70 GENERAL AND PHYSICO-CHEMICAL. 



If, therefore, an antigen of the corresponding immune serum be heated 

 to 56 (amboceptor) and mixed with sufficient amount of normal serum 

 (complement), then the complement is bound up so that when subsequently 

 serum-free red-blood corpuscles and a certain quantity of immune serum, 

 obtained by immunization with these and after losing its complement 

 by heating to 56, are added, no solution of the red-blood corpuscles 

 (haemolysis) takes place. If in the first mixture either the antigen or the 

 corresponding amboceptors are absent then the complement is not 

 combined and a haemolysis occurs because the complement cannot unite 

 with the haemolytic amboceptors added. In this manner it has been 

 attempted to determine the presence of an antigen or of amboceptors 

 which fit with the antigen (method of complement deviation). 



The protective substances formed by immunization can protect the 

 organism against many fatal doses of the antigen and this protective 

 power can be brought about by the parenteral introduction of the immune 

 serum of another organism. The immunity is called active when the 

 organism obtains the antigen and itself produces the corresponding 

 protective substance. On the contrary the immunity is called passive 

 if the organism receives the anti-body formed in another living being 

 by active immunization. 



During immunization under certain circumstances it is observed 

 that a condition of super-sensitiveness toward the antigen exists. This 

 super-sensitiveness occurs only toward the antigen used and is therefore 

 specific. The same has been observed in using the soluble as well as the 

 formed antigens. This mysterious phenomenon has been called anaphyl- 

 axis. 



V. IONS AND SALT ACTION. 



We have previously mentioned various processes which depend upon 

 the influence of ions. To these belong the precipitation of suspension 

 colloids by electrolytes as well as different catalytic processes. That 

 in the last case we are dealing with the action of ions is proven by the 

 fact that the velocity coefficient is proportional to the concentration 

 of a certain kind of ion. Nevertheless it has been shown, that the 

 velocity coefficient in the inversion of cane-sugar, by acid, is only propor- 

 tional to the H ions when dilute acids are used. With greater concen- 

 tration disturbances occur which can be ascribed to the action of the 

 negative ions of the acids. The catalytic processes can be influenced 

 by salts in a similar manner (salt action). 



The enzyme action has shown itself proportional to the quantity of enzyme 

 in certain cases. EULER l has attempted to show a correspondence between ion- 



^eitschr. f. physik. Chem., 36, 641 (1901). 



