ANTI-H^EMOLYSINS 455 



rabbit's serum can haemolyse, to a certain extent, the erythrocytes 

 of a guinea-pig. If goat's serum be injected into the rabbit, 

 however, the serum of the latter loses its haemolysing action on 

 the erythrocytes of the guinea-pig ; and even if some normal 

 rabbit's serum be added to the mixture, no haemolysis will occur. 

 To explain the production of anti-complement, we must suppose 

 the complements of the goat and rabbit to be very much alike, 

 but in so far different that the former find, in the tissue cells of the 

 latter, receptors with which their haptophoric groups unite, and 

 these receptors, being rendered useless to the tissue cell, become 

 regenerated in over excess and float free in the blood. The 

 complement normally present in the blood cannot, of course, unite 

 with receptors in the same animal's tissues, unless some other 

 body e.g. a foreign erythrocyte or a bacterium be present to 

 combine with the cytophilic group of the amboceptors. Nor 

 could the injection of complements very unlike those normally 

 present in blood lead to the production of anti-complements ; 

 because their haptophoric groups would not fit complemento-philic 

 endings. 



Anti-complements, then, are nothing more or less than free 

 receptors, and, as we might expect, these receptors can be dis- 

 connected from their cells by other means than the injection of 

 complements like them. Thus they can be liberated when the cell 

 is disintegrated, as in phosphorus poisoning. For example, the 

 serum of a rabbit, two days after receiving a poisonous dose of 

 phosphorus, could not produce any haemolysis of guinea-pig's 

 erythrocytes (Ehrlich and Morgenroth). 



Chronic suppuration may lead to the production of anti- 

 complement from the same cause. Even emulsions of fresh organs 

 can bind a certain amount of complement. As would be expected, 

 the presence of anti-complement materially lowers the natural 

 resistance of serum towards injections (Wassermarm 7 ). 



According to the side-chain theory, any substance containing 

 amboceptors which fit on to one or more of the receptors of an 

 erythrocyte will be capable of producing haemolysis, provided that 

 the other combining group of the amboceptors is united with a 

 complement or complements. As a matter of fact, there are a 

 number of substances, some of vegetable and some of animal 

 origin, which, when added to a suspension of erythrocytes in 

 isotonic saline, can cause haemolysis. The more important of these, 



