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Biochemical studies of the diet
820
CURRENT TOPICS.
[J. F. I.
Biochemical Studies of the Diet.-In a paper on the relation of the diet to pellagra, E. V. MCCOLLUM (Proceedings of the American Philosophical Society, 1919, vol. aviii, pp. 41-54) gives a summary of recent biochemical discoveries concerning a satisfactory diet. The diet must furnish s,ufficient energy in the form of carbohydrates, fats and proteins, an adequate supply of mineral food or ash in suitable combinations, and a sufficient amount of the two food hormones, or vitamines fat-soluble A and watersoluble B. The proteins must be suitable in both quality and quantity; quantitatively the ration should contain a liberal amount of protein; qualitatively the value of a protein depends on its source, those of the navy bean or pea are less valuable than those of the cereal grains, and these in turn less valuable than those of milk. The food hormones are dietary essentials, as yet unidentified chemically; absence of fat-soluble A from the diet produces a dis,eased condition of the eye known as xerophthalmia, while absence of water-soluble B gives rise to the disease beri-beri. A satisfactory diet cannot be obtained from mixtures of seeds or products obtained by their milling with tubers, edible roots, and cuts of meat consisting of ‘muscle ; in addition one or more of the protective foods must be eaten. The group of protective foods includes milk, eggs, and leafy vegetables; by virtue of their inorganic content of fat-soluble A, and the quality of their proteins, they insure the presence of a sufficient amount of these ingredients in the diet if they be used in sufficient quantity; they thereby protect the health, hence their name protective foods. If foodstuff or mixture of foodstuffs may be analyzed by the biological method, it is fed to a group of animals, s.uch as rats, while other groups receive it supplemented by pure protein, or salts, or a food hormone, etc., the influence of the various rations on the weight and health of the experimental animals is then observed. Pellagra is caused by an infectious agent. and not by a faulty diet, however such a diet may increase the susceptibility to J. S. H. this disease. Steel Disk Automobile Wheels. (Scientijic American, vol. cxxi, is a growing tendency on the p. 225, September 6, IgIg.)-There part of motorists to favor the pressed steel disk wheel and increasing numbers of fine cars are being equipped with traction and support members of this type. The wheel used for passenger cars is a single disk type, being dished for strength. In most designs the thickness of the metal is greater at the centre than at the rim, thus proportioning the section to the &rain coming upon it. A cast-steel master hub is fastened to the axle, and the steel disk is attached to this by four easily removable nuts which screw on studs in the permanent hub flange. The disk wheel is as easily removed as any other type and is stronger and more easily washed than the conventional wood or wire spoked forms.
CURRENT TOPICS.
[J. F. I.
Biochemical Studies of the Diet.-In a paper on the relation of the diet to pellagra, E. V. MCCOLLUM (Proceedings of the American Philosophical Society, 1919, vol. aviii, pp. 41-54) gives a summary of recent biochemical discoveries concerning a satisfactory diet. The diet must furnish s,ufficient energy in the form of carbohydrates, fats and proteins, an adequate supply of mineral food or ash in suitable combinations, and a sufficient amount of the two food hormones, or vitamines fat-soluble A and watersoluble B. The proteins must be suitable in both quality and quantity; quantitatively the ration should contain a liberal amount of protein; qualitatively the value of a protein depends on its source, those of the navy bean or pea are less valuable than those of the cereal grains, and these in turn less valuable than those of milk. The food hormones are dietary essentials, as yet unidentified chemically; absence of fat-soluble A from the diet produces a dis,eased condition of the eye known as xerophthalmia, while absence of water-soluble B gives rise to the disease beri-beri. A satisfactory diet cannot be obtained from mixtures of seeds or products obtained by their milling with tubers, edible roots, and cuts of meat consisting of ‘muscle ; in addition one or more of the protective foods must be eaten. The group of protective foods includes milk, eggs, and leafy vegetables; by virtue of their inorganic content of fat-soluble A, and the quality of their proteins, they insure the presence of a sufficient amount of these ingredients in the diet if they be used in sufficient quantity; they thereby protect the health, hence their name protective foods. If foodstuff or mixture of foodstuffs may be analyzed by the biological method, it is fed to a group of animals, s.uch as rats, while other groups receive it supplemented by pure protein, or salts, or a food hormone, etc., the influence of the various rations on the weight and health of the experimental animals is then observed. Pellagra is caused by an infectious agent. and not by a faulty diet, however such a diet may increase the susceptibility to J. S. H. this disease. Steel Disk Automobile Wheels. (Scientijic American, vol. cxxi, is a growing tendency on the p. 225, September 6, IgIg.)-There part of motorists to favor the pressed steel disk wheel and increasing numbers of fine cars are being equipped with traction and support members of this type. The wheel used for passenger cars is a single disk type, being dished for strength. In most designs the thickness of the metal is greater at the centre than at the rim, thus proportioning the section to the &rain coming upon it. A cast-steel master hub is fastened to the axle, and the steel disk is attached to this by four easily removable nuts which screw on studs in the permanent hub flange. The disk wheel is as easily removed as any other type and is stronger and more easily washed than the conventional wood or wire spoked forms.