The Chemistry of Cookery

to the air is dehydrated. Fat is only dissociated as regards its glycerine, and is cooked thereby. The dietetic value of milk is obvious enough from the fact that the young of the human species and all the mammalia, whether carnivorous, graminivorous, or herbivorous, are entirely fed upon it during the period of their most rapid growth. This, however, does not justify the practice of describing milk as a model diet and tabulating its composition as that which should represent the composition of food for adults. The fallacy of this is evident from the fact that grass is the model food of the cow, and milk that of the calf. Although the grass contains all the constituents of the milk, their proportions are widely different; besides this the grass contains a very great deal of material that does not exist in milk—silica for example. The constituents of milk are first water, constituting from 65 to 90 per cent. Nitrogenous matter, consisting of the casein above described and a little albumen. Fat, sugar, and saline substances. The proportions of these vary so greatly in the milk from different animals of the same species, and in that from the same animal at different times that tabular statements of the percentage composition of the milk of different animals are very variable. I have five such tables before me, assembled for the purpose of supplying material for my readers, but they are so contradictory, though all by good chemists, that I am at a loss in making a choice. The following is Dr. Miller’s statement of the mean result of several analyses: +------------------------+-------+------+------+------+-------+-------+ | | Woman | Cow | Goat | Ass | Sheep | Bitch | +------------------------+-------+------+------+------+-------+-------+ | Water | 88·6 | 87·4 | 82·0 | 90·5 | 85·6 | 66·3 | | Fat | 2·6 | 4·0 | 4·5 | 1·4 | 4·5 | 14·8 | | Sugar and soluble salts| 4·9 | 5·0 | 4·5 | 6·4 | 4·2 | 2·9 | | Nitrogenous compounds }| | | | | | | | and insoluble salts }| 3·9 | 3·6 |