FURTHER DEVELOPMENT OF KNOWLEDGE 189 



analogous to the sensitizers described by Bordet in bacteriolytic and 

 hemolytic sera, and later found in the majority of antimicrobial 

 sera." The important point in this interpretation is that Gengou 

 conceived the existence of antiprotein sensitizers, in addition to the 

 precipitins, formed as a response to immunization with amorphous 

 protein. Moreschi 78 soon confirmed Gengou' s experimental deter- 

 minations, and Neisser and Sachs 79 took the further logical step of 

 applying this knowledge to the determination of proteins for foren- 

 sic purposes. This, too, we will further discuss when we speak of 

 the practical features of these phenomena. It thus appears that the 

 fixation of alexin is a generalized property of all mixtures in which 

 an antigen is brought into contact with its specific antibody, whether 

 the antigen is in the form of the whole bacterial or other cell, or in 

 that of a dissolved protein, animal serum, or egg-white, etc. 



The observation of Gengou, though for a time insufficiently val- 

 ued, has had a profound influence upon the subsequent under- 

 standing of serum reactions. The fundamental importance of 

 this work was not fully recognized until his studies had found 

 logical continuation in the investigations of Gay 80 and in those of 

 Moreschi. 



Moreschi 81 studied the antihemolytic properties possessed by the 

 serum of a rabbit which had been treated with normal goat serum. 

 He found that such a serum had distinct anticomplementary powers 

 when it was added to a hemolytic system of ox blood sensitizer (ob- 

 tained against ox blood from rabbits), and goat complement.. With 

 such a hemolytic system, however, there was anticomplementary ac- 

 tion only against goat complement and not against rabbit or guinea 

 pig complement. If, however, he used a hemolytic system in which 

 the amboceptor or hemolytic sensitizer employed was one obtained 

 from a goat, the serum was anticomplementary for all complements 

 which were used. Moreschi concluded from this that the apparent 

 anticomplementary action of the serum could not be interpreted as 

 the action of a specific anticomplement in the sense of Ehrlich, but 

 that it resulted from the reaction which took place as the consequence 

 of union of the antibody in the anti-goat rabbit serum and goat pro- 

 tein, which was introduced into the tubes, in the first case with the 

 complement, and in the second with the amboceptor. He proved his 

 contention by obtaining similar universal anticomplementary action 

 when he added a little normal goat serum to the tubes set up as above 

 described. It is plain, therefore, that anticomplementary action can 

 be explained in observed cases by the simple consideration of the phe- 

 nomenon of Gengou. Similar findings were later recorded by Muir 



78 Moreschi. Berl. kl Woch., No. 37, 1905. 



79 Neisser and Sachs. Berl kl. Woch., No. 44, 1905. 



80 Gay. Centralbl. f. Bakt. I Orig. Vol. 93, 1905, p. 603. 



pl Moreschi. Berl kl Woch., 1905, No. 37, ibid., No. 4, 1906. 



