110 COLLECTED STUDIES IN IMMUNITY. 



animals with ox blood-cells are not, as a matter of fact, of simple 

 [einheitlich] nature. Those obtained from goats and geese are very 

 markedly, if not entirely, different from those of rabbits, while those 

 from guinea-pigs, rats, and dogs are partly so. 



We have already pointed out the significance of this circumstance 

 in II, page 92. In all probability similar conditions obtain for 

 bacteria, and it would therefore be advisable not to attempt the pro- 

 duction of bactericidal sera from a single animal species, as is now 

 customary, but to make a preparation containing a mixture of immune 

 sera derived from animals whose receptor apparatus are as divergent 

 as possible. 



III. Concerning the Variety of the Complementophile Groups of 

 Homologous Immune Bodies. 1 



From the foregoing sections it will be seen that in combating 

 infectious diseases we believe it advisable to employ simultaneously 

 a great many bactericidal immune bodies which, in conformity with 

 the multiplicity of groups in the bacterial cell, will differ in their 

 cytophile group. It will now be necessary to investigate the question 

 of a difference in the complementophile groups of these immune 

 bodies. However, the treatment of this question can at present only 

 be fragmentary, since our methods in this field are still very incomplete 

 and definite results can only be obtained in specially favorable cases. 



It will be advisable to commence this study with the immune 

 serum of a rabbit treated with ox blood. In this it has already 

 been pointed out that two portions of immune bodies are present, 

 each of which again is to be regarded as composed of a number of 

 partial-immune bodies.^ This view of the composition of the im- 

 mune bodies is supported by the reactivating experiments in ^-hich 

 a number of different kinds of sera furnished the complements. This 

 brings us to our present topic. 



We have already mentioned that the most favorable results are 

 achieved when our immune body is activated by rabbit or guinea- 

 pig serum; the activation by means of goat serum, together with its 

 peculiarities, has also been discussed at length. 



The following list of complements shows their action in the pres- 

 ence of varying amounts of an immune body from a rabbit immunized 

 with ox blood. The amount of complement employed was always ample. 



1 See also Ehrlich's later views, page 560. 



