Fig. 65. An ideal view of the organs of digestion, opened nearly the whole length. 1, The upper jaw. 2, The lower jaw. 3, The tongue. 4, The roof of the mouth. 5, The œsophagus. 6, The trachea. 7, The parotid gland. 8, The sublingual gland. 9, The stomach. 10, 10, The liver. 11, The gall-cyst. 12, The duct that conveys the bile to the duodenum, (13, 13.) 14, The pancreas. 15, 15, 15, 15, The small intestine. 16, The opening of the small intestine into the large intestine. 17, 18, 19, 20, The large intestine. 21, The spleen. 22, The upper part of the spinal column.
CHAPTER XV.
HYGIENE OF THE DIGESTIVE ORGANS.
273. It is a law of the system, that each organ is excited to healthy and efficient action, when influenced by its appropriate stimulus. Accordingly, nutrient food, that is adapted to the wants of the system, imparts a healthy stimulation to the salivary glands during the process of mastication. The food that is well masticated, and has blended with it a proper amount of saliva, will induce a healthy action in the stomach. Well-prepared chyme is the natural stimulus of the duodenum, liver, and pancreas; pure chyle is the appropriate excitant of the lacteal vessels.
274. The perfection of the digestive process, as well as the health of the general system, requires the observance of certain conditions. These will be considered under four heads:—1st. The Quantity of food that should be taken. 2d. Its Quality. 3d. The Manner in which it should be taken. 4th. The Condition of the system when food is taken.
275. The QUANTITY of food necessary for the system varies. Age, occupation, temperament, temperature, habits, amount of clothing, health and disease are among the circumstances which produce the variation.
273–330. Give the hygiene of the digestive organs. 273. Give a law of the system. What is the appropriate stimulus of the salivary glands during mastication? Of the stomach? Of the duodenum? Of the lacteal vessels? 274. What does the perfection of the digestive organs require? 275. What exert an influence on the quantity of food necessary for the system?
276. The child and youth require food to promote the 130 growth of the different parts of the body. The more rapid the growth of the child, the greater the demand for food. This accounts for the keen appetite and vigorous digestion in childhood. When the youth has attained his full growth, this necessity for nutriment ceases; after this period of life, if the same amount of food is taken, and there is no increase of labor or exertion, the digestive apparatus will become diseased, and the vigor of the whole system diminished.