232 PARTS OF ANIMALS. 



lute acids from its solution, and which are again redissolved by 

 an excess of the acids. It is distinguished from albumen by the 

 precipitates produced by acetic acid and muriatic acid in its 

 aqueous solutions, and from casein, because prussiate of potash 

 does not precipitate its acid solutions. 



A concentrated solution of pepsin is thrown down by corrosive 

 sublimate and acetate of lead, but the precipitates are redissolved 

 by adding an excess of the reagent, and also by acetic and mu- 

 riatic acids. The sulphates of iron and the protochloride of tin 

 also precipitate pepsin ; and all the precipitates by metallic solu- 

 tions possess digestive properties. 



When burning, pepsin gives out the odour of burning horn, 

 and leaves a charcoal difficult to incinerate, in which is found 

 lime, soda, phosphoric acid, and a little iron. 



CHAPTER VII. 



QF PANCREATIN. 



THIS substance was detected in the pancreatic juice of the 

 dog by Tiedemann and L. Gmelin, but they did not obtain it in 

 a separate state. The only characteristic property of it which 

 they ascertained is this : it is coloured red by a small quantity 

 of chlorine, and discoloured by a small quantity. 



DIVISION II. 



OF THE PARTS OF ANIMALS. 



THE different substances which compose the bodies of animals 

 may be divided into two classes, namely, 1st, the solid parts, such 

 as bones, muscles, skin, &c. of which their bodies are made up ; 

 2d, the fluid parts. Some of these, as the chyle and blood, are 

 intended for the nourishment of the living being ; others, as sa- 



