290 
Journal of Agricultural Research 
Vol. XXV, No. 7 
IDENTIFICATION OF GOSSYPOL 
Gossypol was identified as the “acetate*' in all varieties of cotton¬ 
seed (Table III) which were analyzed quantitativly, also in Wine Sap 
(a red-foliage variety), in several samples of gin-run seed, and in Ingen- 
houzia (Arizona wild cotton). In addition, it was secured from a sample 
of commercial cotton-root bark. These preparations of gossypol are 
described as follows, by Dr. Edgar T. Wherry, crystallographer of the 
Bureau of Chemistry, who found the optical properties to be identical 
with those of the preparations which were submitted to the writers by 
Doctor Carruth: 
OPTICAL-CRYSTALLOGRAPHIC properties of gossypol “acetate” 
All of the samples of gossypol submitted proved to be crystalline, 
practically insoluble in the usual organic immersion liquids and well 
adapted for optical-crystallographic study under the microscope. Their 
properties are as follows: 
In ordinary light. —Consists of bright yellow flakes, often rather 
acutely rhombic in outline, or sometimes approximately hexagonal. 
Two or more acute crystals are sometimes grown together to form a 
twin, with a deep reentrant angle at one end. The crystal system is 
apparently triclinic. 
With polarizing nicol. —Pleochroism is very slight, but pseudo¬ 
absorption is marked. 
Refractive indices. —(2o°/D): alpha = 1.530 to 1.540, beta = 1.750 to 
1.760, gamma =1.820 to 1.830, gamma —alpha = 0.290. The grains 
usually lie in positions oblique to the index directions, so that mean 
values are shown. By working over large masses of crystal fragments, 
however, the individual indices can be obtained without great difficulty. 
The evidence for variation in indices from one preparation to another is 
definite. This variation, however, is not associated with any other 
recognizable difference in crystallography, and appears to be due to 
variation in amount of solvent-of-crystallization or perhaps of material 
present in solid solution in the crystals. 
In parallel polarized light, nicols crossed. —The birefringence 
is extreme and interference colors are shown only by the thinnest flakes, 
rarely reaching low orders. Extinction is inclined, the angle varying 
widely with the orientation of the crystals, but being 20° toward certain 
frequently occurring edges. Elongation is often negative, but likewise 
varies with the orientation. 
In convergent polarized light, nicols crossed. —Partial bi-axial 
interference figures are not difficult to obtain. The axial angle 2E is 
large, probably around ioo°. The sign is negative, and dispersion is 
extremely strong and markedly unsymmetrical. 
COMPOSITION OF COTTONSEED 
The results of the gossypol determinations, together with those for 
fat, nitrogen, and moisture content, are given in Table III. 
The data in Table III show that the gossypol content of seed may vary 
by as much as 300 per cent. (Compare Trice, 1918, and Tone Star, 1918, 
with the Egyptian and Columbia, 1918.) The greatest annual variation 
in any one variety, approximately 200 per cent, was observed in Trice 
