FEEDING THYMUS TO FROG LARVAE. 



121 



TABLE II. 



APRIL 20. 



Length. 



The length of the larvae in both control and thymus-fed animals 

 was about the same though several slight discrepancies are 

 revealed in Table III. The thymus No. I group shows a slight 

 acceleration in growth (average length) when compared with their 

 liver-fed controls. This acceleration was not shown by the 

 thymus No. 2 group. These small growth differences are shown 

 in Table III. 



The slight difference in the length of the thymus-fed and control 

 animals may possibly be due to the fact that thymus tissue is 

 somewhat more compact than liver tissue and probably presented 

 greater difficulty for the tadpole in eating. Both kinds of tissue 

 were, however, greedily devoured by the larvae. 



OBSERVATIONS OF MAY 4. 



Very faint differences in pigmentation were noticed between 

 the larvae of the thymus-fed and control groups. The thymus- 

 fed animals were slightly darker than their controls which had 

 a reddish tinge. As regards activity, body-shape and mortality, 



