iSo 



PROBLEMS OF RELATIVE GROWTH 



to a considerable dosage, above which no further increase of 

 reaction is obtainable, a function of the amount of hormone 

 administered. Champy (1922), as a result of investigations 

 on thyroid-fed frog tadpoles, concludes that thyroid, during 



Fig. 80. — To show disproportionate reduction by starvation of a heterogonic 

 organ (male dorsal crest) in a male newt, Triton cristatus. The drawings are 

 to scale, and were made at o, 5, 9, 16, 24, 32, and 45 days from the beginning 



of starvation. 



