Water, 890 858 Solids, 110 142 ---- ---- 1000 1000 Caseine, 35 68 Butter, 25 38 Sugar (with extracts), 48 30 Salts, 2 6 --- --- 110 142 Carb. Hyd. Nit. Oxy. Sulph. R (unknown). Caseine, 72 112 18 23 1 2 In milk, it will be seen from the preceding table, the albuminous group of aliments is represented by the caseine, the oleaginous by the butter, the aqueous by the water, the saccharine by the sugar of milk. Let us compare the composition of these four organic substances and water: Oxy. Hyd. Carb. Nitr. Sulph. R (unknown element). Water, 1 2 Sugar, OH2+ 11 22 12 Caseine, 23 112 72 18 1 2 Olein, 6 38 21 Among the salts of milk are phosphate of lime, alkaline and other salts, and a trace of iron; so that it may be briefly said to include all the substances which the tissues of a growing animal need for their nutrition and which are required for the production of animal heat. The yolk and albumen of eggs stand in the same relation as food for the embryos of oviparous animals, that milk does to the young mammalia; and affords another example of mixed food being provided as the most perfect nutrition. The composition of fowl's egg is: White. Yolk. Water, 80.0 53.73 Albumen, 15.5 17.47 Mucus, 4.5 yellow oil 28.75 Salts, 4.0 6.0 The food substances. 1. Amyloids, starch and sugars. Starch is derived from grain and vegetables, as wheat, barley, rye, oats, corn, rice, sago, tapioca, beans, peas, etc. The vegetables contain from 75 to 90 per cent of water. Starch and sugars are derived from such as potatoes, turnips, carrots, beets, etc., etc. The fruits are largely composed of water, sugars, and acids. All these classes of food contain only three elements.--Starch: Carbon. Hydrogen. Oxygen. 18 30 15 In their composition we have fifteen molecules of water presented carrying eighteen atoms of carbon. Sugar: Carbon. Hydrogen. Oxygen. 12 22 11