Apr. 12, 1924 
Toxicity of Cottonseed and Its Gossypol Content 187 
DISCUSSION 
The experiments in which pure gossypol dissolved in peanut oil was injected 
intraperitoneally and those in which the ether extract of different varieties of 
cottonseed was injected intraperitoneally show a general similarity in toxicity. 
The Egyptian and Durango seeds showed the toxicity that was to be expected 
from their gossypol content. The Lone Star and the Trice seeds, however, 
deviated somewhat from the expected toxicity. Chemical analysis of the seeds 
studied showed an extreme range in gossypol content of 300 per cent, whereas 
the range in toxicity of the ether extract from these seeds was from 400 to 450 
per cent. This was due, not to a toxicity of the seeds in gossypol greater than 
that corresponding to their gossypol content, but rather to a lower toxicity of 
the seed relatively low in gossypol. It is to be expected, of course, that where 
the gossypol content is low, the errors of the analytical method will be exag¬ 
gerated as compared with those seeds in which the gossypol content is high. 
Furthermore, it is to be expected that decomposition and modification of the 
gossypol will be relatively greater in the seeds with a low gossypol content than 
with those having a high gossypol content. These are the main factors in ac¬ 
counting for the differences between the calculated and the observed toxicity 
of different quantities of seed. The conclusion that the experiments with the 
intraperitoneal injection of gossypol itself and of ether extract of cottonseed 
show that the two are equally toxic and that gossypol is the only or at any rate 
the predominant toxic principle of cottonseed, seems to be warranted. 
The feeding experiments with diets containing either added pure gossypolor raw 
cottonseed kernels added to the diet in such proportion that the gossypol content 
of the total diet was known show the same parallelism between gossypol content 
and toxicity. For diets containing quantities of gossypol large enough to cause 
death or arrest growth in a relatively short time this is entirely clear. With 
smaller quantities in the diet such parallelism, of course, is much less clear and 
is not to be expected. The symptoms observed from feeding gossypol and 
cottonseed kernels were similar. They consisted of loss of appetite and depression 
of growth, which, if sufficient quantities of gossypol or of cottonseed kernel had 
been fed, often led to death, if the feeding was continued. If the feeding was 
discontinued and the animals changed to control diet, growth was resumed'at 
varying rates. There was some evidence that animals were permanently injured 
when fed for long periods on the gossypol or raw cottonseed kernel diets. 
The results herein recorded could not have been due to any defect of the diet 
as such. A superabundance of protein, of vitamin, of salt, etc., was furnished 
so as to give the best opportunity for growth and to diminish as much as possible 
any indirect effect of the poison. Moreover, when additions were made to the 
control diet, care was taken to keep the protein content of the diet practically 
the same. It is obvious that merely to have added cottonseed products to the 
control diet would have changed its character, particularly with respect to 
protein, and would have introduced a further variable into the experiment. 
Perhaps the results obtained in this investigation explain the discrepancies 
between the experiments of Richardson and Green ( 8 ) and those of Osborne and 
Mendel ( 6 ) with 9 per cent of protein (in the form of cottonseed flour) in the diet. 
Different degrees of growth were obtained. The reason for this may lie in the 
gossypol content of the different samples of cottonseed flour used by these inves¬ 
tigators. At that time it was impossible to estimate the gossypol content, for no 
methods had been developed. 
It is evident that henceforth a knowledge of the gossypol content is essential in 
any investigation of the toxicity and nutritional value of cottonseed press cake. 
Moreover, the data presented in this paper do not permit generalizations concern- 
