Nov. IS, 191S Gossypol, the Toxic Substance in Cottonseed Meal 285 



It is quite probable that the animal organism is able to take care of 

 the large amount of proteins and phosphorus compounds, as may be 

 inferred from the results of feed 331. 



The latest published endeavor to ascribe the poisonous effects to a 

 specific chemical substance was by Crawford (1910), whose experiments 

 seemed to point to salts of pyrophosphoric acid. 



The improbability of this conclusion was shown by Withers and Ray 

 (1913a), of this Station, in feeding experiments. Cottonseed meal was 

 extracted with ammonium citrate. This left an insignificant amount of 

 phosphorus in the residue, which was almost as toxic as whole cottonseed 

 meal. 



Edgerton and Morris (191 2) also conducted many feeding experiments 

 with cottonseed and cottonseed meal. They fed sodium phosphate in 

 large amounts and concluded that they had found "no evidence whatever 

 to show that pyrophosphoric acid has anything to do with cottonseed- 

 meal poisoning." 



. Rather (191 2) also studied the phosphorus compounds of cottonseed 

 meal and concluded that there was no evidence that the samples of cotton- 

 seed meal examined contained either pyrophosphoric acid or metaphos- 

 phoric acid. He also states (p. 16) that "the inorganic phosphorus 

 (Forbes' method), in the samples of cottonseed meal examined was less 

 than 5 per cent of the total phosphorus." 



R. J. Anderson (191 2, p. 5) isolated an inosite phosphoric acid very 

 similar to phytic acid and made the following statement : 



The organic phosphoric acid of cottonseed meal gives all the reactions previously 

 attributed to the presence of pyro- and meta-phosphoric acids. But the question 

 whether or not it is also the toxic principle in cottonseed meal remains unanswered. 

 Preliminary experiments carried out with the acid obtained from the purified barium 

 salt on rabbits are not conclusive. Given in 0.5 and i gram doses, both the free acid 

 and its potassium salt produced strong symptoms of distress, but after a few hours the 

 animal regained their normal appearance. Larger doses passed through the bowel in a 

 very short time and no definite symptoms developed. 



It is difficult to determine just what caused the toxicity of the preparations which 

 were used in the experiments described by Crawford. It is evident that very impure 

 substances were fed. 



Since inosite phosphoric acids occur in numerous feeding stufifs other 

 than cottonseed meal — e. g., wheat bran, corn, oats, barley — and since 

 no suspicion of toxicity has occurred in these substances it seems highly 

 improbable that the phosphoric acids in cottonseed meal have any 

 significant action as toxic agents. 



METHODS FOR REMOVING OR DIMINISHING THE TOXICITY OF 

 COTTONSEED 



Three methods have been proposed at the North Carolina Experiment 

 Station and have been found efTective for diminishing the toxicity of 

 cottonseed kernels or cottonseed meal: 



