Vol. XXVIII 
APRIL 12, 1924 
No. 2 
JOURNAL OF 
AGRICULTURAL 
RESEARCH 
CONTENTS 
Page 
Types of Vegetation in the Semiarid Portion of the United 
States and Their Economic Significance 99 
A. E. ALDOUS and H. L. SHANTZ 
(Contribution irom Department of the Interior and Bureau ol Plant Industry) 
The Development of American Foulbrood in Relation to the 
Metabolism of Its Causative Organism - - - - 129 
A. P. STURTEVANT 
(Contribution from Bureau of Entomology) 
Brittle Straw and Other Abnormalities in Rye - - - 169 
F. R. DAVISON, H. E. BREWBAKER, and N. A. THOMPSON 
(Contribution from Minnesota Agricultural Experiment Station) 
Relation between Toxicity of Cottonseed and Its Gossypol 
Content - - - - - - - - - - - 173 
ERICH W. SCHWARTZE and CARL L. ALSBERG 
(Contribution from Bureau ol Chemistry) 
Pharmacology of Gossypol ------- 191 
ERICH W. SCHWARTZE and CARL L. ALSBERG 
(Contribution from Bureau of Chemistry) 
PUBLISHED BV AUTHORITY OF THE SECRETARY OF AGRICULTURE 
WITH THE COOPERATION OF THE ASSOCIATION 
OF LAND-GRANT COLLEGES 
WASHINGTON, D. C. 
GOVERNMENT PRINTING OFFICE 
