CONTENTS. 



Page. 



Introduction 9 



Purpose of the investigation 9 



Number of colors permitted 11 



Quality and efficiency of colors permitted 12 



I. Identity of coal-tar colors used in food products in the United States 



hi 1907 15 



Collection of samples 15 



Classification of samples submitted 17 



Green Table numbers 17 



Source 18 



Patents 18 



Shades of color 19 



n. Purposes of food coloring 23 



HI. Food color requirements 25 



Adaptability for special purposes 25 



Proportion of coal-tar color used 26 



Suitability of shades of permitted colors and mixtures of same 28 



IV. Conformity of food color market, 1907, to recommendations of the 



National Confectioners' Association, 1899 30 



V. Some legal enactments relative to the use of coal-tar dyes 35 



List of thirteen foreign legal enactments 35 



Summary of colors permitted by these legal enactments 35 



Colors said to be permitted under the German law of 1887 37 



Definiteness and detail necessary to effect quality control 40 



State laws prohibiting the use of colors in certain foods, 1909 41 



VI. Recommendations by associations and individuals as to use of coal-tar 



dyes as food colors 42 



Cazeneuve and Lepine 42 



Society of Swiss Analytical Chemists 43 



Tschirch 43 



Kayser 44 



Weyl 44 



National Confectioners' Association 45 



Schacherl 4 45 



Classification of recommendations in the literature 46 



Conclusions 47 



VII. Recommendations made by United States color industries and trades 



to the Department of Agriculture 47 



Antagonistic to all added artificial color 48 



Concerning restrictions and requirements 48 



VIE. Investigations, other than on animals, bearing on the harmfulness of 



coal-tar colors 51 



Pfeffer 51 



Winogradow 52 



Heidenhain 52 



Other authors 54 



5 



