88 COSMETICS. 



To understand the principles whereon the imparting of 

 this fashionable golden tint to hair is founded, it is necessary 

 to revert to the chemistry of calcigenous metals. Most of the 

 metals in this category, as I have already announced, when in 

 solution yield a black tint by the reaction of hydrosulphuric 

 acid (sulphuretted hydrogen), and still a few others by hydro- 

 sulphate of ammonia, iron being amongst the number of the 

 latter. Two metals of this class, however, yield a golden- 

 yellow colour under similar treatment ; and this brings us to 

 the point to which we have been tending. The metals in 

 question are arsenic and cadmium; wherefore it should follow 

 from application of the principles already expounded, that 

 whereas a lead component applied to the hair under condi- 

 tions indicated should cause blackness, an arsenical or cad- 

 mium compound should produce yellowness. Now, cadmium 

 is, so far as a metal can be, innocuous; the character of 

 arsenic we all know. It has the evil repute of being a violent 

 poison, and that character it merits. To exaggerate the poi- 

 sonous danger of arsenic, whether taken internally, or applied 

 to the skin, or its fumes breathed, would be difficult. Yet, 

 terrible to state, solutions of this awful poison are slopped 

 upon ladies' heads when the cherished golden tint of hair is 

 aimed at ; and, worse still, sold to ladies for private domestic 

 use. Recklessness could not well farther go, even in the 

 behests of fashion. Many cases of poisoning have already 

 occurred from this cause, the origin unsuspected. What 

 appears to me strange is, that cadmium compounds, though 

 comparatively harmless and yielding a tint hardly less aureate 

 than those evolved by arsenic, have not commonly, if at all, 

 been employed as hair-dyes. The theory of this process of 

 dyeing is identical with that already described under the head 

 of dyeing black by lead compounds. The sulphuretted hy- 

 drogen evolved reacts upon arsenic and cadmium, producing 

 yellow, whereas it would have evolved black with a lead com- 

 pound ; in this is all the difference. Evidently this process is 



