34 COAL-TAB COLORS USED IN FOOD PRODUCTS. 



Association of the United States, that coal-tar colors designated 

 by it as "colors that are injurious and therefore to be rejected, 

 harmful organic colors" be not used in confectionery, and by implica- 

 tion that they should not be used in other food products. 



In view of this disregard with respect to 13 coal-tar colors out of 

 33 on the United States market in the summer of 1907, dealt with in 

 this confectioners' list, the conclusion seemed justified that the action 

 regarding other coal-tar colors on the United States market in the 

 summer of 1907 was equally heedless or indifferent, a conclusion 

 which is borne out by the material brought together under section IX. 



The necessity of adhering to some unequivocal terminology, as has 

 been done in these pages by referring to the serial numbers in the 

 Green Tables, appears from the following: 



Trade names are not definite with respect to the composition of 

 the article sold under a given name, although tinctorially the colors 

 may be substantially equivalent. In the Green Tables there are not 

 less than 29 instances where the same trade name is applied to two 

 or more different chemical individuals. In some cases these chemical 

 individuals are fairly closely related, in others they are only remotely 

 related. When the differences are greater than the presence or 

 absence of a sulpho group or the use of methyl for ethyl or the reverse, 

 the instances are given below: 



1. Cotton Yellow 128 Primulin-azo-m-phenylene-diamin-disulphonic acid. 



191 Diphenylurea-disazo-bi-salicylic acid. 



2. Methyl Eosin 513 Methylated tetrabromo-fluorescein. 



375 Dinitro dibromo fluorescein. 



3. New Yellow 88 p-sulphanilic acid azo-diphenylamin. 



91 Nitration product of diphenylamin yellow. 



4. Orange III 23 Meta-nitranilin azo-R salt. 



87 p-sulphanilic acid azo-dimethylanilin. 



5. Orange N 43 Toluidin azo-Schaffer acid. 



88 p-sulphanilic acid azo-diphenylamin. 



6. Orange R 97 o-toluidin-monosulphonic acid azo-betanaphthol. 



15 Anilin-azo-R salt. 



99 Xylidin sulphoacid-azo-betanaphthol. 



7. Toluylene Red 261 Dichloro-benzidin disazo R salt. 



580 Dimethyl diamido toluphenazin. 



The following quotation also bears on this point : 



In attempts to group the aniline colors a kind of uncertainty appears even among 

 color chemists. The same trade name does not always correspond to the same prepara- 

 tion. Many preparations are not chemical individuals, but mixtures of related colors. 

 Many preparations are "standardized" for the trade; for example, with dextrin. On 

 account of the patent laws, factory secrets surround the production of many coloring 

 matters, and frequently statements are met with which are directly intended for the 

 purpose of misleading competition. (Hueppe, Die Methoden der Bakterienforschung, 

 5th ed., 1891, p. 105.) 



