STUDIES ON H.EMOLYSINS. 117 



This brief analysis will show us that the complementophile groups 

 of the immune bodies do not in general possess the great importance 

 which we must ascribe to the cytophile groups. In order to obtain 

 the greatest therapeutic effect from the immune bodies, their com- 

 plementophile groups and the provision of suitable complements 

 cannot, of course, be neglected. In this connection Donitz (Klin. 

 Jahrbuch, 1897) first pointed out the importance, in the therapy of 

 infectious diseases, of finding sufficient sources of complements. 

 The conditions determining this have been more closely defined by 

 Ehrlich in his Croonian Lecture 1 of March 22, 1900, as can be seen 

 from the following extract: 



"Dr. Neisser at the Steglitz Institute sought to find an explana- 

 tion of Sobernheim's experiments. He was able to determine that 

 anthrax serum failed in mice even if large quantities of fresh sheep- 

 serum (i.e., containing an excess of 'complement') were introduced 

 at the same time. The failure in this case appears to be due, on 

 the one hand, to the destruction, in the body of the mouse, of the 

 'complement' present in the sheep serum, and, on the other hand, 

 to the fact that the 'immune body' yielded by the sheep does not 

 find in the mouse an appropriate new 'complement.' 



"From this it appears that in the therapeutic application of 

 antibacterial sera to man, therapeutic success is only to be attained 

 if we use either a bacteriolysin with a ' complement ' which is stable 

 in man (homostabile complement), or at least a bacteriolysin the 

 immune body of which finds in human serum an appropriate 'com- 

 plement.' The latter condition will be the more readily fulfilled 

 the nearer the species employed in the immunization process is to 

 man. Perhaps the failure which has as yet attended the employ- 

 ment of typhoid and cholera serum will be converted into success 

 if the serum be derived from apes and not taken from species so 

 distantly removed from man as the horse, goat, or dog. However 

 this may be, the question of the provision of the appropriate 'com- 

 plement' will come more and more into the foreground, for it really 

 represents the center round which the practical advancement of 

 the bacterial immunity must turn." 



In view of the fact that every normal serum contains a great 

 many complements, of which a larger or smaller part fits the most 

 varied immune bodies, the need of artificially supplying complements 



1 Proceedings of the Royal Society, Vol. 66. 



