Nov. is, 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.* 1 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 1) 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 (1913). 
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 11 to 14 days (Table X, part 2), while the average lethal period 
for kernels extracted from five to eight hours (Table X, part 1) 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 1 
Animal No. 
Weight of rabbit. 
Weight 
of feed 
eaten. 
Equivalent of feed 
eaten as kernels. 
Num¬ 
ber of 
days 
fed. 
Result. 
Initial. 
Final. 
Gain or 
loss. 
Total. 
Daily. 
940 . 
93 S. 
952 . 
947 . 
958 . 
959 .. 
Guinea pig B 
(second period) 
970 . 
974 . 
Gw. 
2,100 
1,38° 
1,480 
1,875 
1,430 
2,560 
610 
I. SIS 
I. S!0 
Gm. 
1. <>S 5 
1, 500 
1,678 
i.S 76 
!, 3 l8 
2,165 
S 3 5 
1,670 
i> 52 S 
Gm. 
-455 
+ 120 
+ 198 
-300 
—112 
-395 
- 85 
+155 
+ 15 
Gm. 
348 
568 
251 
605 
494 
882 
199 
285 
458 
Gm. 
522 
852 
373 
909 
74 i 
1,323 
300 
420 
687 
Gm. 
14 
II 
20 
17 
15 
21 
9 
21 
14 
35 
75 
19 
53 
52 
64 
34 
20 
50 
Died. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
Do. 
& 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. 
6 Rabbit 651 and guinea pig B werefedfor two separate periods, therebeing a rest of two weeks between 
the two periods. 
