BOTANIC MATERIA MEDICA, 337 
inous nature; the liquid portion is termed olein, 
and the solid or concrete portions are called 
stearin and palmitin. The former substance 
predominates in the animal oil or fat, and the 
latter in the vegetable oils, although they may 
both exist in the same fat or oil. Thus oleinis 
the liquid principle of all fats, though it is dif- 
ficult to obtain in a pure state; palmitin or pal- 
mitic acid, is found in the semi-liquid fats, such 
as cocoanut oil, butter, palm oil, etc.; whilst 
stearin is abundantly found in animal fats. 
There are also many other principles beside the 
above mentioned existing in the fixed oils and 
waxes, such as butyrin, caprin, etc., the whole 
of which are termed by chemists glycerides, 
and further designated by them as salts or 
ethers of the triatomic alcohol glycerine, C,H, 
(OH,). For further information I refer you to 
the Dispensatory, page 905; 17th ed., or to 
some modern work on chemistry. The specific 
gravity of the fixed oils is less than that of wa- 
ter, the exceptions being some of the solid fatty 
substances found and incorporated with them, 
and termed Oils. The fixed oils, with buta 
few exceptions, are insoluble in alcohol and 
universally leave a greasy stain upon bibulous 
paper. They are particularly subject to rancidity 
and should therefore be kept in well closed 
vessels. 
