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Journal of Agricultural Research 
Vol. V, No. 7 
an average, 8.3 per cent of initial body weight was sufficient to cause death. 
These authors make the following statement in regard to these tests: 
As a rule the rabbits ate the meal well during the first few days and made gains in 
weight. But towards the end they began to refuse the meal in whole or in part and 
soon thereafter died. 
There have been numerous suggestions as to the cause of poisoning 
and death from the feeding of cottonseed meal. These are summarized 
in the Experiment Station Record (1910, p. 501) as follows: 
It has been variously ascribed to the lint, the oil, the high protein content, to a 
toxalbumin or toxic alkaloid, to cholin and betain, to resin present in the meal, and 
to decomposition products. 
Pathogenic organisms and certain fungi have also been suggested. 
Eriemann (1909), a veterinarian, obtained from the alcoholic extract 
of cottonseed meal which had caused sickness in cattle a base the plat¬ 
inum salt of which contained 28.75 P er cent of platinum. The free base 
had a paralytic action on exposed frogs' hearts similar to muscarin. He 
concluded that the toxicity was to be referred to ptomains which result 
from the nitrogen-containing components of the lecithin, and that un¬ 
saturated fatty acids probably contributed to the total action of the meal. 
Crawford (1910) concluded that “the chief poisonous principle in cer¬ 
tain cottonseed meals is a salt of pyrophosphoric acid." This conclusion 
is discussed later in this article. 
Withers and Ray (1913b) found that the toxicity of cottonseed meal 
could be destroyed by boiling it with alcoholic caustic soda. This was 
the only solvent of a large number used which removed or appreciably 
affected the toxic principle. A noteworthy fact is that the neutralized and 
evaporated extract was shown to be nontoxic. 
Withers and Brewster (1913) found that if a solution of iron and 
ammonium citrate was fed with cottonseed meal rabbits did not die during 
a period about seven times as long as the feeding period when iron salts 
were omitted. Furthermore, rabbits made sick on the meal recovered 
when the iron solution was supplied with the meal. 
PREPARATION OF GOSSYPOL 
Our recent experiments have led us to believe that gossypol is the 
toxic substance of cottonseed. 
In our previous experiments we used cottonseed meal as the material 
for study, but in the experiments discussed in this paper we used cotton¬ 
seed kernels as the initial substance, as gossypol is more readily and more 
completely extracted from the kernels than from the meal. Generally 
speaking, the meal and the kernels are toxic to rabbits to the same degree. 
We extracted gossypol from ground cottonseed kernels with ethyl ether, 
after previously removing most of the oil with petroleum ether or gasoline. 
Gossypol was separated from the ethereal solution by evaporation, by 
precipitation with petroleum ether, or by precipitation with acetic acid. 
