334 MATSUZIRO TAKENOUCHI 



c. Test of the antirat blood rabbit serum in vivo 



As a test of this antirat corpuscle rabbit serum in vivo, we 

 injected a relatively large amount of this serum (0.5 cc, 1.0 cc, 

 and 1.5 cc.) into three rats weighing 30 to 34 grams (thirty-five 

 days of age), but observed no pathological symptoms after the 

 injection nor any deviation of the growth curve as compared with 

 the control animals. Fourteen days after the serum injection, all 

 the animals were killed and examined. They were found to be 

 normal. 



From these experiments it appears that the hemolysin produc- 

 tion in rabbits by the injection of washed rat corpuscles is, if not' 

 entirely negative, very faint. The normal guinea-pig serum can 

 be used as complement with the antirat corpuscles hemolysin 

 obtained from the rabbit, while the normal rat serum is quite 

 incapable of activating the hemolysin, since it contains a sub- 

 stance or substances which protect the red cells in some way or 

 other from solution by the hemolysin. 



This is apparently but another case of the well-known fact that 

 the fresh blood sera of various species differ from each other 

 considerably in their power to activate the bactericidal or hemo- 

 lytic amboceptor. In regard to hemolysis, fresh guinea-pig 

 serum is very powerful in activating many sensitized cell com- 

 plexes, but weak in activating sensitized guinea-pig corpuscles. 

 Often we find that the alexin (complement) of an animal is en- 

 tirely impotent or but slightly capable of producing hemolysis 

 of the sensitized cells of its own species, though this is not a 

 general rule (Zinsser, '18, p. 154). The rat complement is entirely 

 impotent in producing hemolysis of the sensitized rat corpuscles, 

 and this seems to result from the presence of some substance or 

 substances in the normal rat serum, which, in some way or other, 

 perfectly protect the rat corpuscles from hemolysis. 



