FREE AMINO ACIDS IN ANIMAL TISSUE 299 
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Figs. 59-64. Fig. 59: chromatogram of extract corresponding to 150 mg of fresh weight of albumen 
from chick embryo at 18 days of incubation. Fig. 60: chromatogram of acid hydiolysate of 1.5 mg 
of the dried, alcohol-extracted albumen. Figs. 61-64: chromatograms of alcoholic extracts of 
150 mg of yolk before incubation (Fig. 61) and at 3, 16 and 18 days of incubation (Figs. 62, 63, 
64, respectively). 
extracts of fetal mouse liver showed that glutamine was not detectable until the 
19th day of gestation, at which time the pattern of amino acids only differed from 
that found in the adult mouse liver by having less glutamine and glycerylphos- 
phorylethanolamine (Figs. 69-72). 
Figs. 73-75 show chromatograms of extracts of heart obtained from 16-day fetal 
mice (Swiss), 1-day-old mice and adult mice, respectively. Extracts of the heart of 
fetal mice between 16 and 1g days of gestation (results shown only for 16 days) and 
of newly born mice contained higher concentrations of a number of the amino acids 
References p. 348/349 
