CHAPTER LXII.
1204. What are vegetable oils and fats?
Vegetable oils and fats constitute, next to starch and sugar, the most important secretion of the vegetable creation. There are very few plants from which some amount of oil cannot be obtained; and those which are famed for yielding it owe their celebrity rather to the abundance that they yield, and the peculiar qualities of their oil, than to the secretion of oil being rare—for probably there is no plant without it.
Oil is most commonly found in seeds, as rape-seed, linseed, &c., but it is found also in leaves, as in the rose, sweet-briar, peppermint, &c., where its presence may be recognised by the distinguishing perfume; and it is also found in the wood of a few trees, such as the sassafras and the sandal-wood; the bark frequently yields an oily secretion.
"Ointment and perfume rejoice the heart; so doth the sweetness of a man's friend by hearty counsel."—Proverbs xxvii.
The London and North Western Railway Company alone use about 50,000 gallons of oil yearly.
1205. Why are fat and oil found most abundantly in the bodies of animals in cold climates?