78 University of California Publications in Zoology [Vol. 11 



In the analyses of various cleavage products, table 10, gliadin 

 and gluten are notable for their high percentage of glutamic 

 acid. Glutamic acid is noted by Abderhalden and Guggenheim 

 as an inhibitor of the tyrosinase reaction when tyrosinase from 

 Russula delica is used. Accordingly gliadin and gluten (made 

 from white flour, dried, ground, and fed in powdered form) were 

 fed to different sets of tadpoles. These foods produce so little 

 growth that the results are very inconclusive. 



The results with liver, yolk and gliadin are as follows (table 

 11): 



Table 11 

 Length measurements of Hyla tadpoles fed on liver, yolk, and gliadin. 



Length measurements represent average length of all the tadpoles in 



a dish. 



Hyla. Experiment started Feb. 24, 1912 



Mar. 5. Liver-fed tadpoles black. Gliadin-fed tadpoles dark, but not 

 so dark as liver, yolk-fed tadpoles lighter with a few very 

 light ones. 



Mar. 14. Liver-fed tadpoles all black; yolk-fed tadpoles — four very light, 

 the rest medium; gliadin, one light, the rest medium. 



Of three sets of Rana tadpoles one was fed on raw flour, one 

 on gluten, and the third on gliadin. Here again the growth was 



so slight that the experiment was unsatisfactory (table 12) : 



Table 12 



Length measurements of Sana tad]ioles fed on flour, gluten, and gliadin. 



Length measurements represent the average length of all the tadpoles. 



Equal number of tadpoles at the beginning of the experiment. 



Eana. Experiment started Feb. 24, 1912 



Length in mm. Number of 



^ ^ ', tadpoles 



Feed Mar. 6 Mar. 25 May 6 



Flour 15.7 19.1 9 



Gluten 15.8 18.5 1 



Gliadin 15.7 



Mar. 25. No noticeable color difference. 



Apr. 10. Only one gluten-fed tadpole left. This one is larger and slightly 

 darker than the average of the flour-fed tadpoles. 



