160 COAL-TAR COLORS USED IN FOOD PRODUCTS. 



For all but No. 201 contradictoiy statements occur in the compiled 

 literature; for No. 201 only unfavorable reports were found. 



There were on the United States market in the summer of 1907 the 

 following oil-soluble colors : 



10. Sudan G (anilin-azo-resorcin) (1). 



11. Sudan I (anilin-azo-b-naphthol) (2). 



49. Sudan II (xylidin-azo-b-naphthol) (1). 



60. Carminaph Garnet (a-naphthylamin-azo-b-naphthol) (1). 



Of these No. 11 had been reported on contradictorily, and the 

 remaining three had not been reported on at all. In addition to these 

 the following three oil-soluble colors, not listed in the Green Tables 

 and not reported on in literature, were wanted: 



1. o-Toluidin-azo-b-naphthylamiii (which does not seem to be described in litera- 

 ture in any way). 



2. Amidoazo-toluol. 



3. Anilin-azo-b-naphthylamin. 



So that out of a total of seven oil-soluble colors on the United 

 States market in the summer of 1907 only one had been examined 

 physiologically and that with contradictory results. As before 

 stated, these oil-soluble colors all belong to the class of nonsulpho- 

 nated azo-colors. 



Fraenkel (p. 575) says: "When, however, the azo-colors contain 

 no sulpho-group (i. e., are nonsulphonated) they are poisonous. 

 Thus for example, Bismarck Brown * * * Sudan I." Yet 

 meta-nitrazotin, a nonsulphonated color not in the Green Tables, 

 and probably not upon the market anywhere, and which is meta- 

 nitranilin-azo-b-naphthol, is according to Weyl nonpoisonous. 



Fraenkel (p. 575) also stated: 



The fact that the monazo colors examined by Cazeneuve and Lupine are harmless, 

 as above stated, is equally explained by the constitution of these substances. Those 

 two investigators examined (omitting the trade names) a-naphthylamin-sulphoacid- 

 azo-a-naphthol-a-sulphoacid, a-naphthylamin-sulphoacid- azo - b - naphthol - disulpho- 

 acid, a-naphthylamin-azo-b-naphthol-disulphoacid, xylklin-azo-b-naphthol-disulpho- 

 acid, sulphanilicacid-azo-a-naphthol, Amido-azo-toluene-disulphonicacid. 



These substances are all sulphoacids and the sulpho-groups here effect the depoison- 

 ing of the original substance. 



Examining this statement it therefore appears that in FraenkeFs 

 opinion, at least, a-naphthylamin-azo-a-naphthol, a-naphthylamin- 

 azo-b-naphthol, xylidin-azo-b-naphthol, anilin-azo-a-naphthol, and 

 amido-azo-toluol are in and of themselves poisonous substances, and 

 are rendered nonpoisonous by sulphonation. Diligent search through 

 the literature has failed to uncover any original communications of 

 investigators to that effect. 



With but one known exception all the nonsulphonated azo-colors 

 are regarded by Fraenkel as poisonous. The colors 17, 18, 41, 197, 

 and 201 on page 159 are not used as oil-soluble colors and therefore 

 form no comparative basis for judging oil-soluble colors except that 



