54 IMMUNE SERA 



The Exciting Agent. If we now seek to discover 

 the constituent part of the red cell which in the 

 treatment excites in the animal body the production 

 of the specific haemolysin, we find this to be, accord- 

 ing to Bordet and v. Dungern, the stroma of the red 

 cells. This separated from the cell contents and 

 injected into animals will likewise excite the produc- 

 tion of specific haemolytic serum. In opposition 

 to this, Nolf assumes that the stroma excites the 

 production of the above-mentioned agglutinins, and 

 that the production of the substance sensibilatrice 

 is called forth by the contents of the red cells. 



Resume. Reviewing the important facts we have 

 learned, we find them to be as follows: By means 

 of the treatment of one species of animal with the 

 red cells of a different one, the serum of the first 

 species acquires an uncommonly increased power 

 to dissolve and to agglutinate the red cells of the 

 second species. This increased hasmolytic power 

 shows itself not only in vivo, so that an animal 

 so treated is able to cause red cells injected into 

 it to rapidly dissolve and disappear, but it shows 

 itself also in vitro when the serum of this animal 

 is used. The process consists in the combined 

 action of two substances, that which is excited 

 in response to the injection, the substance sensi- 

 bilatrice, and the alexin of normal serum. 



Analogy between the Bacteriolytic and Haemoly- 

 tic Processes. If we now recall the main points in 



