434 
Journal of Agricultural Research 
Vol. XIV, No. 10 
resultant meal was highly toxic. We have shown practically the same 
thing by feeding kernels and oil extracted by petroleum ether (table I, 
diets 388 and 388A). 
It would seem that by the extraction with ethyl ether of certain cotton¬ 
seed meals and flour, a small amount of toxic substance is removed. 
Thus, 28 per cent of the oil extracted from the flour was unpalatable 
to rats in a milk-powder diet; but when reduced to 7 and 10 per cent, it 
failed to have any noticeable influence (compare diets 372, A and B, 
Table I). In diets 42 8, 
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431, and 432 the ether- 
extracted meal was less 
active (fig. 1). 
It should be noted 
here that cottonseed 
meal is not rendered 
nontoxic for rabbits 
(see diet 411, Table II) 
by ethyl-ether extrac¬ 
tion, a fact which seems 
in harmony with the 
fact that in the ex¬ 
tracted meal there is 
left a substance which 
responds to the tests for 
gossypol. The incom¬ 
plete removal of this 
material thus lessens 
the decisive value of 
experiments with ex¬ 
tracts from cottonseed 
meal. 
Three samples of crude cottonseed oil prepared by hot pressing did 
not prove active in short feeding experiments. Tests made previous 
to feeding showed only traces of gossypol, and hence led us to predict 
this result. On the other hand, we found that in the commercial cold¬ 
pressing process most of the gossypol passed into the crude oil. This 
oil, which contains at least 1.5 per cent of gossypol, was found to be 
highly toxic (see diet 440, Table I, commercial cold pressed). The meal 
was not more active than short-cooked cottonseed meal (compare diets 
439 and 451, Table I.) 
Except in rare instances, cottonseed meal is fed in combination with 
other feeds. It has been found at this Station that steers fed exclusively 
on cottonseed meal and hulls do not thrive as well as where the roughage 
is silage. The meal and hulls in combination may not be fed safely 
for more than 70 to 90 days. 
Fig. 3—Graphs showing the toxicity of cottonseed flour to rats. 
They practically ceased growing after 68 days. A renewed growth 
impetus was shown when ether-extracted raw kernels were substi¬ 
tuted for the flour. The flour contains the moderately toxic sub¬ 
stance D-gossypol. 
