THE VOLATILE PART OF PLANTS. 91 
However greatly the various fats may differ in external 
characters, 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, 
thé first-named element being greatly preponderant. 
Stearin is represented by the formula C,, H,,,O, 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 solu- 
tion is obtained. Let cool slowly, when steurin will crystallize out in 
pearly scales. 
Palmitin, C,, H,, O,, 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,, H,,, O,, 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. Flaxseed oil 
contains linolein; castor oil, ricinolein, etc. 
We have already given the formule of the principal 
fats, but for our purposes, a better idea of their composi- 
tion may be gathered from a centesimal statement, viz. : 
* Margarin, formerly thought to be a distinct fat, is a mixture of stearin and 
palmitin. 
