ITS CHEMICAL RELATIONS. 



57 



detects even still less alteration in whalebone or tortoise-shell that 

 has been acted upon by this acid, although the former is converted 

 into a gelatinous substance when boiled with the concentrated acid. 



The epidermis very rapidly swells in concentrated sulphuric 

 acidy exhibiting vesicular cells which become even more distended 

 on the addition of water. The cells of the rete mucosum remain 

 unchanged in cold sulphuric acid, but when boiled they are com- 

 pletely dissolved. 



Concentrated sulphuric acid acts very slowly on the substance 

 of the nails, button the application of heat it brings into view, in 

 the course of a few minutes, flat, polygonal cells, some of which 

 are provided with nuclei. 



It is only after the prolonged action of concentrated sulphuric 

 acid for many hours that cows 5 horn gradually resolves itself into 

 cells. 



Whalebone is gradually converted, by this acid, into a mucous 

 mass, in which the cell-membranes may be distinctly recognised. 



Sulphuric acid exerts an equally inefficient action on tortoise- 

 shell, and it is only after prolonged soaking or boiling with concen- 

 trated acid that cells can be detected in the gelatinously swollen 

 mass ; but even these are not isolated. 



Concentrated nitric acid imparts a yellow colour to most horny 

 tissues, and isolates the cells of some, without, however, bringing 

 them distinctly into view. 



These tissues have, as we already observed, been subjected to 

 elementary analyses, after having been previously treated with 

 alcohol and ether. In order to exhibit the analogy of their com- 

 position, we subjoin the empirical results obtained from the ana- 

 lyses of Scherer,* Mulder, Tilanus,f and van Kerckhoff.J 



* Ann. d. Ch. u. Pharm. Bd. 40, S. 1-45. 

 t Scheik. Onderz. D. 3. 

 + Ibid. 



