PLURALITY OF COMPLEMENTS OF THE SERUM. 



199 



When the papain was allowed to act longer, the resistant com- 

 plement III was also affected, so that usually after one and one-half to 

 two hours digestion, the goat serum was entirely deprived of all its 

 complements. 



Treatment with alkali in place of papain digestion gave analogous 

 results. We made use of soda and proceeded as follows: 10 cc. 

 goat serum to w" ich 1 cc. 7% soda solution had been added, were 

 kept in the incubator for one and one-quarter hours, and then neutral- 

 ized with hydrochloric acid. The solvent power was compared with 

 a goat serum which by the simultaneous addition of soda and hydro- 

 chloric acid, had been brought to the same concentration of salt 

 without having been subjected to the damaging influence of the 

 soda. 1 (See Table II.) 



TABLE II. 

 DESTRUCTION OF THE GOAT SERUM BY MEAXS OP SODA. 



Hence, owing to the action of the soda the complements for Cases I, 

 II, IV, and V have completely disappeared, whereas Complement III 

 is still present, although its action is but one-fourth of what it was. 



We have furthermore effected a separation of the complements by 

 heating the goat serum to 49-50 C. for half an hour. At this tempera- 

 ture the solvent action of normal goat serum for rabbit and guinea- 

 pig blood has been completely destroyed or almost so. On the other 

 hand, the complement action for the artificially produced immune 

 bodies is more or less preserved, as can be seen from Table III. 



The experiment shows that in this case complement IV is the 

 most resistant, in contrast to its behavior with papain or soda. In 

 the two latter cases, complement III had shown itself the most resist- 

 ant. If we examine the table more closely we shall further see a 



1 The resulting salt concentration, by the way, is so slight that the solvent 

 power was in no way decreased thereby. 



