THE COAGULATION OF THE BLOOD. 375 



similar observations, formulated a new and eminently simple 

 theory of blood coagulation, which was almost immediately 

 annihilated. 



The next to enter the field were Arthus and Pages, who 

 made the brilliant discovery that the blood may be kept 

 liquid by decalcification. This may be readily brought 

 about by mixing the blood immediately it is shed with a 

 0*2 per cent, solution of potassium oxalate. They consider 

 that fibrin is a calcium compound of fibrinogen, and their 

 experiments further led them to believe that the ferment as 

 well as the calcium salt is necessary for the transformation 

 of fibrinogen into fibrin. 



Green, in the work already alluded to, took up the 

 question whether the fibrin-ferment exists in the blood as 

 a zymogen (mother of ferment) which is changed into the 

 ferment by the calcium salt. His conclusions, however, 

 were negative. This point was taken up by Pekelharing, 

 who prepared from various forms of extravascular plasma a 

 substance with the solubilities of a globulin which possesses 

 no fibrinoplastic properties, but which, by treatment with a 

 calcium salt, assumes the fibrinoplastic activities of fibrin- 

 ferment. 



He therefore regards it as the mother substance of the 

 ferment, and as identical with a substance I myself had 

 previously described as cell-globulin. Pekelharing considers 

 with Arthus and Pages that fibrin is a calcium compound 

 of fibrinogen, and that the main action of the ferment is the 

 handing over of the calcium to the fibrinogen. Oxalates 

 hinder coagulation because they precipitate the necessary 

 calcium salts ; and there is very good reason for believing 

 that peptone acts in a similar way for a similar reason, 

 namely, its affinity for calcium salts. 



He then proceeded to examine the "tissue fibrinogens," 

 the substances which Wooldridge discovered to be capable 

 of producing intravascular coagulation. Like other ob- 

 servers he found their chief constituent to be nucleo- 

 albumin ; and in a later research he discovered that the 

 globulin just alluded to, my cell-globulin, was also a sub- 

 stance of the same nature, yielding an insoluble residue of 



