466 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Bleached flour. — The most important work of tlio year has been 

 in connection with the enforcement of the law against bleached flour. 

 This has involved the examination of niimoroiis suspected samples, 

 the investigation of special problems relating to bleaching, and the 

 attendance of two of the chemists at the New Orleans and Kansas 

 City trials. 



About 300 samples of wheat from different sections of the country, 

 representing a great number of varieties and grades, were secured 

 through the Bureau of Plant Industry and ground in an experi- 

 mental mill in the Laboratory of Vegetable Physiology at Washing- 

 ton. The flour thus obtained was examined at the Chicago labora- 

 tory with reference to nitrites. In no case was even a trace of nitrites 

 detected. 



A comparative stud}^ of the effects of bleaching and aging on the 

 physical properties and chemical composition of flour has been car- 

 ried out with patent and clear flours from 15 mills located in different 

 sections of the country. This investigation may be regarded as pre- 

 liminary to a more extensive one planned for the ensuing year. 



In the course of the flour investigations a method has been de- 

 veloped for the determination of the " gasoline number," which is 

 a measure of the amount of yellow coloring matter present in the 

 flour associated with the oil. This method, at first designed merely 

 for detecting bleaching, is believed to have a wide application for 

 determining the color value of unbleached flour. 



Vanilla investigations. — A method of determining vanillin, cou- 

 marin, and the normal lead number in vanilla extracts, developed 

 during the preceding year, was presented at the Denver convention 

 of the Association of Official Agricultural Chemists, and has been 

 used in the examination of 74 vanilla extracts prepared in the labora- 

 tory from as many samples of vanilla beans, representing not only 

 the product of different places of production, but also the different 

 lengths and commercial grades of each. Second extracts prepared in 

 each case from the residue of the first extraction have also been 

 analyzed. It is believed that the results thus obtained will be of 

 value in interpreting the analyses of commercial extracts, and enable 

 the analyst to distinguish genuine vanilla extract from imitations. 



Court work. — Chemists from this laboratory have been called on 

 to present evidence in court cases both at Chicago and other points. 

 The time spent in consultation with district attorneys and in court, 

 including the bleached-flour cases, has been approximately equivalent 

 to that of one person for the whole year. 



CINCINNATI LABORATORY. 



The total number of samples analyzed at the Cincinnati laboratory 

 during the past fiscal year is 1,409, including interstate and import 

 work. About one-sixth of the 1,385 interstate samples were adjudged 

 illegal. Of the domestic samples 101 were milks, 145 fruit products, 

 and 126 flavoring extracts. As the figures show, the milk supply in 

 and around the city of Cincinnati during the past year has received 

 special attention. At the time this work was first undertaken, less than 

 two years ago, nearly 60 per cent of the milk samples were adulter- 

 ated, but when the last milk campaign was conducted, during June, 

 1910, only from 6 to 7 per cent of the samples examined showed 



