286 
Journal of Agricultural Research 
Vol. V, No. 7 
(1) 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 gossypol 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 
(1) 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. 
