504 EXPERIMENT STATION RECOED, 



stuffs may be due, in a measure at least, to the presence of these meta 

 and pyro compounds." In a paper before the Association of Official 

 Agricultural Chemists in that year he mentions the finding of these 

 two forms of phosphoric acid in aqueous solutions of cotton-seed meal, 

 and raises the question whether they exist in the original cotton seed 

 or are formed as a result of the process of the preparation of the meal. 



Dr. Crawford refers to Professor Hardin's work, and notes the 

 absence of any pharmacological tests to bear out the suggestion made 

 in regard to the relation of these bodies to cotton-seed poisoning. 

 The matter appears not to have been followed up by that station until 

 last June, when a project was entered upon with that work and 

 liA^pothesis as its starting point. 



A variety of confirmatory experiments were conducted by Dr. 

 Crawford, together with studies on the nature of the compound, and 

 pharmacological tests with sodium salts of the three forms of phos- 

 phoric acid. Ilis final conclusion is that " the chief poisonous prin- 

 ciple in certain cotton-seed meals is a salt of pyrophosphoric acid. In 

 some this salt seems to be a simple one, presumably inorganic, while 

 in others it is more complex, perhaps an organic one. Probably this 

 difference in the combinations of pyrophosphoric acid may aid in 

 explaining the variation in toxicity of different meals. In certain 

 cotton-seed meals one would expect to find salts of metaphosphoric 

 acid entering into this action. To be harmful the pyrophosphates 

 must be in such a form that they can be absorbed, or the phosphoric 

 acid ionized in the gastro-intestinal tract. The harmlessness of cer- 

 tain cotton seeds and meal is mainl}^ due to the fact that in them the 

 ]:)hosphoric acid exists largel}^, if not entirel}^, as a compound of ortho, 

 and not as one of the other phosphoric acids. Small amounts of 

 pyrophosphates can apparently be borne without injury. The 

 amount of the salt which may be permitted in cotton-seed meal should 

 be determined." 



Aside from the avoidance of too high heating in manufacture, the 

 author does not suggest a remedy for this difficulty in feeding cotton- 

 seed meal. He points out that " at present it would seem to be the 

 wisest course to test each lot of meal by a combined biological and 

 chemical method, and if an}^ excess of poisonous properties is present, 

 to utilize such meal for fertilizing purposes or use for feed Avith the 

 greatest caution, and reserve for more indiscriminate feeding those 

 Avhich prove harmless to experimental animals." 



This work suggests a line of study upon the relation of the char- 

 acter of the soil, etc., to the production of the poisonous body in cot- 

 ton seed, the part which fertilizers may play, the influence of micro- 

 organisms, and an inquiry as to whether the pyrophosphoric acid is 

 derived from the soil or is due to a physiological process in the seeds. 

 The possible relation of cholin or similar bodies as contributory 



