United States Department of Agriculture, 



BUREAU OF CHEMISTRY Circular No. 29. 

 H. W. WILEY, Chief of Bureau. 



CHANGES IN PROVISIONAL METHODS FOR THE ANALYSIS OF FOODS 

 AND ADDITIONS THERETO, FROM 1902 TO 1905. 



INTRODUCTION. 



The methods for the examination of foods, with special reference to 

 the detection of adulteration, submitted at the meeting of the Associa- 

 tion of Official Agricultural Chemists in 1901, were adopted provision- 

 ally and printed as Bulletin 65 of the Bureau of Chemistry. When 

 these methods were adopted it was expected that they would be greatly 

 amplified and changed as a result of subsequent study. Many of the 

 methods appearing in Bulletin 65 had been carefully w r orked out by 

 the association, but only a few of them were tested by collabora- 

 tive work, and in many cases the methods that seemed to be best 

 adapted for making certain determinations were adopted provisionally 

 without detailed investigation by the association. It is seen, therefore, 

 that the methods in Bulletin 65 were adopted as a working basis, and 

 probably conditions would have been simplified if these methods had 

 first been adopted as tentative rather than as provisional, 



Since the publication of Bulletin 65 man}^ methods have been 

 adopted for subjects not covered in that report, and new methods and 

 modifications have been made provisional. Upon attempting a revi- 

 sion of Bulletin 65 it was found that the changes necessary and the 

 rearrangement needed to meet the growth of the work arid prevent 

 duplication in statement, in both Bulletins 46 b and 65, were so exten- 

 sive that a satisfactory- revision was impracticable (following the pre- 

 'cedents established by the association) without special authorization. 

 For that reason it has been thought best to publish at this time merely 

 the additions and changes that have been authorized by the association, 

 and to suggest at the next convention a comprehensive plan for the 

 revision of all of the methods. 



U. S. Dept. Agr., Bureau of Chemistry, Bui. No. 65, adopted by the Association 

 of Official Agricultural Chemists, November 14-16, 1901. 



& Methods of Analysis, adopted by the Association of Official Agricultural Chemists, 

 November 11, 12, 14, 1898. 



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