THE PRECIPITINS AND THEIR ANTIBODIES 



and of casein. This duality of the processes recalls the 

 action of the compound haemolysins in which at first the 

 immune-body is absorbed in the erythrocytes, following 

 which the formation of haemolysin occurs. According to 

 Bordet's view, the parallelism between haemolysis and co- 

 agulation is still more prominent. 



Bordet and Gengou 1 suggest that the action of fluorides 

 on blood-plasma interferes not only with the action of the 

 Ca ions, which are precipitated from the solution as CaFl 2 , 

 but also with that of the fibrin-ferment, which is carried 

 down from the solution by the precipitate. The addition 

 of an oxalate does not interfere sensibly with the action 

 of the ferment. 



Leo Loeb 2 found a certain specificity between fibrin- 

 ferment and plasma, " in so far as the blood of each species 

 of animal used coagulated more rapidly under the influence 

 of the tissues of animals of the same species or of the 

 tissues of related animals than under the influence of the 

 tissues of more distant animals." The addition of serum of 

 the animal producing the fibrin-ferment increases the ac- 

 tion. Even the products of bacteria (especially Strepto- 

 coccus pyogenes aureus) are sometimes favourable to the 

 coagulation. 



There is a third type of coagulation provoked by a 

 ferment. In certain fruits and even roots of plants occurs 

 a substance called pectin. This substance gives with 

 water solutions of high viscosity; it is precipitated by 

 alcohol. It may be coagulated by means of a ferment called 



1 Bordet and Gengou: Ann. de VInst. Pasteur, 18. 98 (1904). 



2 Leo Loeb: Hofmeisters Beitrage, 5. 534 (1904) ; Journ. of Medical Re- 

 search, 10. 407 (1903). 



