316 MATSUZIRO TAKENOUCHI 



Under ether narcosis the blood of the rats was taken from the 

 arteria carotis and the thymus gland was removed under aseptic 

 precautions, avoiding the mixing of blood as completely as pos- 

 sible. After being weighed, the glands were washed in sterile 

 saline solution to free them from visible traces of blood and 

 then were ground with sterile salt solution into an emulsion, 

 which was strained through sterile cotton gauze and injected 

 into the rabbit intraperitoneally. 



The injection was repeated three or four times with increasing 

 doses of the thymus emulsion, at about one week's interval, and 

 seven to ten days after the last injection the blood was taken 

 under ether narcosis from the arteria carotis. Autopsy findings 

 were noted. The separated serum was carbolized (0.5 per cent) 

 and kept in the ice-box. 



The normal serum which was used in the control experiments 

 was taken from the ear vein of a normal rabbit without narcosis, 

 carbolized as above, and also kept in the ice-box. 



For the detection of antibodies in vitro, we used the precipitin 

 reaction with the extracts of several organs from normal rats. 

 The technique used in the preparation of the extracts will be 

 given later. 



For the determination of antibodies in vivo, we injected the 

 antithymus serum repeatedly into albino rats, using generally 

 0.3 cc. to 0.5 cc, injecting subcutaneously on the back near the 

 tail, and observing any marked symptoms which followed. Gen- 

 erally one half of one litter of rats was used as the test animals, 

 and the other half as controls. All the rats were fed with ordi- 

 nary laboratory diet. The growth curve was obtained by 

 weighing each rat separately. 



The examination of the test and control rats followed at differ- 

 ent intervals after the last injection of the serum. Under ether 

 narcosis, blood was collected, each organ removed separately and 

 weighed carefully and, directly after the weighing, all the organs 

 were fixed in Bouin's solution for histological study. 



For the comparative study on the specificity of cytolytic 

 serum, I also immunized rabbits with testes from albino rats, 

 using almost the same technique as in the immunization with 



