86 



Journal of Agricultural Research 



Vol. xn, No. 2 



TabIvE I- — Results of feeding raw cottonseed kernels in milk diets to rats — Continued 



Rat 



No. 



Remarks. 



Diet 368 (20 per cent of ether- 

 extract(equivalent to about 

 60 per centof raw kernels), 

 replacing 20 per cent of 

 lard in control diet 364). 



Do 



Do 



Do 



Diet 369 (0.4 per cent gossypol 

 (equivalent to about 20 per 

 cent of ether extract), re- 

 placing 0.4 per cent of 

 starch in control diet) . 



Do 



Do 



Do 



Diet 373 (o.i per cent of gos- 

 sypol added to control diet). 



Do . 



Do 



The survivor, rat 58, was then 

 put on the same diet minus 

 gossypol. 



51 



30 

 31 

 32 



58 



59 

 60 



Died. 



Discontinued. 

 Do. 

 Do. 



Do. 



Do. 

 Do. 

 Died. 



Discontinued. 



Died. 

 Do. 



Discontinued. 



The sparingly soluble compounds of gossypol w^ith acetic acid and 

 with anilin have been used to estimate the amount of gossypol present 

 in cottonseed kernels. Both methods have given results which show 

 that gossypol exists in cottonseed kernels to the extent of approxi- 

 mately 0.6 per cent. 



In order to explain the change in toxicity in cottonseed after being 

 cooked in the mill, we offer the following hypothesis: Under the action 

 of moist heat the gossypol streams from the glands and is spread over the 

 seed tissue. Part is oxidized to a less toxic substance which we may for 

 convenience call " D-gossypol; " part is left in combination with the bases 

 or protein as a salt of gossypol; and part is expressed in the oil. The 

 degree to which these changes take place is dependent on the method of 

 cooking and the condition of the seed. In dry heating to 100° C. there 

 is practically no decomposition of the gossypol. In very dry seeds the 

 gossypol may not spread over the seed tissue and be changed unless much 

 moisture is added and the cooking prolonged. 



Some quantitative data on the amount of gossypol left in the seed 

 have been obtained from samples of kernels cooked various lengths of 

 time — 5, 10, 20, and 28 minutes. The percentage of gossypol extracted 

 by ether in these cases was, respectively, 0.62, 0.24, o.io, and 0.07. 



