FREE AMINO ACIDS IN ANIMAL TISSUE 303 
4 tna ge 
mye 
| 






89 oe BB 
Figs. 83-90. Fig. 83: brains of 3.5-cm tadpole. Fig. 84: 4-cm tadpole. Fig. 85: 7-cm tadpole. 
Fig. 86: adult frog (ltana catesbeiana). Fig. 87: brains of chick embryos on 4th day. Fig. 88: 
8th day. Fig. 89: 13th day. Fig. 90: 17th day of incubation. Taurine, 5; hydroxyproline, 
y-aminobutyric acid, 22. Unlabeled arrows point to y-aminobutyric acid. 
7) 
age of the embryo. As in the case of the previously discussed species, GABA was the 
only detectable constituent that showed progressive changes during the course of 
development. The results in Figs. gt-9g8 show the changes in different parts of the 
chick embryo brain between 15 and 21 days of incubation. There was relatively 
large quantities of GABA early in development in the optic lobes (Figs. 95, 96) and 
the diencephalic structures (Figs. 97, 98) while the cerebellum (Figs. g1, 92) and 
References p. 348/349 
