Aug. i8,1923 
Gossypol in Cottonseed 
287 
This study, then, deals solely with the maximum variation of the 
gossypol content of cottonseed and the correlation of the gossypol content 
with the oil and protein content of the seed. No consideration is given 
to the biological factors that might cause the gossypol content to vary. 
No consideration is given to methods of selection, breeding, or cultiva¬ 
tion that might lead to the production of seed of low gossypol content. 
SOURCES OF SEED EXAMINED 
Samples of most of the standard varieties and some of the same variety 
from different localities were secured. Most of the seed examined was 
obtained through the offices of O. F. Cook and R. A. Oakley, of the 
Bureau of Plant Industry, United States Department of Agriculture y 
which maintains an inspection of plantations on which its seeds are 
grown. Therefore, there can be no doubt as to the authenticity of the 
varieties of the seed furnished. A few samples were obtained directly 
from planters, experiment stations, or dealers. 
METHODS OF EXAMINATION 
Only the kernels or meats of the seeds were examined. Usually a 
very small quantity of hull and lint, which could not be removed from 
the ground material by sifting, was present. Gossypol was isolated as 
the “acetate’* by the methods of Carruth ( 3 ) from all varieties of seed 
used. All samples of gossypol “ acetate ” isolated were examined crystal- 
lographically. Quantitative analysis was made according to the writers’ 
modification of the aniline method of Carruth ( 4 ). The fat and moisture 
determinations upon the samples of material analyzed for gossypol were 
made in the Cattle Food Laboratory, and the nitrogen determinations 
by the Kjeldahl method were made in the Nitrogen Section of the Bureau 
of Chemistry. 
MODIFIED ANIEINE METHOD 
Place 75 gm. of practically hull-free finely ground cottonseed meats in 
a Soxhlet extraction thimble. Extract with ether until the thimble 
which stands in the ether overnight imparts to it no significant yellow 
color. Evaporate the ether completely and transfer the extract to a 
beaker, using petroleum ether to work it over with. If necessary, filter 
it. Use 8 to 10 times as much petroleum ether as the volume of the 
extract. 
After standing overnight, a very small quantity of a fine flocculent 
precipitate appears. This is not gossypol, for while gossypol is not solu¬ 
ble in petroleum ether alone, it remains in the oil-petroleum-ether mix¬ 
ture. Filter off this petroleum-ether-insoluble material extracted by the 
ether and wash the precipitate with petroleum ether. Wash the pre¬ 
cipitate and the filter paper with ether. Filter this ether solution and 
evaporate almost completely. Mix the residuum with petroleum ether 
in order to hold in solution the last traces of oil and petroleum-ether- 
soluble material. Then filter and combine the filtrate with the main 
petroleum-ether solution. Add 1 cc. of aniline and dissolve it in the 
solution by shaking. Unless dissolved, the gossypolaniline compound 
comes out in clusters around the small drops of aniline. 
In from 3 to 7 days later filter the precipitate of aniline-gossypol com¬ 
pound through a tared Gooch crucible and wash it several times with 
