Diges´ter, a strong vessel of copper or iron, on which is screwed an air-tight cover with a safety-valve, the object being to prevent loss of heat by evaporation, and to enable boiling to take place at a high pressure. Water may be thus heated to 400°F.; at which temperature its solvent power is so greatly increased that bones are converted into a jelly.
Diges´tion is that process in the animal body by which the aliments are so acted upon that the nutritive parts are prepared to enter the circulation, and separated from those which cannot afford nourishment to the body. The organs effecting this process are called the digestive organs, and consist of the stomach, the great and small intestines, &c. (see Intestine, Stomach), the liver, and pancreas. When the aliments, after being properly prepared and mixed with saliva by mastication, have reached the stomach, they are intimately united with a liquid substance called the gastric juice, by the motion of the stomach. By this motion the aliments are mechanically separated into their smallest parts, penetrated by the gastric juice, and transformed into a uniform pulpy or fluid mass. The gastric juice acts upon the albuminous parts of the food, converting them into peptones, which can pass through organic membranes and thus enter the blood. This
action is aided by the warmth of the stomach. The pulpy mass, called chyme, proceeds from the stomach, through the pylorus, into that part of the intestinal canal called the small intestine, where it is mixed with the pancreatic juice, bile, and intestinal juice. The pancreatic juice converts starch into sugar, albumins into peptones, and emulsionizes fats, so that all these kinds of food are rendered capable of absorption. The process is aided by the intestinal juice. The bile also acts upon fats, and thus the food is formed into the chyle, which is absorbed into the system by the capillary vessels called lacteals (see Chyle; Chyme), while the non-nutritious matters pass down the intestinal canal and are carried off.—Bibliography: F. Hare, Food Factor in Disease; Taylor, Digestion and Metabolism.
Digit (dij´it; Lat. digitus, a finger), in arithmetic, any one of the ten numerals, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0. Digit is also a measure of a finger's breadth, equal to ¾ inch.
Digit, in astronomy, is the measure by which we estimate the quantity of an eclipse. The diameter of the sun or moon's disk is conceived to be divided into twelve equal parts, called digits; and according to the number of those parts or digits which are obscured, so many digits are said to be eclipsed.
Digitalin (dij-i-tā´lin), a vegetable alkaloid, the active principle of the Digitālis purpurĕa or foxglove. It has a bitter taste, and is a strong poison, but is used medicinally, especially for the heart. See next article.
Digita´lis (dij-), a genus of plants, nat. ord. Scrophulariaceæ, containing about twenty species of tall herbs, natives of Europe and Western Asia. The purple foxglove (D. purpurĕa) is a common wild flower in Britain, and several species are grown in gardens. Various preparations from the foxglove receive this name, and are used in medicine, principally in cases of heart disease.
Digitigra´da (digitus, finger, toe, and gradi, to walk), a section of the Carnivora, so called from their walking on the ends of their toes; as the dog, cat, and their allies. See Plantigrade.
Digito´rium, a small portable dumb instrument having a short keyboard with five keys like those of a piano, used by piano-players for practice, to give strength and flexibility to the fingers.
Digne (dēny), a town, France, capital of the department of Basses-Alpes, picturesquely situated on a mountain slope, 60 miles north-east of Marseilles. In 1629 a plague reduced the population from 20,000 to 1500. Pop. 7317.