REACTIONS BETWEEN ANTIBODIES 21 



acts therefore not as a sensibilitator, but is chemically 

 bound, as Ehrlich insists. This is certainly true for the 

 alexin and " immune-body" absorbed by the erythrocytes; 

 but the phenomenon of Neisser and Wechsberg indicates 

 that these two substances are combined to a certain degree 

 even outside the erythrocytes (compare Chapter VIII). 



Here we have evidently before us a reversible chemical 

 process. Similar reversible processes are found for all 

 the different haemolysins which are formed after the in- 

 jection of a suspension of erythrocytes from one animal 

 into the veins of an animal of another species. In a similar 

 manner, according to Ehrlich, behave the bacteriolysins, 

 which are formed analogously to the haemolysins. A 

 similar experiment was made by Madsen, Famulener, and 

 Walbum on innocuous mixtures of the haemolytic agent 

 produced by staphylococcus, called staphylolysin, and its 

 antitoxin. Here the innocuousness of the mixture shows 

 that the haemolysin is really bound, for during the time of 

 the reaction, as long as there is some haemolysin free, it is, 

 on being mixed with a suspension of erythrocytes, rapidly 

 absorbed by these, which thereafter lose their haemoglobin. 

 The staphylolysin behaves in a very peculiar manner. If 

 it is heated to 70 C, it loses a great deal of its haemolytic 

 power, which, curiously enough, returns almost completely 

 after heating for five minutes to 100 C. Its antitoxin is 

 destroyed by such a heating. On heating the innocuous 

 mixture of staphylolysin and its antitoxin for five minutes 

 to 100 C., the mixture gains haemolytic properties. The 

 binding of staphylolysin with its antitoxin is therefore a 

 reversible chemical process. 



Bordet injected the milk of one animal into another 



