CONTRIBUTIONS TO THE STUDY OF IMMUNITY 43 



from the serum. In this, therefore, the combining relations are 

 just the opposite of those found by Ehrlich and Morgenroth to exist 

 between blood-cells and their corresponding immune body. The 

 tracheal epithelial cells must therefore possess complementophile 

 groups. The immune bodies, which according to the side-chain theory 

 are only the side-chains thrust off into the circulation, are similarly 

 supplied with complementophile groups. These facts speak for 

 the correctness of the views of Ehrlich and Morgenroth, especially 

 when we consider that a cell, corresponding to its many-sided func- 

 tions, possesses not merely one kind of side-chain, but side-chains 

 of the most highly developed form. 



Mammalian erythrocytes in contrast to the tissue cells seem 

 not to possess complex side-chains; and this is readily understood 

 when we consider that the red blood-cells of these animals, being 

 without a nucleus and unable to maintain their nutrition independently 

 are not complete analogues of the tissue cells; and further that 

 their conditions of nutrition, corresponding to their simpler func- 

 tions, must be less complicated than those of the typical tissue cell. 

 Among the living constituents of the body, the red blood-cells con- 

 stitute the simplest case and are therefore particularly adapted to 

 the solution of many special problems in immunity, as can be seen 

 from the course of the last experiments. 



The phenomenon, that body cells are able to abstract complement 

 from the serum, furnishes us with a good explanation of the fact 

 that immune sera are often so little active in an organism of a dif- 

 ferent species. The immune body, which in stronger concentrations is 

 not saturated with complement, even when the immune serum is 

 perfectly fresh, can lose its complement entirely in the body of an 

 animal of different species ; it will therefore become active only when 

 it finds a fitting complement in the new organism. Hence in serum 

 therapy it is advisable, as Ehrlich has proposed, to employ for pur- 

 poses of immunization, animals closely related to man, and further- 

 more to search for anthropostable complements. 



B. Phagocytosis and Globulicidal Immunity. 



In a previous communication * I expressed the view that the specific 

 increase of the globulicidal function of the organism, following the 

 introduction of chicken and pigeon blood, is due to the action of the 



1 Miinch. med. Wochenschrift, 1899, Xos. 13 and 14. 



