334 COLLECTED STUDIES IN IMMUNITY. 



serum, which had thus been deprived of much of its toxic property, 

 would appear to be preferable, for, owing to the complementoids 

 which it contains, this would cause the production of anticomplements 

 just as well as fresh serum. (See pages 79 et seq.) 



If it is desired by the injection of a certain serum to produce 

 anticomplements which are also directed against various other sera, 1 

 it is necessary to repeat the injections several times in increasing 

 amounts. While treating a goat with rabbit serum, Ehrlich and 

 Morgenroth observed the development first of anticomplements 

 directed exclusively against the complement of rabbit' serum (iso- 

 genic anticomplements); in course of time anticomplements directed 

 against the complements of guinea-pig serum (alloiogenic anticom- 

 plements) also appeared. Here evidently we are dealing with partial 

 complements, present in rabbit serum in small amounts, which require 

 several repetitions of the injections in increasing amounts in order 

 to excite the production of anticomplements. 



In the production of serum coagulins [precipitins] one proceeds as 

 for anticomplements. These serum coagulins have been shown to 

 possess considerable value for the forensic determination of various 

 species of blood, especially human blood, as has been shown by the 

 researches of Wassermann and Schiitze, Uhlenhuth, and many others. 

 In the preduction of milk coagulins one or two injections of 20 to 

 40 cc. of milk into a rabbit are usually sufficient. The milk can be 

 heated to 60 previous to injection in order to reduce the number of 

 germs present. In connection with the production of serum coagu- 

 lins Uhlenhuth makes some interesting statements (Deutsch. med. 

 Wochenschr. 1902, No. 37). Among other things he describes 

 something we had also noticed, namely, the occasional failure of the 

 reaction and the development of "alloiogenic " coagulins as the 

 titer of the serum increased, a fact which corresponds to what we 

 have above described for the formation anticomplements. 2 



IV. Determining the Haemolytic Action. 



The fact that certain poisons of vegetable or animal origin, as 

 well as normal sera and other body fluids, possess a haemolytic action 

 can be determined so readily that it will be superfluous to enter further 



1 See pages 111 et seq. 



2 Concerning isogenic and alloiogenic anticomplements, see Morgenroth 

 and Sachs, pages 258 et seq. 



