320 MATSUZIRO TAKENOUCHI 



investigators. A similar lack of specificity of the antibody in the 

 antiserum produced by injection of rat testis tissue to the rabbit 

 will be mentioned later. 



2. Test of the hemolytic power of this antithymus serum. 

 The antithymus serum from the rabbit does not possess any 

 appreciable amount of hemolysin against the red corpuscles of 

 the rat in vitro. For the test in vivo, 1 cc. of that serum was 

 injected subcutaneously into three rats thirty days of age, taking- 

 three more rats of the same litter as controls. All three rats grew 

 perfectly well and reached normal size. Just the same effect 

 was observed with the antithymus serum from the second and 

 third rabbits (rabbits B and C). 



c. Test of the antithymus serum in vivo 



Three litters of healthy young rats of the same age were taken 

 for this test (series no. I, II, and III). To one half of each 

 litter antithymus serum (from 0.3 cc. to 0.5 cc.) was injected 

 subcutaneously, while to the other half of each litter correspond- 

 ing amounts of normal rabbit serum were injected. All the rats 

 were put under the same conditions and the growth was con- 

 trolled by weighing each rat almost every day. Six to twenty- 

 five days after the last injection, some of the rats, both test and 

 control, were examined for the weights of each organ. 



Histologically, studies of the thymus gland from all the rats 

 were carefully made to see whether there was any histological 

 change caused by the injection of the antithymus serum. 



As an example of the growth of the test and control animals, 

 I will give one chart which shows the average curve of the rats in 

 series II (chart 1). 



In no case of the injection of either the antithymus serum or 

 the normal rabbit serum did we observe any pathological symp- 

 toms like the so-called primary anaphylaxis due to the serum 

 injection, or any sudden decrease of the body weight of rats, 

 such as those reported by Shimizu ('13) in his dogs, after the- 

 injection of antithymus rabbit serum. 



