424 Journal of Agricultural Research voi. xiii. no. s 



the passage of light, never lost their gossypol reaction; moreover, little 

 or no anthocyan was found, either in the glands or the petals. 



With the unfolding of the cotyledon in the seedling the preformed 

 gossypol undergoes a change; it gives a brownish or greenish emulsion 

 or solution with sulphuric acid. The anthocyan pigments give a similar 

 but less intense red with sulphuric acid; they, moreover, react with acid 

 in any strength, while gossypol develops the red coloration only with 

 concentrations of 80 per cent (volumetric) or more, and the coloration 

 is immediately lost if the gossypol-red solution be diluted below this 

 strength. 



Table I, which gives the microchemical reactions of the contents of the 

 gland chambers of jDarts exposed and not exposed to light, is herewith 

 appended. The more important reactions are compared with those of 

 pure quercetin and quercimeritrin, prepared in this Bureau, and pure 

 gossypol, kindly furnished by Dr. F. E. Carruth, of the North Carolina 

 Experiment Station. Experiments to distinguish quercetin from its 

 glucosids in situ have thus far not been successful. 



