SECT. 12] CYCLOSES, PHOSPHORUS, SULPHUR 



1233 



in weight of the whole embryo. When related to wet weight the 

 glutathione rose to a peak on the 13th day of development, and when 

 related to dry weight it fell all the time in a more or less S-shaped 

 curve. This is shown in Fig. 397. Later on, Sagara injected gluta- 

 minic acid and taurine into hen's eggs at the beginning of develop- 

 ment, and observed a rise in glutathione subsequently as they 

 developed; but this was so slight that little confidence can be placed 

 in his conclusions. 



Cahn went further into the matter, estimating total, organic, and 

 mineral sulphur in the embryo and the remainder of the egg. His 

 values for glutathione in the 

 embryo did not exactly con- 

 firm those of Murray, for the 

 peak on his wet weight curve 

 came a day or two later than 

 the latter's, but nevertheless 

 the two workers are in sub- 

 stantial agreement. A third 

 investigator, Yaoi, has also 

 found the 14th day peak in glu- 

 tathione per cent, wet weight E ^o 

 and was able to trace it in brain 

 and muscle, as well as in the 

 body as a whole. 



Cahn's data for total, or- 

 ganic, and inorganic sulphur 

 are shown in Fig. 398. Ap- 

 parently the total sulphur in 

 the egg-contents remains at 

 a steady value during development, not receiving any accessions 

 from the shell (though Cahn left this point open). The total sulphur 

 in the embryo rises to about 60 mgm. at hatching, so there is a cor- 

 responding fall in the total sulphur of the yolk, the white and the 

 membranes. As the curves for organic sulphur demonstrate, at least 

 90 per cent, of the sulphur in the embryo and the remainder is in 

 organic form, chiefly, no doubt, combined with the proteins as 

 cystine. In addition to all this, the organic sulphur of the whole egg 

 shows a slow and gradual decline to the extent of some 10 mgm., and 

 there is a corresponding rise in the inorganic sulphur, most of which 



