The fats of nuts, their leading food principle, are the most digestible of all forms of fat. Having a high melting point, they are far more digestible than animal fats of any sort. The indigestibility of beef and mutton fat has long been recognized. The fat of nuts much more closely resembles human fat than do fats of the sort mentioned. The importance of this will be appreciated when attention is called to the fact that fats entering the body do not undergo the transformation changes which take place in other foodstuffs; for example, protein in the process of digestion is broken into its ultimate molecular units. Starch is transformed into sugar, which serves as fuel to the body, but fats are so slightly modified in the process of digestion and absorption that after reaching the blood and the tissues they are reconstructed into the original form in which they are eaten; that is, beef fat is deposited in the tissues as beef fat without undergoing any chemical change whatever; mutton fat is deposited as mutton fat; lard as pig fat, etc. When the body makes its own fat from starch and sugar, the natural source of this tissue element, the product formed is _sui generis_ and must be better adapted to the body uses than the animal fat which was _sui generis_ to a pig, a sheep, or a goat. It is certainly a pleasant thought that one who rounds out his figure with the luscious fatness of nuts may felicitate himself upon the fact that his tissues are participating in the sweetness of the nut rather than the relics of the sty and the shambles. It is true that nuts are poor in carbohydrates; that is, they contain no starch and little sugar, but this deficiency can be easily supplied by fruits, as will be readily seen by reference to Table V. Of the three great food principles required for human nutrition, protein, fats, and carbohydrates, the nut supplies two--protein and fats in rich abundance, and of very finest quality. The amount of protein found in fruits with very few exceptions is so small as to be insignificant; fats are practically wholly absent from fruits, while sugar and dextrine are abundant. Fruits are thus the natural complement of nuts.