Nov. 15.1915 Gossypol, the Toxic Substance in Cottonseed Meal 279 



extracted for five to eight hours with ethyl ether in a filter-paper thimble 

 in a large Soxhlet apparatus." After extraction the residual ether was 

 evaporated and the kernels sifted through a i-mm. sieve. They were 

 either heated for an hour or so over a steam bath or dried in the air. 



Sixteen rabbits and two guinea pigs were fed upon ether-extracted 

 kernels. One of the rabbits had its back broken on the fifteenth day 

 and was chloroformed. It showed none of the usual symptoms of 

 cottonseed-meal feeding. Nine of the animals (Table X, part i) died in 

 from 19 to 75 days and 8 (Table X, part 3) were alive and normal at the 

 end of the feeding experiments, which ranged from 42 to 71 days. Calcu- 

 lated to the average daily equivalent of kernels per kilogram of initial 

 live weight, 9.4 gm. of ether-extracted kernels proved lethal to nine 

 rabbits after 45 days, while 11.5 gm. did not prove lethal to eight others 

 after 52 days. The ether-extracted kernels are therefore much lower in 

 toxicity than cotton seed meal, of which a daily feed of 6.5 gm. per kilo- 

 gram for 13 days was found lethal by Withers and Brewster (191 3). 



In view of the strikingly positive results obtained with ether extract 

 and gossypol isolated therefrom, it was naturally expected that the 

 ether-extracted kernels would prove nontoxic. With death resulting 

 to only 9 out of 17 animals, and then not until after an average of 45 days, 

 it is not unlikely that if the ether-extracted kernels had been fed in as 

 small quantities as the cottonseed meal (6.5 instead of 9.4 gm.) they 

 would have proved practically nontoxic, as anticipated. 



The thoroughness of extraction is very important, as shown by the fact 

 that kernels through which ether had only percolated proved toxic in 

 from II to 14 days (Table X, part 2), while the average lethal period 

 for kernels extracted from five to eight hours (Table X, part i) was 45 

 days, or more than three times as long (Table X). 



Table X. — Results of feeding ether-extracted cottonseed kernels (feed 316) to rabbits 

 PART I 



940 



935 



952 



947 



958 



959 



Guinea pig B 

 (second period)^. 



970 



974 



Weight of rabbit. 



Gm. 

 2, 100 

 1,380 

 I, 480 

 1,87s 



1,430 

 2,560 



610 



1,515 



Gm. 

 1,655 



1, 500 

 1,678 

 1,576 

 1,318 



2, 165 



535 

 I, 670 



1,525 



Gm.. 

 -455 

 -f-120 

 + 198 

 -300 



— 112 

 -395 



- 85 



+ 155 

 + 15 



Weight 

 of feed 

 eaten. 



Gm. 

 348 

 568 

 251 

 605 

 494 

 882 



199 

 285 

 458 



Equivalent of feed 

 eaten as kernels. 



Total. Daily 



Gm. 

 522 

 852 



373 



909 



741 



1,323 



300 

 420 



687 



Num- 

 ber of 

 days 

 fed. 



Died. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 



Do. 

 Do. 

 Do. 



_ o Before the ether extraction the ground kernels were extracted with petroleum ether or gasoline in case 

 It was desired to work up the ether extract for gossypol. 



b Rabbit 65 1 and guinea pig B weref ed for two separate periods, there being a rest of two weeks between 

 the two periods. 



