FORM-ELEMENTS AND COAGULATION. 315 



are not necessary for the contraction of the clot nor for the coagulation 

 as a whole, and they are absent in the lymph and serous fluids. Accord- 

 ing to PETRONE 1 they indeed have a function in retarding coagulation. 



WOOLDRIDGE 2 takes a very peculiar position in regard to this question: he 

 considers the form-elements as only of secondary importance in coagulation. 

 As he has found, a peptone-plasma which has been freed from all form-con- 

 stituents by means of centrifugal force yields abundant fibrin when it is not 

 separated from a substance which precipitates on' cooling. This substance, 

 which WOOLDRIDGE has called A-fibrinogen, seems to all appearances to be a 

 nucleoproteid, which, according to the unanimous view of several investigators, 

 originates from the form-elements of the blood, either the blood-plates or the 

 leucocytes and the generally accepted view as to the great importance of the 

 form-elements in the coagulation of the blood is not really contrary to WOOL- 

 DRIDGE'S experiments. 



There is great diversity of opinion in regard to those bodies which 

 are eliminated from the form-elements of the blood before and during 

 coagulation. 



According to ALEX. SCHMIDT the leucocytes, like all cells, contain 

 two chief groups of constituents, one of which accelerates coagulation, 

 w r hile the other retards or hinders it. The first may be extracted from the 

 cells by alcohol, while the other cannot be extracted. Blood-plasma 

 contains only traces of thrombin, according to SCHMIDT, but does con- 

 tain its antecedent, prothrombin. The bodies which accelerate coagu- 

 lation are neither thrombin nor prothrombin, but they act in this wise 

 in that they split off thrombin from the prothrombin. On this account 

 they are called zymoplastic substances by ALEX. SCHMIDT. The nature 

 of these bodies is unknown, and SCHMIDT has given no opinion as to 

 their relation to the lime salts, which have been found to have zymoplastic 

 activity by other investigators. 



The constituents of the cells which hinder coagulation and which are insoluble 

 in alcohol-ether are compound proteins, and have been called cytoglobin and 

 preglobulin by SCHMIDT. The retarding action of these bodies may be sup- 

 pressed by the addition of zymoplastic substances, and the yield of fibrin on coagula- 

 tion in this case is much greater than in the absence of the compound protein 

 retarding coagulation. This last supplies the material from which the fibrin is 

 produced. The process is, according to SCHMIDT, as follows: The preglobulin 

 first splits, yielding serglobulin, then from this the fibrinogen is derived, and from 

 this latter the fibrin is produced. The object of the thrombin is two-fold. The 

 thrombin first splits the fibrinogen from the paraglobulin, and then converts the 



1 See footnote 2, p. 308. Also Schwalbe, liters, z. Blutgerinnung, etc., Braun- 

 schweig, 1900; Morawitz, Deutsch. Arch. f. klin. Med., 79, and Hofmeister's Beitrage, 

 4 and 5; Biirker, Pfliiger's Arch., 102, and Centralbl. f. Physiol., 21; Deetjen, 1. c.; 

 Le Sourd and Pagniez, Journ. de Physiol., 11; Vinci and Chistoni, Chem. Centralbl., 

 1909, 2, 838, and Maly's Jahresb., 39; Aynaud, Maly's Jahresb., 39; 165; Petrone, 

 Maly's Jahresber., 31, p. 170. 



2 Die Gerinnung des Blutes (published by M. v. Frey, Leipzig, 1891). 



