BACTERIOLYSIS AND ALLIED PHENOMENA 149 



lytic to certain red corpuscles are so in virtue of containing 

 amboceptors with cytophile haptophore groups which fit the 

 receptors of these cells and complements which can dissolve 

 them. He was also able to show, by an ingenious experiment, 

 that when a normal serum can hgemolyze the corpuscles from 

 different species of animals, it does so by the action of different 

 amboceptors, and in some cases of different complements also. 

 We must imagine, therefore, that normal serum contains numerous 

 antibodies of the amboceptor type, and adapted to dissolve 

 numerous foreign substances when they gain access to the blood ; 

 and it seems reasonable to believe that these normal antibodies 

 and those which are formed as a result of the presence of the 

 foreign substances play a part of the greatest importance in 

 immunity. 



The question then arose, Do animals possess or form haemolysins 

 adapted to the solution of their own corpuscles in other words, 

 an auiohamolysin ? For instance, if a person sustains a large 

 internal haemorrhage, and the blood is absorbed, is he thereby 

 stimulated to the production of a substance which dissolves his 

 own red corpuscles ? Ehrlich pointed out that such a phenomenon 

 is unknown, and set out to investigate the reason of its non- 

 occurrence. He selected goats as his experimental animals, and 

 injected into them large amounts of mixed blood-corpuscles from 

 other goats. In a week's time the serum was found to be power- 

 fully haemolytic, but only towards the corpuscles of other goats, 

 never towards its own; thus the serum of the first animal 

 experimented on was found to dissolve the corpuscles of goats i, 

 2 > 4> 5> 6, and 9 easily; those of 3 and 8 less powerfully; and 

 those of 7 and of itself not at all. A second animal was treated 

 just like the first, and it also developed a hgemolysin, but this 

 did not act on its own corpuscles, nor on those of other goats 

 in the same way as that of the first ; evidently a different series 

 of amboceptors had been formed. Ehrlich speaks of a hgemolysin 

 formed by the injection of the corpuscles of a different species 

 as heterolysin, that which acts on the blood of the same species 

 as an isolysin ; one which would act on the blood-corpuscles of 

 the same animal would be called an autolysin, but this is never 

 formed. 



In attempting to discover the reason for this non-formation 

 Ehrlich first proved that the amboceptor of the isolysin was 

 anchored by the corpuscles which it dissolved, but not by those 



