34 COLLECTED STUDIES IN IMMUNITY. 



Though the existence of the antiautolysin is theoretically pos- 

 sible, we have thus far been unable to demonstrate it. To do this 

 it would first be necessary to get hold of an appropriate autolysin. 

 The possibility of getting this, however, is only conceivable in such 

 favorable cases where the autolysin might be produced critically 

 and in large amounts. This certainly did not occur in the cases 

 observed by us, and we were therefore compelled to try a different 

 method to demonstrate such an antibody. We know of a number 

 of haemolysins which dissolve goat-blood and which therefore fit 

 to certain haptophore groups of the goat blood cells. It is con- 

 ceivable that one of these haptophore groups is identical with that 

 of the autolysin sought for, and that an antiautolysin fits this 

 group. 1 



With this end in view we have made a number of experiments 

 and tested the action of our inactive goat serum on the goat-blood- 

 dissolving action of dog serum, pig serum, and goose serum ard on 

 the serum of a rabbit treated with goat blood. The results, however, 

 were not positive. From this, of course, we are not to conclude 

 that antiautolysins are not at all present in these cases. We shall 

 rather extend and vary our experiments in all possible directions 

 until a lucky coincidence leads us to find a fitting hsemolysin. 



Perhaps the most important of the questions thus presented is 

 whether this deficiency of binding groups in the red cells is performed, 

 or whether it is due to a new regulating power of the organism. In 

 the latter case this power would be suited in the highest degree to 

 protect the body even without the formation of an antiautolysin. 



In one case, to be sure (goat E), it seemed as though the insen- 

 sitiveness was developed only in response to the blood injection. 

 The blood-cells of this goat (the goat had been repeatedly injected) 

 were primarily sensitive to isolysins A and B. After the injection 

 there developed a complete insensitiveness to isolysin B, although 

 the sensitiveness to A remained. In this case an isolysin was not 

 developed, so that if accidental circumstances are excluded, it appears 

 as if under the influence of this blood injection a direct change or 

 destruction of the binding groups had taken place. 



We may perhaps also assume that the complete insensitiveness 



1 The multiplicity of the combining groups of the blood-cells is well illustrated 

 by the blood of buck A. This blood is insensitive to the isolysins mentioned. 

 Independently of this, however, it retains complete sensitiveness to hsemolysins 

 of a different origin, pig serum, goose serum, specific goose serum from rabbits. 



