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 DIEDENHOFE N —D IETETICS preacher in favour of a reconciliation between philosophy and science. In 1871 his fame had so much grown that he was chosen to deliver the funeral oration over the murdered archbishop of Paris, Monseigneur Darboy. After this he delivered some discourses at the Church of St Jean de Beauvais in Paris on the relations between science and religion ; but his utterances, especially on the question of divorce, were deemed suspicious by those in authority, and his intimacy with Claude Bernard the physiologist was disapproved. He was interdicted from preaching and sent into retirement at the Convent of Corbara in Corsica. After eighteen months he emerged, and travelled in Germany, publishing an interesting work upon that country, entitled Les Allemands, on his return to France. In 1890 he produced his best-known work, a Life of Jesus (Jesus-Christ), for which he had qualified himself by travel in the Holy Land. In the same year he became director of the College Albert-le-Grand (Albertus Magnus) at Arcueil, and himself founded three auxiliary institutions, Ecole Lacordaire, ificole Laplace, and Ecole St Dominique. He wrote, in addition, several works on educational questions, and augmented his fame as an eloquent preacher by discourses preached during Lent and Advent. He died in 1900. (j. J. L*.) Diedenhofen (in French, Thionville), a fortified town of Germany, in Alsace-Lorraine, dist. Lorraine, on the Moselle, 22 miles north from Metz by rail, a railway junction of some consequence, with cultivation of wine, fruit, and vegetables, brewing, tanning, &c. It is an ancient Frank town (Theudonevilla, Totonisvilla), in which imperial diets were held in the 8th century ; was captured by Conde in 1643 and fortified by Yauban ; capitulated to the Prussians in 1870. Population (1885), 8111 ; (1900), 10,062. Dieppe, chief town of arrondissement, department of Seine Inferieure, France, 35 miles north of Itouen, with terminal station on railway from Paris. The Palais de Justice is a recent erection. Lace, woollen goods, and ceramic wares are now important manufactures. The ivory carving has greatly declined in recent years, and instead of 300 in 1866 only about 40 workmen were employed in it in 1898. Efforts are being made, however, to give a fresh impetus to this industry. In 1900, 1894 vessels of 497,446 tons entered and cleared, of which Great Britain’s share was 340,082 tons. Imports were valued (1899) at <£5,248,000; exports at £6,732,000. The principal imports were textiles (chiefly silk), forming 50 per cent. The principal exports were textiles (silk, cotton, and woollen), amounting to 40 per cent., and hides and skins. During the summer months large quantities of fruit are sent to England. The total port traffic on the Canal de Bourgoyne amounted to 94,774 tons in 1899. The number of vessels engaged in the fisheries in 1898 was 95, with 471 men. A school of fisheries, similar to that which has already rendered good service at Sables d’Olonne, has been established at Dieppe. A new harbour railway station and a landing stage were opened in 1900, and an esplanade mile in length is in course of construction. The passenger traffic with England was represented in 1900 by 130,985 arrivals from and 139,143 departures to that country. The harbour, to which an improved approach is projected, comprises an outer and an inner port, with a total length of quayage 3772 feet. Depth at high tide in the outer port (ordinary spring) varies in different parts from 29 to 36 feet. There are four floating docks and a dry dock. The entrance channel, cut in the bed of the Arques, is 1950 feet long and 246 feet wide. Population (1881), 20,408; (1901), 21,798.

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Dietetics.—The term dietetics is frequently applied to the science of the food and nutrition of man in health and disease. This article deals mainly with that part of the subject which has to do with the composition and nutritive values of foods and their adaptation to the use of people in health. The principal topics are:—1. Food and its functions. 2. Metabolism of matter and energy. 3. Digestibility and availability of food materials. 4. Fuelvalue of food. 5. Composition of food materials. 6. Food consumption—studies of dietaries. 7. Hygienic economy of food. 8. Quantities of nutrients needed. 9. Pecuniary economy of food. 1. Food and its Functions.—Food is that which, taken into the body, builds tissue or yields energy. More specifically, food supplies the wants of the body in several ways :— (1) it forms the tissues and fluids of the body ; (2) it repairs the waste of tissues; (3) it is stored in the body for future consumption ; (4) it is consumed as fuel, its potential energy being transformed into heat or muscular energy or other forms of energy required by the body; and (5) in being consumed, it protects tissue or other food from consumption. The most healthful food is that which is best fitted to the needs of the user. To be adapted to his needs, the food must supply the different nutritive ingredients, or nutrients, in the kinds and proportions required by the body for building and repair and for supplying energy. It should also be in forms which the person can easily digest and which will “ agree ” with him. The cheapest food is that which furnishes the most nutriment at the least cost. The most economical food is that which is most healthful and cheapest. Ordinary food materials, such as meat, fish, eggs, potatoes, wheat, &c., consist of—refuse, e.g., the bones of meat and fish, shells of shellfish, skin of potatoes, bran of wheat, &c.; edible portion, e.g., the flesh of meat and fish, the white and yolk of eggs, wheat flour, &c. The edible portion consists of water and nutritive ingredients or nutrients. The principal kinds of nutritive ingredients are protein, fats, carbohydrates, and mineral matters. The water, refuse (and salt of salted meat and fish), are here regarded as nonnutrients and, in comparing the values of different food materials for nourishment, are left out of account. The following are familiar examples of compounds of each of the four principal classes of nutrients :— Protein.—The term protein is here used to include the nitrogenous nutrients of foods except the nitrogenous fat, namely, the proteids, e.g., albumen (white of egg), casein (curd) of milk, myosin of muscle (lean meat), gluten of wheat, &c.; and the non-proteids, including the so-called extractives {e.g., creatin) of meats and the amides {e.g., asparagin),. and allied compounds of vegetables and fruits.1 Fats.—Fat of meat; fat (butter) of milk, olive oil, oil of corn, wheat, Ac. (Here are included the nitrogenized fats, as lecithin.) Carbohydrates.—Sugars, starches, cellulose (woody fibre),. &c. Mineral Matters.—Phosphates, sulphates, and chlorides of potassium, sodium, calcium, &c. Protein forms tissue (muscle, tendon, Ac.) and fat, and serves as fuel. Fats form fatty tissue (not muscle, Ac.)' and serve as fuel. Carbohydrates are transformed into fat and serve as fuel. All these nutrients yield energy in the form of heat and muscular power. In being themselves burned to yield energy, the nutrients protect each other from being consumed. The protein and fats of body tissue 1 Unfortunately the terms applied by different writers to thesenitrogenous compounds are very conflicting. In accordance with a common usage, preference is here given to the word protein to cover all the nitrogenous compounds except the nitrogenous fats, though the word proteid is sometimes used in this signification.