310 SOLID PARTS OF ANIMALS. 



may be reduced to powder with the greatest facility. The 

 aqueous solution of this substance is precipitated by the same re- 

 agents as the acetic solution of horn. But prussiate of potash 

 does not render it muddy unless acetic acid be previously added. 

 This substance is a compound of the horny matter and lime. 

 The lime remains behind when we burn the compound. Muri- 

 atic acid throws down a precipitate from its solution in water, 

 which is redissolved by the addition of a greater quantity of 

 acid. Acetic acid throws down a precipitate which requires for 

 solution a very large quantity of free acid. 



Jt is evident from these facts that when potash is made to act 

 upon horn, a decomposition takes place ; the horn being convert- 

 ed into carbonic acid, ammonia, sulphuretted hydrogen, and a 

 substance soluble in muriatic acid and water, with a minimum of 

 alkali ; while another portion of matter remains insoluble com- 

 bined with an excess of muriatic acid. 



Dr John, a great many years ago, made an analysis of the horns 

 of oxen. He extracted from them the following constituents : 



Indurated albumen, . . 90 



Gelatinous albumen with osmazome ? . 8 



Lactic acid, 



Lactate of potash, 



Sulphate, muriate, and phosphate of potash, 



Phosphate of lime, 



Oxide of iron, trace, 



Ammoniacal salt, . . J 



Fat, . . 1 



100* 



The quantity of earthy matter contained in horns is exceed- 

 ingly small. Mr Hatchett burnt 500 grains of ox horn. The 

 residuum was only 1.5 grain, and not the half of this was phos- 

 phate of lime. 78 grains of the horn of chamois left only 0-5 of 

 residue, of which less than the half was phosphate of lime.f They 

 consist chiefly of a membranous substance, which possesses the 

 properties of coagulated albumen ; and probably they contain also 

 a little gelatin. Hence we see the reason of the products that 

 are obtained when these substances are subjected to distillation. 

 Dr Scherer subjected the horn of the buffalo to a chemical 

 analysis.:]: It was purified by washing it with water and boiling 



* Annals of Philosophy, ix. 55. f Phil, trans. 1 799, p. 332. 



\ Ann. der Phtirm. xl. 56. 



