286 Journal of Agricultural Research voi. v. No. 7 



(i) Extraction of the kernels with ether (feed 316) or with ether and 

 with alcohol (feed 331). By these methods gossypol is reduced to such 

 a small amount that the residue is only slightly toxic (feed 316) or is non- 

 toxic (feed 331). 



(2) Treatment of the meal with an alcoholic solution of an alkali 

 (Withers and Ray, 1913b). This treatment affords conditions for rapid 

 oxidation, and oxidized gossj^pol has been found by us to be nontoxic 



(feed 338). 



(3) Treatment of the meal with iron salts (Withers and Brewster, 

 1913) and Withers (1913). Treatment with iron salts is accompanied by 

 some chemical action, as shown by the pronounced change in the color of 

 the meal. The favorable physiological changes may be due to oxidation 

 of the gossypol or to the formation of a more difficultly soluble compound. 

 The oxidation may be due to the stimulating action of iron upon the 

 oxidases of the animal body or to the direct action which ferric salts exert 

 upon phenolic bodies. Ferrous sulphate forms an insoluble lake with 

 gossypol. We have not yet studied it, but as Marchlewski (1899) found 

 the lead salt so stable that it was not decomposed by hydrogen sulphid 

 nor sulphuric acid, it is likely that the iron lake is very stable also. 



The seed tissue surrounding the cells probably prevents the free action 

 of reagents which would extract gossypol or render it physiologically 

 inert. This constitutes the principal difficulty that must be overcome by 

 the oil miller or stock feeder in rendering cottonseed meal nontoxic. 



SUMMARY 



(i) Gossypol, first isolated by Marchlewski from cottonseed oil and 

 considered by him a prospective dyestuff, was extracted by us from 

 cottonseed kernels and found to possess toxic properties. 



(2) Cottonseed kernels were used as the initial material instead of 

 cottonseed meal, because they yield gossypol more readily to solvents 

 and are toxic to about the same extent. 



(3) Ethyl ether was used as the solvent, the kernels having been 

 extracted with gasoline to remove most of the oil. Evaporation of the 

 ether leaves a crude product which we have designated "gossypol 

 extract." A purer product, "precipitated gossypol," was obtained from 

 the ethereal solution by the addition of gasoline, and a crystalline 

 product, "gossypol 'acetate,'" by precipitation by acetic acid. 



(4) Gossypol was fatal to rabbits when administered intraperitoneally 

 in the form of gossypol extract or crystalline gossypol acetate, either 

 when fed in one large dose in the form of gossypol extract or when fed 

 in small daily doses in the form of gossypol extract, precipitated gossypol, 

 or gossypol "acetate." 



(5) Gossypol forms an oxidation product which is nontoxic. 



(6) Cottonseed kernels are rendered less toxic by the partial extrac- 

 tion of gossypol and nontoxic by a more nearly complete extraction of it. 



