THE VOLATILE PART OF PLANTS. 85 



and Olein,* and they consist of carbon, oxygen, and hy- 

 drogen, the first-named element being greatly prepon- 

 derant. 



Stearin is represented by the formula C 57 H 110 6 . It 

 is the most abundant ingredient of the common fats, and 

 exists in largest proportion in the harder kinds of tallow. 



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

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

 solution is obtained. Let cool slowly, when stearin will crystallize out 

 in pearly scales. 



Palmitin, C 51 H 98 6 , 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 constituents 

 of beeswax, and of bayberry tallow. 



Olein, C 6 7H 1(H 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 the 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. Flaxseed oil 

 contains linolein ; castor oil, ricinolein, etc. 



We have already given the formulae of the principal 

 fats, but for our purposes, a better idea of their composi- 

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



CENTESIMAL COMPOSITION OF THE ELEMENTARY FATS. 



Stearin. Palmitin. Olein. 



Carbon 76.6 75.9 77.4 



Hydrogen 12.4 12.2 11.8 



Oxygen 10.0 11.9 10.8 



100.0 100.0 100.0 



Saponification. The fats are characterized by forming 

 soaps when heated with strong potash or soda-lye. They 

 are by this means decomposed, and give rise to fatty 



* Marffarin, formerly thought to be a chemically-distinct fat, is a mix- 

 ture of stearin and palmitin. Oleomargarine is the commercial designa- 

 tion of an artificially-obtained mixture of fats, animal or vegetable, 

 that has nearly the consistence of dairy buttei. 



