262 Journal of Agricultural Research voi. v. No. : 



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. 



Friemann (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 per 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 

 afifected the toxic principle. A noteworthy fact is that the neutralized and 

 evaporated extract was shown to be nontoxic. 



Withers and Brewster (191 3) 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 gasoUne. 

 Gossypol was separated from the ethereal solution by evaporation, by 

 precipitation with petroleum ether, or by precipitation with acetic acid. 



