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Effects of Food Upon Man

genized or non-azotized articles; and, 2nd, nitrogenized or azotizedthe terms nitrogenized and azotized meaning one and the same thing, whilst the term protein compound, which is commonly confounded with them, is by physiologists confined to that exact condition or proportion of nitrogen with carbon, oxygen, and hydrogen, which is capable of being converted into albumen, fibrine, or casein, in the process of digestion. 4. THE AZOTIZED COMPOUNDS are required for the repair of the muscular tissue, and for the nutrition of the body generally, and consequently a proper amount of them must be obtained, or the machine will not be maintained in a state of health, nor will it be kept alive without a certain proportion of them. The list of azotized articles of food includes not only many animal substances, as albumen, fibrine, casein, &c., but also some few vegetables, such as the grains of corn, the seeds of leguminous plants, cabbages, mushrooms, &c. As a consequence, therefore, of their containing nitrogen, all these are specially calculated to support the muscular powers, and to keep up the supplies necessary for the general nutrition of the body; and, in whatever form they are introduced into the stomach, they are capable of being converted into the particular material required. So that, by the aid of the digestive powers, wheaten bread is as capable of forming muscle as flesh itself, containing in fact a vegetable albumen identical in composition with that of the animal kingdom. But some other azotized materials are not found already elaborated in the vegetable kingdom-as, for instance, gelatine; and though this may be manufactured in the animal economy out of vegetable substances, yet there is reason to believe that if it is presented to the stomach ready formed, it is more easily applied to the purposes of nutrition; and consequently gelatine, or, in common language, jelly, is a very valuable aid to the food of weakly or invalid persons, though it is ascertained by experiment that by itself it will not support life. It is also doubly useful in this state, because it is at once absorbed by endosmose from the lining of the stomach and intestines without any necessity for the process of digestion and assimilation-an act which, of itself, requires an expenditure of vital power. 5. THE NON-AZOTIZED COMPOUNDS, used as food, are met with in great abundance in the vegetable kingdom, though there are few vegetables which, in their natural state, are wholly deprived of nitrogen. But the manufactured articles of food commonly known as arrowroot. sugar, oil, and some others, are composed of carbon, hydrogen, and oxygen alone, and are chiefly used in supporting the respiratory process, and thus maintaining the temperature of the body. Among the compounds known as sugar and starch, the amount of oxygen is only sufficient to form water by its union with the hydrogen contained in them, and thus the carbon is at liberty to combine with the oxygen introduced through the lungs, forming carbonic acid, and giving out heat. Again, in the oily matters used as food, the proportion of oxygen is so small that they contain a large surplus of hydrogen as well as carbon, ready to be burned off in the system by union with oxygen obtained from the air. It is generally believed that the most simple of these non-azotized compounds, as sugar and starch, are carried off by the respiratory process within a very short time after they are introduced into the system; while the oily matters, which are taken up by the lacteals, and require a greater amount of assimilative power, are not so readily brought into use, though quite as efficacious when properly prepared. When the amount of respiratory or nonazotized matter is too small for the heat-producing office, a larger amount of azotized materials must be employed to supply its place, in which there is a great waste. Thus, supposing 100 grains of oil to develop a certain amount of heat, then, in order to accomplish the same effect, 240 grains of starch must be used, or 249 grains of canesugar, 263 grains of grape-sugar, 266 grains of proof spirit, and 770 grains of fresh lean meat. Alcohol belongs to the respiratory class, and, if properly diluted, it may be rendered very serviceable when there is a deficiency of heat-producing material, or when the surrounding air is so cold as to call for an extra supply. But if employed in hot climates, or in addition to food already abounding in carbon and hydrogen, it is injurious, from its affording more of these elements than is wanted by the system. 6. IT IS THUS CLEAR that in man, as well as in all other warm. blooded animals but the carnivorous tribes, a mixture of azotized and non-azotized substances is required for his support. Nature has taught him to supply the wants of his system in the most complete manner, as far as general principles are concerned; and all that art can do is to direct him in his search for those particular articles of food which are most readily obtained, or most easily digested and assimilated to his own wants. No substance is more extensively used than bread, either made of wheat, Indian corn, or rye; and there is none met with throughout the world, upon which alone man can subsist for any length of time without injury to health, excepting, perhaps, oatmeal porridge, which indeed so closely resembles bread in its composition as to be almost identical with it; and milk, which is still more adapted to support life, but is chiefly intended for young animals by nature. With the addition of a moderate quantity of butter, the heatproducing power of bread is rendered quite sufficient to meet the wants of even our coldest winters; while, for the purpose of affording additional muscular support, flesh, albumen, or milk containing casein, must be supplied, together with gelatine in the shape of soups or jellies. But when bread forms a principal article of diet, unless the individual is taking a great amount of exercise, the regular use of meat in large quantities should be cautiously indulged in, being disadvantageous both to the pocket and to the health. On the other hand, when rice, potatoes, or any other vegetable substances, almost wholly free from nitrogen, are the chief articles of diet, either, an enormous bulk must be digested in order to obtain a sufficient supply of nitrogen, and to the great waste of the carbon and hydrogen, or else some material containing a large proportion of nitrogen must be added, such as eggs, milk, or flesh. Lastly, the oily kinds of food are chiefly adapted for those who live in very cold climates, and require an extra supply of heat, and who are consequently led to devour train-oil with the greatest avidity. It is said that the Esquimaux will devour thirty pounds of blubber at a meal, and, as it is slowly digested, they are enabled to go for several days without another supply, and in the interval to keep up a temperature equal to their wants when exposed to their severe climate. 7. THE RELATIVE PROPORTIONS of azotized and non-azotized substances in our ordinary articles of food are here appended, on the authority of Liebig; the non-azotized being calculated as starch :- Article of Azotized or Blood-making Non-azotized or Respiratory Food.