340 MATSUZIRO TAKENOUCHI 



say, the normal rat serum with its complement cannot activate 

 the hemolysin against the rat corpuscles. The rat serum, even 

 after inactivation, possesses some substance which inhibits the 

 hemolysis. This substance may be some kind of anticomple- 

 ment or of anti-amboceptor, or a combination of both of these. 



6. The chicken is not suitable for the production of the he- 

 molysin acting upon rat corpuscles with either normal guinea-pig 

 complement or with normal rat serum as complement. Normal 

 rat complement cannot activate (complement) the hemolysin 

 from chicken against rat corpuscles, if anything like that sub- 

 stance is produced by the injection of rat corpuscles. 



7. It seems very likely that our attempt to produce strong 

 antithymus serum from the rabbit by the injection of rat thymus 

 and to make some studies on its action have failed, partly be- 

 cause the antibody production in the rabbit after the injection of 

 antigen which is obtained from the albino rat is not so active as 

 we anticipated it would be and partly because the thymus cells of 

 the rat are so protected from the cytolytic action of the injected 

 antithymus serum, that the normal complement or rat serum is 

 unable to activate the antibodies fully. The last statement is 

 based on the analogy with the hemolysin produced in the rabbit 

 by the injection of rat corpuscles, though the argument by 

 analogy is admittedly dangerous. 



8. From the above point of view, the publications of Shimizu, 

 Ritchie, and of Guyer and Smith have been discussed, and I 

 consider that their conclusion ought to have some more definite 

 proof from the serological side. We cannot yet admit that any 

 endocrine function of the thymus gland, either in the cortical or 

 the medullary portion, or in both, can play the principal role in 

 the physiological function of the thymus gland. 



