40 COLLECTED STUDIES IN IMMUNITY. 



result is easily understood on the basis of the side-chain theory, 

 if we assume that the production of the complement is entirely inde- 

 pendent of the binding of the injected substances by the side-chains, 

 and is probably referable to other cells. If the production and 

 thrusting off of the particular side-chains exceeds a certain limit, these 

 side-chains will fail to find in the blood serum any more complement 

 whose haptophore group is still available. The disproportion between 

 immune body and complement then sets in. This will be most 

 marked in those cases in which the normal serum contains but little 

 complement and in which a considerable production of immune body 

 can be effected. 



2. Certain experiments which I have described in a previous com- 

 munication regarding globulicidal action of the animal organism 1 led 

 me to the view that the immune body combines with a particular 

 group of the blood-cells and thus leads to their solution. This con- 

 ception was based on the fact that a specific affinity exists between 

 erythrocyte and the corresponding immune body, which affinity must 

 be the same in the production as in the action of the immune body. 

 According to the side-chain theory just this affinity is the driving 

 force which on the one hand anchors the corresponding group of 

 the erythrocyte to the preformed side-chains (such side-chains when 

 thrust off constituting the immune body), and on the other, in 

 haemolysis, anchors the immune body, and with it the complement, 

 to the blood-cells. 



It must always be conceded to the opponents of this view that the 

 evidence to prove such complicated processes as will develop in the 

 cells after inoculations of blood into an animal body will not, perhaps, 

 be absolutely conclusive. If one were willing to forego an explana- 

 tion of the specificity, one could assume that the immunity reaction 

 is based on an increase of the normal function of certain cells whose 

 products are formed without requiring a certain group to fit into a 

 corresponding one. 



It was therefore of great interest to be able to show experimentally 

 that the group which in haemolysis combines with the immune body 

 actually gives rise to the production of the immune body. This 

 demonstration was effected by injecting blood together with inac- 

 tivated blood immune serum. 



If the development of the antibody is independent of the group 



4 Munch, med. Wochenschrift, 1899, Nos. 13 and 14. 



