_Secretary of Agriculture_ Arthur M. Hyde. _Assistant Secretary_ R. W. Dunlap. _Director of Scientific Work_ A. F. Woods. _Director of Regulatory Work_ Walter G. Campbell. _Director of Extension Work_ C. W. Warburton. _Director of Personnel and Business W. W. Stockbebger. Administration_ _Director of Information_ M. S. Eisenhower. _Solicitor_ E. L. Marshall. _Weather Bureau_ Charles F. Marvin, _Chief_. _Bureau of Animal Industry_ John R. Mohler, _Chief_. _Bureau of Dairy Industry_ O. B. Reed, _Chief_. _Bureau of Plant Industry_ William A. Taylor, _Chief_. _Forest Service_ R. Y. Stuart, _Chief_. _Bureau of Chemistry and Soils_ H. G. Knight, _Chief_. _Bureau of Entomology_ C. L. Marlatt, _Chief_. _Bureau of Biological Survey_ Paul G. Redington, _Chief_. _Bureau of Public Roads_ Thomas H. MacDonald, _Chief_. _Bureau of Agricultural Economics_ Nils A. Olsen, _Chief_. _Bureau of Home Economics_ Louise Stanley, _Chief_. _Plant Quarantine and Control Lee A. Strong, _Chief_. Administration_ _Grain Futures Administration_ J. W. T. Duvel, _Chief_. _Food and Drug Administration_ Walter G. Campbell, _Director of Regulatory Work, in Charge_. _Office of Experiment Stations_ --------, _Chief_. _Office of Cooperative C. B. Smith, _Chief_. Extension Work_ _Library_ Claribel R. Barnett, _Librarian_. U. S. GOVERNMENT PRINTING OFFICE: 1930 For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents * * * * * Transcriber Notes Illustrations were repositioned so as to not split paragraphs. End of the Project Gutenberg EBook of USDA Farmers' Bulletin No. 1638, by James Silver and W. E. Crouch and M. C. Betts