OSr HUMAN HAIX. ' 143 



lleiJ hair leaves a yeilowisb red residuum, in which are red hair a red. 

 found a great deal of oil, sulphur, and a little iron. 



The solutions, when they hare been filtered, haye Action of rc- 

 scarcely any colour : concentrated acids render them tur- g^^^jj^" 

 bid ; but an excess of these reagents restore their former 

 ti-ansparency, and weak acids produce no change in them. 

 The infusion of galls and oxigenated muriatic acid form 

 m them copious precipitates. Silver is blackened in them^ 

 and the acetate of lead is precipitated brown. These 

 solutions, evaporated with all due precaution, did not 

 assume the consistence of jelly on cooling, but remained 

 glutinous ; whence I concluded, that ihe substance of 

 hair is not of a gelatinous nature. 



The acids form more copious and deeper coloured pre- 

 cipitates in Hie solutions of hair effected at a higher tem- 

 perature, an consequence of their decomposing an ammo- 

 niacal soap, which does not take place in the former 

 case. 



I have likewise dissolTed hair, both black and red, in Solution in 

 water containing merely 4 per cent, of caustic potash. ^^*^ lixivium. 

 During this solution hidxosulphure of ammonia is evolved, 

 which seems to announce an incipient decomposition of 

 the black hair, leaving a black re&idoum composed of a 

 thick oil, still a little animalized, with iron and sulphur. 

 After the solution of the red hair, a yellow oil containing 

 sulphur and a few atoms of iron remains. 



In these solutions acids form white precipitates^ soluble Action of adds 

 in an excess of ihe acids. When these precipitates are ®" '** 

 thus redissolved in acids, at the expiration of a certain 

 time an oil appears on the surface in the form of a pellicle 

 with the prismatic colonic. 



The solution of hair in potash precipitates lead of a Qf 1^,4. 

 black hue on account of the hidrosulphuret it contains. 

 That of the red hair appears to contain most. When it 

 has been freed from sulphur by exposure to the air, it 

 has only a smell of soapsuds, like which it becomes 

 mouldy. 



Each of the acids acts in a particular manner on hair. Effects of the 

 The sulphuric and muriatic acids assume at first a fine different acids, 

 rose colour, and afterward dissolve the hair. The nitric 

 acid turns hair yellow, and likewise dissolves it by means 



of 



