UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 839 
Contribution from the Bureau of Chemistry 
CARL L. ALSBERG, Chief 
Washington, D. C. 
Issued April 23, 1920; revised August, 1922 
THE MICROSCOPICAL EXAMINATION 
OF FLOUR 
By 
GEORGE L. KEENAN, Microanalyst, and 
MARY A. LYONS, Microanalyst, Microchemical Laboratory 
CONTENTS 
Review of Literature 
Purpose of Investigation 
Microscopical Method 
Sources of Variation in Method .... 
Examination of Mill Stocks 1 
Page 
1 
3 
3 
Page 
Examination of Commercial Grades of 
Flour 16 
Examination of Experimental Series of 
Flour , . 29 
Summary 31 
Bibliography 32 
VS 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1922 
