62 ANNL'AL REPUHTS OF DEPARTMENT OF AGRICULTURE. 



On account of the urgency of the deniund from stock regions of 

 the West, tliis work up to the present time has been largely confined 

 to that section of the country, but it is hoped to investigate in the 

 early future a number of similar problems occurring in the East. 



Laboratory work on the nature of the active principles present in 

 poisonous plants and poisonous-plant products has been carried on 

 chiefly at Washington. 



The question of spoiled corn and its relation to pellagra has been 

 under investigation, the agricultural side of the problem only being 

 considered. Toxic substances have been isolated from cultures of 

 organisms occurring on spoiled corn and some new constituents have 

 been isolated. 



PLANT PHYSIOLOGICAL IKVE8TIGATI0N8. 



During the year the problem of the storage of sweet potatoes has 

 been actively investigated. The difficulty of keeping sweet pota- 

 toes has suggested a study of the physiological behavior of this prod- 

 uct under different storage conditions in the hope of finding the 

 cause of the wealmess and of worldng out a convenient method of 

 handling them for long-time storage. 



A physiological study of certain pathological conditions arising 

 in cabbage and spinach in prominent eastern trucking regions has 

 been undertaken. The investigation has shown derangement in cer- 

 tain enzyme relations, and a method for accurately investigating 

 these has been worked out. The curly-top of sugar beets has also been 

 under study. 



The physiological requirements of plants have been much inves- 

 tigated in the past, but certain new considerations have come to 

 attention during late years, which have seemed to demand investi- 

 gation of certain of these problems viewed from the new standpoints. 

 Such a study has been undertaken with very suggestive results. 



The chemical variability of certain important drug plants has been 

 under investigation in the hope that uniform active products might 

 be developed. A good basis for further work has been obtained, and 

 the outlook for success seems good. 



ALKALI AND DROUGHT-RESISTANT PLANT-BREEDING INVESTIGATIONS. 



Investigations during the year have been in large measure di- 

 rected toward ascertaining why some varieties of crop plants endure 

 drought better than others, since it is evident that the best results 

 in variety testing and breeding for drought resistance can only be 

 attained when this problem is solved. It is practically certain that 

 " root pull " is not an important factor, for extensive experiments 

 have led to the conclusion that there is very little difference in the 



