168 COAL-TAR COLORS USED IN FOOD PRODUCTS. 



found, and, in fact, four references were found favorable thereto and 

 three unfavorable thereto; thus eliminating 55 from consideration, 

 leaving 53, 54, and 56. 



The Austrian law of January 22, 1896 (see Lieber, p. 15), permits 

 the use of azo colors derived from higher homologues of anilins, 

 beginning with xylidin and sulphonated betanaphthols. As Nos. 53 

 and 54 were both derived from xylidin, it was regarded as safe to 

 assume that they would probably be as objectionable as 55. This 

 left 56 only to be considered, which color is derived from cumidin 

 and R-salt. The cumidin portion satisfies the Austrian law and also 

 satisfies the general law laid down in Fraenkel (p. 162), namely, that 

 the greater the number of ring-methyls the less the toxic property of 

 the resulting compound, because of the oxidation of these methyls to 

 carboxyls in the animal system; the R-salt portion satisfies the gen- 

 eral law laid down in Fraenkel, that the more highly sulphonated the 

 less toxic a substance becomes, and therefore 56 is in the first portion 

 of its composition of such a nature as to be less objectionable than 55, 

 if 55 be objectionable. 



This combination of facts, namely, the desirability of an ariilin 

 azo-red, the provision for diminishing the toxicity of 55 by the sub- 

 stitution of cumidin for xylidin therein, and the general provision 

 in the Austrian food law, made it appear desirable and safe to take 

 into account an anilin azo-red, and therefore to select 56 as probably 

 the least objectionable, if it be at all objectionable, of the anilin 

 azo-reds. 



The full list of permitted colors was therefore extended to 7, as 

 follows : 



Red shades. 107. Amaranth; 56. Ponceau 3R; 517. Erythrosin. 



Orange shade. 85. Orange I. 



Yellow shade. 4. Naphthol Yellow S. 



Green shade. 435. Light Green S F yellowish. 



Blue shade. 692. Indigo disulpho acid. 



It should be noted that with respect to tetra-iodo-fiuorescein, 517 

 of the Green Tables, no specific investigation, pronouncing it harmless 

 or harmful, is described in the literature. No. 516, the diodo-fluores- 

 cein, is reported specifically adversely in the literature, especially by 

 Chlopin; the Confectioners' List, the laws of Austria, the laws of 

 France, the rather superficial examination of No. 517 by Grandhomme, 

 and the statement in Fraenkel (p. 574), that it produces no disturbance, 

 are all taken to apply to 517 and not to 516. The identification of the 

 color Under examination with 517 has not in all cases been satisfac- 

 torily exclusive, but it is believed that the differentiation of the 

 harmful 516 by Chlopin makes all the other references cited pertinent 

 to 517. 



