UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 839 



Contribution from the Bureau of Chemistry 

 CARL L. ALSBEKG, Chief 



Washington, D. C. 



April 23, 1920 



[ICROSCOPICAL 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 11 



Page 

 Examination of Commercial Grades of 



Flour 16 



Examination of Experimental Series of 



Flour , . 29 



Summary 31 



Bibliography 32 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1920 



