304 SOLID PARTS OF ANIMALS. 



The colouring matter of hair appears from Vauquelin's expe- 

 riments to be an oil. The oil is blackish-green in black hair, red 

 in red hair, and white in white hair. Vauquelin supposes that 

 sulphuretted iron contributes to the colour of dark hair ; and as- 

 cribes to the presence of an excess of sulphur the property which 

 white and red hair have of becoming black with the oxides of 

 the white metals. The sudden change of colour in hair from 

 grief, he thinks, is owing to the evolution of an acid.* 



Vauquelin considers the animal matter of which hair is chiefly 

 composed as a variety of inspissated mucus ; but some of its pro- 

 perties, especially its copious precipitation by tannin, do not well 

 agree with that supposition. It seems to approach more closely 

 to coagulated albumen, as Hatchett has shown. 



When hair is heated it melts, swells up, and gives out the 

 odour of burning horn. It burns with a strong flame, giving 

 out a great deal of smoke, and leaves a bulky charcoal. When 

 distilled per se, it gives one-fourth of its weight of empyreumatic 

 oil, water holding ammonia in solution and much inflammable 

 gas escapes, in which the smell of sulphuretted hydrogen may 

 be recognized. The charcoal remaining amounts to about one- 

 fourth of the weight of the hair. Different metalline salts pro- 

 duce the same change of colour on white hair as they do upon 

 the cuticle. We can dye white hair black by a solution of ni- 

 trate of silver in ether. But the best way of effecting that ob- 

 ject is to triturate the nitrate of silver with slacked lime, and to 

 make it up into a paste with hog's lard, which may be applied to 

 the hair without touching and blackening the skin. Another 

 substance commonly used to dye white hair black is protoxide of 

 lead in fine powder. One part of it is triturated with four parts 

 of slacked lime, and a weak solution of potash. A compound 

 of oxide of lead and potash is formed, which gradually penetrates 

 the hair, and sulphuret of lead is formed, which tinges the hair 

 black. 



Dr Scherer subjected the hair of the beard to a chemical ana- 

 lysis.f It was first washed with water, and then boiled in alco- 

 hol and ether. Thus prepared, it left when burnt O72 per cent 

 of ashes. Its constituents were 



* Nicholson's Journ. xv. 141, f Ann. der Pharm. xl. 55. 



