60 COAL-TAR COLORS USED IN FOOD PRODUCTS. 



2. The most poisonous dyes belong to the Nitro, Azo, Triphenyl, and Thiaz 

 groups, and also to the Auramins. 



3. A whole group of poisonous and harmful dyes is formed by the new sulphid dy 

 known as Vidal's dyes. 



(Page 224.) By the facts and observations quoted above is corroborated the opinic 

 that in general the coal-tar dyes, according to the composition and properties, appe 

 as substances foreign to the animal organism, and may influence harmfully the vit 

 functions, even in those cases when they do not possess distinctly poisonous propertie 

 For this reason many hygienists make it a principle not to allow the coloring of fo< 

 products or of beverages with coal-tar dyes, independently of the fact whether th 

 prove in actual experiments on animals poisonous or not. 



We must therefore agree with M. Rudner that food of the masses require the me 

 far-reaching protection, maintaining them free from foreign additions. 



13. Koenig (Die Menschlichen Nahrungs- und Genussmittel, Berli', 

 1904, Vol. II, p. 462) says: 



Even though the majority of the anilin coloring matters, in view of the sms 

 amounts in which they are generally employed, can not be regarded as directly han 

 ful to health, yet the objections to their use in the coloring of food products for ti 

 purpose of substituting or strengthening a natural color lies in the deception co 

 nee ted therewith * * *. 



14. Fraenkel (Arzneimittel-SyntJiese, Berlin, 1906, p. 570) says: 



It is clear that the coloring property of these chemical substances stands in 

 relation to their physiological actions, but, on the contrary, the physiological actio: 

 depend only upon the general structure of these substances, and therefore upon the 

 membership in definite chemical groups. 



(Pages 574-5.) We see, even in considering this group of substances, that they 

 not possess any specific action, but they are capable of use, preferably by extern 

 application, as antiseptic materials, as materials which in their action stand somewhe 

 between carbolic acid and corrosive sublimate, and whose coloring property, in cons 

 quence of which they were primarily selected, is directly a hindrance in this us 

 since the coloring of the bandages and the hands of the operators and the skin of tl 

 patients certainly can not be regarded as a pleasant occurrence; that the antisep 

 action stands in some relationship to the properties of the substances as coloring matt 

 must be positively contradicted. It depends only on the general structure of t 

 substance, and does not stand in any direct relation to the chromophore and aux 

 chrome groups of the substances, but more closely to the aromatic nucleus. Indee 

 it may happen that an auxochrome group diminishes the antiseptic activity of such 

 substance. 



NOTE. The dyes referred to belong to the Monazo, Disaz 

 Triphenyl-me thane, Xanthin, Azin, and Thiazin classes. 



(Page 92.) The investigations of Ehrlich have shown that basic dyes color the bra 

 gray, and, moreover, they color nerve fiber very well, and are therefore to be regarded 

 neurotropes. The dye acids, on the other hand, do not dye nerve fiber, and in partic 

 lar the substituted sulphonic acids do not dye tissue at all. 



15. Meyer, in his paper on "A preliminary communication on tl 

 toxicity of some aniline dyestuffs" (/. Amer. CTiem. Soc., 1907, v. 

 p. 892), says: 



(Page 893.) " A manufacturing confectioner of this city, for whom I made examin 

 tion of colors used by him, informs me that a yellow color sold as Auramin has su< 



