234 



COLLECTED STUDIES IN IMMUNITY. 



contradiction to our experimental results, let us examine his evidence 

 somewhat more closely. 



In support of his first assertion, that " the amboceptor of the 

 normal sera seems never to make the erythrocytes of another species 

 sensitive to their own serum," he advances the following eight com- 

 binations (see Table I) : 



TABLE I. 



It seems entirely to have escaped Gruber that only a few 

 lines previously he denies the existence of amboceptor in the first 

 three of these combinations. Hence he should not have included 

 these as evidences of the amboceptor's non-activatibility. for his 

 own experiments had shown him that in these ha?molysins no ambo- 

 ceptors could have been present. 1 From our own experiments we 

 know that the next three combinations (4-6) usually lead to solution 

 of the blood; there remain therefore only two cases (7 and 8) which 

 we may consider as evidence of Gruber's contention. 2 Against these 

 two cases can be placed a single case described by Gruber, one which 

 he advances to support his second statement, "that the specific 

 amboceptors make the erythro ytes soluble in their own serum." 

 Gruber believes he can say in advance that this is regularly the case. 



1 Since then, however, amboceptors have also been demonstrated in these 

 cases. (See H. Sachs, page 181.) 



2 One of these cases deals with the combination guinea-pig blood + chicken 

 serum. From Ehrlich and Morgenroth's earlier communications (see pages 88 

 et seq.) Gruber could have seen that between animal species so far removed 

 as chicken and guinea-pig the chances of complementibility are not as great 

 as they are between mammalian species. If Gruber therefore employs as evi- 

 dence such distantly related species he must necessarily also have used widely 

 separated species when complementing the immune sera. We have no doubt 

 at all that by immunizing distantly related species (birds) with guinea-pig 

 blood, amboceptors can be obtained which are not complemented by guinea- 

 pig serum, or at least not regularly so. 



