46 PROPERTIES OF HJSMOLYTIC SERA 



ON COMPLEMENTOIDS AND THEIE COMBINATION 



Ehrlich has pointed out the analogy which exists between 

 complements and toxins of various kinds. Looked at from 

 the point of view of the red corpuscle or bacterium, the 

 complement is the toxic agent which leads to its partial or 

 complete destruction, the auxiliary action of the immune- 

 body being, however, necessary. From his study of changes 

 which occur in toxins and their neutralization by anti-toxin, 

 he came to the conclusion that the toxophore group might 

 undergo degeneration while the haptophore group survived, 

 though its combining energy might be weakened. To such 

 an altered toxin he gave the name toxoid. The results of 

 hsemolytic studies led him to the conclusion that a similar 

 change might occur in complements, the result being com- 

 plementoids. The chief evidence for the existence of com- 

 plementoids is the following : 



In most cases when normal sera are heated to 55 C. for 

 an hour, the characteristic action (haemolysis, bacteriolysis) 

 of complement is lost, but such a serum when injected into 

 an animal of different species has the faculty of leading to 

 the formation of anti-complement. Hence, apparently the 

 zymotoxic group of the complement has been destroyed, 

 while the haptophore remains. (As mentioned above (p. 40) 

 this argument has now lost its validity, since it has been 

 shown that receptors in the serum injected give rise to anti- 

 substances and the combination of these two absorbs or fixes 

 complement (vide also p. 133).) Again, Ehrlich and Sachs l 

 showed in the case of the haemolytic action which the dog's 

 serum normally possesses towards the guinea-pig's cor- 

 puscles, that the combining groups of sensitized corpuscles 

 might be filled up by complementoid on treating with heated 

 serum, and thus the action of complement, i. e. haemolysis, 

 might be prevented. In most instances, however, this is 

 1 Ehrlich and Sachs, Berlin. Klin. Woch., 1902, No. 21. 



