ENDOCRINE FUNCTION OF THE THYMUS GLAND 



323 



TABLE 3, B 



Shomng the details regarding the studies on the weight of the thrjmus of the control 



rats 



Precipitin reaction tests with the extracts of several rat organs 

 gave just the same results as were obtained with the first anti- 

 thymus serum. 



For the experiment with the second antithymus serum, three 

 litters of twenty-eight-day rats were used (series no. X, XI, and 

 XII). The injection of the antithymus serum was made on 

 twenty-eighth (0.3 cc.) and on the thirty-sixth, forty-second, 

 and forty-seventh days of age (each 0.5 cc). Into the control 

 animals, representing almost one half of each litter, nothing was 

 injected. The average growth curve is given (chart 2). 



Owing in part to the parasitation of the rats by mites (Lelaps 

 echidninus) and to the effects of dipping to kill these parasites, 

 the growth curve of the rats of all three series was very low as 

 compared with the standards (Donaldson, '15), especially in the 

 latter part of October. We observed a suddfen drop of body 

 weight of the rats in series no. XI between October 31 and No- 



