THE VOLATILE PART OF PL^ NTS. 91 



However greatly the various fats may differ in external 

 o iracters, they are all mixtures of a few elementary fats. 

 The most abundant and commonly occurring fats, espe 

 cially those which are ingredients of the food of man and 

 domestic animals, viz. : tallow, olive oil, and butter, con 

 sist essentially of three substances, which we may briefly 

 notice. These elementary fats are Stearin, Palmitin, and 

 Olein* and they consist of carbon, oxygen, and hydrogen, 

 the first-named element being greatly preponderant. 



Stearin is represented by the formula C 57 H no O 8 . 

 is the most abundant ingredient of the common fats, and 

 exists in largest proportion in the harder kinds of tallow. 



it\ 

 IM 



EXP. 40. Heat mutton or beef tallow, in a bottle that may be tightly 

 corked, with tpc times its bulk of concentrated ether, until a clear solu 

 tion is obtain ju. Let cool slowly, when stearin will crystallize out in 

 pearly scales. 



Palnntill, C 61 H 98 O B , receives its name from the palm 

 oil, of Africa, in which it is a large ingredient. It 

 forms a good part of butter, and is one of the chief con 

 stituents of bees-wax, and of bayberry tallow. 



Olein, C 67 H 104 O 6 , is the liquid ingredient of fats, and 

 occurs most abundantly in the oils. It is prepared from 

 olive oil by cooling down to the freezing point, when the 

 stearin and palmitin solidify, leaving the olein still in the 

 liquid state. 



Other elementary fats, viz. : butyrin, laurin, myristin, etc., occur in 

 small quantity in butter, and in various vegetable oils. Fluxseed oil 

 certains liuolein; castor oil, ricinolein, etc. 



We have already given the formulae of the principal 

 Pats, but for our purposes, a better idea of their composi 

 tion may be gathered from a centesimal statement, viz. ; 



* Margarin, formerly thought to he a distinct fat, is a mixture of stearin and 

 jMtlmitln. 



