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VEGETABLE FOOD. 
Food yielding fat and oil is supplied by both the vegetable and animal 
kingdoms. The distinguishing feature of the following articles of food 
is the oil they contain : 
OLEAGINOUS FOOD. 
Under the names of oil, butter, fat, lard, suet, grease, a substance is 
used largely as an article of food, which differs chemically from starch 
and sugar in the small quantities of oxygen gas it contains. The 
composition of these oleaginous substances may be represented 
generally as follows : — Carbon eleven parts, hydrogen ten parts, oxygen 
one part. 
Oil differs from the other carbonaceous substances in food in not 
only supplying materials for maintaining animal heat, but in forming a 
part of the tissues of the body called fat. 
Its action as a heat-giver is greater than starch or sugar, as it 
supplies hydrogen as well as carbon for burning in contact with 
oxygen. Its power as a heat-giver compared with these is as two-and-a- 
half to one. It is very generally present in both animal and vegetable 
food. The action of oil on the system is not, however, confined to its 
heat-giving powers. It seems essential to the development of the fleshy 
part of the body. Hence it is found present in the eggs of animals. 
Fish-oil is given in those diseases where a wasting of the flesh is 
present, as in consumption. 
The animal system has the power of converting starch and sugar 
into fat. All ruminant and hybernating animals become fat in the 
summer and autumn. The fat thus accumulated is consumed during 
the winter in maintaining the heat of the body. Man to some extent 
obeys the same law, and weighs more during the summer than the 
winter months. 
Oils vary in their chemical composition and physical properties. 
Many vegetable oils, as cocoa-nut and olive oil, contain two principles 
one of which is liquid, and remains so at all ordinary temperatures ; 
the other is solid when the temperature falls below 40 degrees. The 
former is called Oleine, and the latter Stearine. Fats, lards, and butters 
are composed of the latter, or -of principles having the same property. 
Oleine, stearine, and other fatty pririciples consist of acids combined 
with a base. This base is called Glycerine, and is separated from oils in 
the process of soap -making. 
The principal source of oil used as food from the vegetable kingdom 
is the olive (Olea Europea). The seeds of most plants contain oil in 
addition to starch and other matters. The seeds of the palm tribe 
contain much oil as the cocoa-nut palm (Cocus micifera). So also do 
the seeds of the cocoa or chocolate plant (Theolroma cacao). 
