The choice of food / by Henry Simpson.

  • Simpson, Henry.
Date:
[between 1870 and 1879?]
Catalogue details

Licence: Public Domain Mark

Credit: The choice of food / by Henry Simpson. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    withoti difficulty. You know by experience, most likely, that some things are apt to disagree, as it is said, while others give rise to no such trouble, but are easily borne by the stomach and readily digested. If we try to find a perfect food—one on which life can be sus- tained and growth take place—we must go to those which have been provided by nature. The young of many animals live for a longer or shorter period on the milk of the mother, which not only suffices for the maintenance of life, but also for growth. It must- therefore contain all the elements of nutrition within itself, and it may be taken as a sample of a food perfectly adapted to its purpose—namely, the nourishment of the young animal. When examined, it is found to contain nitrogenous matter, chiefly in the form of casein e, fatty matter with which we are familiar as butter, a carbo-hydrate called lactine, or sugar of milk, together with inorganic matter, as water and salines. The young of birds are formed out of the matters contained in the egg, which also repre- sents a food perfectly adapted to its purpose. The egg contains (i) nitrogenous matter, in the shape of albumen, both in the white and yolk; (2) oily matter in the yolk; (3) a trace only of carbo- hydrate in the fonn of a sugar, and in this it differs notably from milk; then there are (4) the inorganic matters, water and salts. The latter, however, are taken in part from the shelL This, as the process of hatching goes on, becomes gradually dissolved and absorbed by the growing chick. We may conclude, therefore, from the provision made by nature for the young mammalia—i.e., animals nourished at first on their mothers' milk—and for the young of birds, and also from the -universal practice of man, that our food must consist of these four ingredients, nitrogenous principles, non- nitrogenous principles, consisting of fats and carbo-hydrates, and of inorganic principles, namely, water and salines. NITROGENOUS FOODS. Although our bodies contain a large amount of nitrogen, it is always combined with other things, and is never free; and it is a curious fact, and one showing a beautiful adaptation to our needs, that though about four-fifths of the air around us consist of free nitrogen, it is not from that source we obtain it. In the atmo- sphere the nitrogen seems merely to dilute the oxygen, and to be without any marked character of its own. The oxygen would be too active by itself, and without the nitrogen we should burn away