FATS. 419 



also be preserved by soaking them in alum and after- 

 ward in oil. Soft chamois' leather is prepared by 

 working the skin with fat alone. 



FATS. 



1043. COMPOSITION. We have already 



What is said * 



of the consti- seen that there are both acids and bases of 

 tutton of fats? p ure iy organic origin, and that these may 

 combine like the similar compounds of inorganic chem- 

 istry, to form salts. The animal fats and oils are mix- 

 tures of such compounds in different proportions. The 

 principal of these organic salts are stearine, margarine, 

 and oleine. Stearine is solid, oleine fluid, and marga- 

 rine occupies a middle position between the two. The 

 difference of consistence in butter, lard, and tallow, 

 is owing to varied proportions of these three substances 

 which enter into their composition. Beside the fats 

 contained in other parts of the body, the brain and 

 nerves of animals contain, with albumen and water, 

 certain peculiar acids and fats. 



1044. SEPARATION OF FATS IN OIL. 



How may the . IT- / 



constituents of The steariiie and oleine of whale oil sep- 

 rated? Cpa ' arate spontaneously in cold weather. The 

 cold which i sufficient to harden the for- 

 mer, leaves the latter in a fluid condition. This effect 

 is often observed in lamps during winter weather. The 

 case is quite analogous to the separation of cider into 

 alcohol and water, by freezing. The water congeals, 

 and leaves the alcohol fluid. Both separations are im- 

 perfect. As the alcohol produced by the above process 



