BACTERIOLYSINS AND HJLMOLYSINS 89 



auto-anticomplement, i.e., substances developed 

 within the organism against its own complements, 

 has not yet been demonstrated. Ehrlich and Mor- 

 genroth were able to excite the production of an 

 auto-anticomplement in a rabbit by treating the 

 animal in a certain way. Ordinarily, normal rab- 

 bit serum is slightly solvent for guinea-pig blood. 

 If the rabbits are treated with goat serum, the rab- 

 bit serum loses this solvent power for guinea-pig 

 red cells. Even if fresh, normal rabbit serum is 

 now added, haemolysis does not take place, although 

 we know that this fresh serum is haemolytic. This 

 shows that in the serum of the rabbit treated with 

 goat blood, an anticomplement has been formed 

 which combines with the complement of normal 

 rabbit blood, for it was able to inhibit the action 

 of the complement of the normal, freshly added 

 rabbit serum. In the rabbit's body, then, as a 

 result of this procedure, an anticomplement has 

 been formed against the complement of its own 

 serum, a true auto-anticomplement. 



Now, according to the side-chain theory, there 

 are no receptors in an organism for the complements 

 of the same organism. The formation of these 

 auto-anticomplements, according to Ehrlich, can 

 only be explained by assuming that in normal goat 

 serum there are present complements which are 

 almost identical with those of the rabbit serum, 

 but which differ from them in that they find recep- 



