ENDOCRINE FUNCTION OF THE THYMUS GLAND 339 



maniculatus gambeli (Guyer and Smith) really could activate in 

 vivo the amboceptor which is obtained from duck or chicken 

 by the injection of guinea-pig thymus (Ritchie) or lens of rabbit 

 or Peromyscus (Guyer and Smith) and cause a cytolysis in a 

 true sense of the word. 



8. RESUME AND CONCLUSIONS 



1. The serum obtained from rabbits immunized with the thy- 

 mus substance of the albino rat shows some positive precipitin 

 reaction with the thymus extract — a reaction much stronger than 

 that from the normal rabbit serum. The specificity is, however, 

 not strictly limited, because the testis extract shows, though 

 slightly, a positive precipitin reaction with the antithymus 

 serum, while kidney and spleen extracts give a little lower degree 

 of positive reaction. Brain extract, however, does not produce 

 any precipitation with the antithymus serum. 



2. The antithymus rabbit serum does not show any positive 

 hemolytic action against rat corpuscles when guinea-pig normal 

 complement or rat normal serum is used as complement. 



3. The antithymus sera do not cause, when injected into rats, 

 any toxic symptoms which correspond to those of the ^primary 

 anaphylaxis.' The injected rats do not show any marked differ- 

 ence in their growth from control animals. None of the organs 

 of the injected rats show any macroscopical and microscopical 

 alteration which might be due to the antithymus serum injection. 



4. Nearly the same results were observed with the antitestis 

 serum from rabbits injected with the rat testis emulsion. The 

 precipitin reaction of this serum is not so strictly specific for 

 the testis extract. Tliis serum has no hemolytic action against 

 rat corpuscles. All rats injected wdth this serum grow very well, 

 and the testes of injected rats do not show any definite alteration 

 caused by the antitestis serum injection. 



5. Hemolysin production in rabbits by the injection of washed 

 rat blood corpuscles was attempted. The hemolysin produced in 

 rabbits shows a very weak positive hemolysis with normal guinea- 

 pig serum as complement, but no hemolysis at all when normal 

 rat serum is used as the source of the complement. That is to 



