324 



MATSUZIRO TAKENOUCHI 



vember 1, 1918, when the examination was made. This was 

 due to the ' dipping' of the rats in soap-kerosine emulsion on the 

 afternoon of October 31st, just after the body weight had been 

 taken. This matter must be taken into consideration in the 

 interpretation of the histological findings in various organs of all 

 rats in these series. 



The third antithymus serum was obtained from one rabbit 

 (rabbit, group A, no. 3) immunized by four injections of rat 

 thymus emulsion, beginning October 7, 1918, and the blood was 

 taken on November 8, 1918. The serological tests on precipitin 



BODY WEIGHT GRAMS 



±i±i 



Chart 2 The average growth curve, series no. X, XI, and XII. The graph 

 with dots marks the test series and the arrows show the age at which injection 

 was made. The graph with circles marks the controls. 



and hemolysin yielded the same results as in the cases of the first 

 and second serum. 



Three litters of albino rats at the age of fifty days were taken 

 for the experiments. The antithymus serum was injected into 

 one half the members of each litter five times, with several days' 

 interval, while into the other half nothing was injected (controls). 



The relation of the weight of the thymus of all these rats to 

 the body weight and to the age at the time of examination is 

 given in table 4. The computed relative values for the thymus 

 given in the last column of the table are based on the standard 

 values in table 72, of The Rat (Donaldson, '15). 



