THE JOURNAL OF PHARMACOLOGY. 77 



Organic Hair and Fur Dyes. 



Erdmann in a lecture before the Association of Industrial Chemists 

 meeting at Frankfurt a\M., calls attention to some of the more important 

 organic dyes, which have been introduced of late years. Such of these 

 that are non-toxic, present decided advantages over the more or less in- 

 jurious silver and lead preparations still in vogue. First among these 



OT-T 

 organic synthetic dyes are para-amido-phenol (C6H4<^-j^jj^ 1.4.) and para- 



phenylene-diamine (C6H4(NH2)2i-4-)- Their value depends upon the 

 readiness with which they darken through oxidation. If the hair or fur 

 is moistened with a solution of either of these bases, and this followed with 

 an application of a weak hydrogen peroxid solution, a permanent dark 

 stain is produced either immediately, or on exposure to the air. White 

 Angora fur, after moistering with a 3-per-cent. solution of p. phenylene 

 diamine, then a 3-per-cent. hydrogen dioxid, will after 15 minutes take on 

 a deep black and, after a few hours, the color will have become so fast that 

 boiling in a soap solution fails to produce any effect. A cross section of 

 such a stained hair will show under the microscope that the dyestuff has 

 penetrated uniformly from the surface to the center. Similar in deport- 

 ment to the above is paramido-phenol which appears commercially as a 

 hydrochlorid in white crystals. When used its solution is mixed with an 

 equivalent amount of alkali. The darkest shades are produced by the dia- 

 mine, while the oxidationcolorsof the amido-phenol are brown to red-brown. 

 Dr. Erdmann states that quinone is formed during oxidation and that 

 this unites with undecomposed portions of the bases and gives rise to dark- 

 brown to black insoluble colors. Among this class of dyes are such photo- 

 graphic developers as metol (methyl-p.-amido-m.-cresol) and amidol fp.- 

 diamido-phenol). If to an aqueous solution of the latter some sodium hy- 

 drate is added, a deep blue is produced, where a drop of ferric chlorid gives 

 a blood red coloration. On furs metol and amidol produce brownish-red 

 tints. Quite a number of substitution products of these bases give oxida- 



CH 



tion colors, thus para-toluylene-diamin (C^Hg <C/j^j| ^^ i- 2. 4- ) deports 



like phenylene-diarain, p.-amido-dimethyl-anilin (NH2.C6H4.N(CH3)2) 

 stains brown with a shade into violet. Amido-p.-oxy-benzoic acid (CgHg.- 

 NHo.OH.COOH) stains hair a bright yellowish red while p.-amido-sali- 

 cylic acid (an isomer) stains light red brown. 



For dyeing human hair all these bases are not to be recommended. The 

 use of para-phenylene-diamin is warned against because of its very irri- 

 tant nature in producing inflammation of the scalp and eczema. The same 

 may be said of di-amido-phenol (amidol). On the contrary para-amido- 

 phenol, which is the parent substance of a number of synthetic antipy- 

 retics, is entirely harmless. Metol likewise belongs to this class. 



V. COBLENTZ. 



