STUDIES OX HAEMOLYSIS. 33 



(immune body) reach the tissues. This would effect a production 

 and thrusting-off of the corresponding group a, which would then 

 circulate as an antiautolysin and serve to switch the autolysin there- 

 after formed, away from the blood-cells. Be this as it may, whether 

 the organism be injured as a result of an acute flooding with the 

 liberated receptors, or whether this injury be prevented by the slow 

 course of the reaction, the end result in the second case will regularly 

 be a development of an antiautolysin. 1 



The three possibilities, therefore, which present themselves on 

 the injection of blood of the same species are: 1, the failure of any 

 formation of hcemolysin; 2, the formation of an isolysin; 3, the develop- 

 ment of an antiautolysin. 



Each haptophore group of the red blood-cells (and we have reason 

 to assume a large number of different groups in each erythrocyte 

 of every species) will have to react, in the animal body, according 

 to the above scheme. This leads to a large number of possibilities. 

 If, for example, an injected blood-cell possesses three haptophore 

 groups, a, /?, 7-, it will be possible for a to cause the development of 

 an isolysin, /? an antiautolysin, while ? produces no effect whatever. 



This, of course, complicates the problem extraordinarily. A 

 multiplicity of variations is presented whose complete investigation 

 would require a great deal of time and labor. The three cases above- 

 mentioned, however, amply suffice to explain all our observations 

 thus far. The differences in the three isolysins previously described 

 are to be ascribed to the action of three different haptophore groups 

 of the blood-cells; and the fact that the same blood injected into two 

 animals causes the development of different isolysins is to be explained 

 by the individual differences in the receptors. Finally, the failure 

 of any isolysin reaction whatever would correspond to an absence 

 of suitable receptors. 



1 The cases here discussed are of general significance for the question whether 

 hsemolysins exist at all, and they determine also the conditions under which 

 the hspmolysins of normal serum are capable of existence (see also the second 

 communication, pages 11-23). The fact that a normal haemolysin dissolves the 

 blood-cells of foreign species but spares its own blood-cells, that, for example, 

 dog serum dissolves guinea-pig blood, rat blood, goat blood, sheep blood, etc., 

 but not dog blood, is only a single instance of the above-mentioned general 

 law that autolysins are not capable of existence in an organism; for the presence 

 of receptors, which is essential to the production of autolysins, would, if the 

 autolysins should develop, soon result in a compensation by means of anti- 

 autolvsin formation. 



