REACTIONS BETWEEN ANTIBODIES 19 



The experiments of Calmette yield therefore no evidence 

 for his conclusion that the binding of snake-venom by 

 antivenin is a reversible process, whereby as soon as the 

 free antivenin is destroyed, its compound with the poison 

 is dissociated with the production of new quantities of 

 poison and antivenin. The same comment may be made 

 regarding the decomposition, by boiling, of the innocuous 

 mixture of a poison generated by the Bacillus pyocyaneus 

 and its antitoxin. After the boiling, the poison, which is 

 stable at that temperature, remains in the solution, while 

 the more unstable antitoxin is destroyed, as Wassermann * 

 has shown. 



But there are many other cases that demonstrate rever- 

 sible processes between analogous substances against which 

 no such objections can be upheld. One of the most 

 remarkable of these processes is used for the production 

 of the so-called immune bodies. (Ehrlich terms them 

 "amboceptors.") If we inject a suspension of the ery- 

 throcytes of an ox into the vein of a rabbit, this animal 

 after a certain time presents in its blood a hasmolytic 

 substance, which haemolyses the erythrocytes of the blood 

 employed; i.e. erythrocytes of the ox and perhaps of some 

 nearly related species. 



If we heat blood-serum containing this haemolysin to 

 55 C. for about thirty minutes, we find that it loses its 

 haemolytic power. It is said to be "inactivated." The 

 hsemolysin is evidently decomposed, but a fraction of it 

 remains intact, as may be shown by adding the normal 

 serum of a guinea-pig. After the addition of this in- 



1 Wassermann : Zeitschr. f. Hygiene u. Infedionskrankhtiten, 22. 263 

 (1896). 



