supposed (Schmidt, Landois). As soon as blood is shed from 

 an artery, enormous numbers of the colourless corpuscles are dissolved 

 (Mantegazza) according to Alex. Schmidt 71*7 per cent, (horse). 

 First, the body of the cell disappears, and then the nucleus (Hlava). 

 The products of their dissolution are dissolved in the plasma, and one 

 of these products is fibrinoplastin. At the same time the fibrin-ferment 

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

 corpuscles. Fibrinoplastin 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 blood-plates (p. 21), 

 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 also a constituent of the 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 union of the three 

 substances will ensue. 



[It is worthy of remark to recall the conclusion arrived at by And. 

 Buchanan, viz., that the potential element of his "washed blood-clot" resided 

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

 that the buffy-coat of horse's blood, which is very rich in white corpuscles, 

 produced coagulation rapidly. Buchanan compared the action of his washed clot 

 to that of rennet in coagulating milk.] 



Pathological. Al. Schmidt and his pupils, Jakowicki and Birk, 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. Kohler). In febrile cases generally, the amount of 

 ferment is somewhat more abundant (Edelberg and Birk). After the injection 

 of ichor into the blood an enormous number of colourless corpuscles are dissolved 

 (F. Hoffmann). 



31. Relation of the Red Blood-Corpuscles to the 

 Formation of Fibrin. 



That the red blood-corpuscles may participate in the production of 

 fibrin is proved by many experiments. 



