Jan. 14, 1918 Gossypol, the Toxic Substance in Cottonseed 



99 



in the cooking of the products, as we have found these to be the greatest 

 cause of variation in toxicity of meals. 



Richardson and Green (u, p. 316), state in conclusion: 



Our results indicate that cottonseed meal does not contain sufficient minerals for 

 growth, is not actively toxic, contains efficient protein and perhaps fat-soluble, growth- 

 promoting substances, similar to those of butter fat, but in less adequate quantities. 



Our own extensive unpublished experiments on the toxicity of cotton- 

 seed products indicate that the toxicity of cottonseed meals varies with 

 the conditions of cooking the raw seed. While we find that the flour 

 and thoroughly cooked meals have no apparent toxicity for rats when 

 fed in diets supplemented by milk powder, these same products fed in 

 unsupplemented diets are inferior to ether-extracted cottonseed kernels. 

 Even thoroughly cooked cottonseed meals are definitely injurious to 

 rats and pigs. 



The ash analysis of cottonseed flour given by Richardson and Green 

 (ii, 12, ij) in each of these three articles differs radically in some respects 

 from that given by Forbes (i) (Table X). 



Table X. — Ash analyses of cottonseed flour 



Constituent. 



Inorganic salts 



Silicic oxid (Si02) 



Chlorin 



Sulphur trioxid (SO3) 



Phosphorus pentoxid (P2O5) 



Potassium oxid (KgO) 



Calcium oxid (CaO) 



Magnesium oxid (MgO) 



Sodium oxid (NajO) 



Analysis 

 of cotton- 

 seed flour 

 according 

 to Rich- 

 ardson 



and 

 Green. 



Per cent. 



5-5° 



o. 14 



None. 



.06 



2-57 



2. 01 



.26 



•25 

 None. 



Constituent. 



Ash 



Chlorin. . . . 

 Sulphur. . . . 

 Phosphorus 

 Potassium . . 



Calcium 



Magnesium . 

 Sodium . . . . 



Analysis 

 of cotton- 

 seed meal 

 according 

 to Forbes. 



Per cent. 

 7. 629 



. 042 

 •536 

 1.479 

 I. 81 

 . 291 



•599 

 .283 



Richardson and Green's data are from an analysis of material left after 

 ignition, which, as is well known, causes loss of elements, such as sulphur 

 and chlorin. While the elements chlorin and sodium are not necessary 

 for plant growth and the amounts present may vary, it seems hardly 

 possible that they are entirely lacking in cottonseed flour. They are 

 certainly essential to animals. It may be noted that the rats of Richard- 

 son and Green "have grown and maintained body weight for 135 days" 

 on a diet containing cottonseed flour as the sole source of minerals. 



In their second article Richardson and Green (12) have attempted to 

 repeat some of our work with extracts of cottonseed. Instead of using 

 unheated cottonseed kernels, as we did, they used kernels heated to 

 120° C. Thus, they fail to find toxic the ether extract of petroleum- 



