Intestinal digestion is not completed and the body does not receive its pabulum until the products of digestion have reached the liver and the thoracic duct.
ETIOLOGY.—It is usually said that intestinal dyspepsia is more common in women than in men, but the contrary is the rule. Some of its most common causes—over-eating and the eating of indigestible food—are especially vices of men.
It is more frequent between the ages of forty and fifty, but no age is exempt. Infants at the breast, children of any age, adults, and old men and women are alike subject to it. Men in middle life begin to suffer from the imprudence and carelessness of youth and from the anxiety and cares of business. The indulged children of rich parents and improperly bottle-fed infants frequently suffer.
Heredity and idiosyncrasy have a certain influence in determining the prevalence of intestinal dyspepsia. The distaste for and inability to digest vegetables, fruits, and fats are often peculiarities of family history. The occurrence of cases in the same family is often explained by improper food, bad cooking, and irregular hours, to the evil influences of which all the members are similarly subjected.
All conditions of the organism which result in a depraved or altered blood-supply, as anæmia, primary and secondary rachitis, chronic syphilis, and continued febrile diseases, are causes of intestinal indigestion. The connection of the indigestion of fats with the strumous diathesis and with phthisis is undisputed. J. Hughes Bennett traced the origin of phthisis to defective fat-digestion; strumous indigestion and the indigestion of fat are synonymous terms.
Debilitating influences, such as bad air, want of cleanliness and outdoor exercise, impair functional activity in the intestines as elsewhere. Sexual excesses, but especially masturbation, have a special influence for evil in this direction.
The influence of the mind upon the digestion of starch and fats is even greater than upon gastric digestion, for no other reason perhaps than that the former is a more complex function and less easily relieved than the latter. Prolonged or excessive mental labor does not do so much harm as mental worry, over-anxiety, and the strain and overwork of business. Professional men—lawyers, physicians, and clergymen—who become over-burdened with responsibilities, and who sympathize too much with the distresses of others, are very prone to suffer. The careworn face with lines about the mouth and forehead is one of the plainest signs of duodenal defect. The proper secretion of the juices of the intestine and normal peristalsis are impossible where brain and nerves get no rest. The too rapid mental development of the children of the present day is a fruitful source of weakened fat-and-starch digestion and of impaired development. So long as children are sent to the public school at four and six years of age, there will continue to grow up a precocious race with active brains in feeble bodies.7 This injurious result is largely brought about by the direct interference of premature brain-development with the complex intestinal processes of digestion and absorption.
7 In eight of the States and Territories the minimum age for entering the public school is fixed at four years; in seventeen States at five years; in the others, except two, at six years. The two notable exceptions are Alabama and New Mexico, where children do not enter school until the age of seven.
Wealth, with ease and inactivity, and sedentary occupations, contribute to the same end by lessening the need of food, and thus debilitating the organs of digestion by inaction. Sedentary pursuits, especially those in which the body is bent forward and constricted or compressed at the waist, interfere with active function in the intestine. This is the case in tailors, shoemakers, etc. Tight-lacing in women and a too tight trouser-band in men are injurious.
Hot climates, especially when combined with dampness, lead to disorder in the intestine and liver. This effect is most marked among persons coming from colder climates, as among the English in India, who keep up the habits of eating to which they have been accustomed at home. The lessened demand destroys the appetite, and stimulants and condiments are resorted to to whip up the inactive functions. The intestine is loaded with a mass of crude, unaltered matter which can with difficulty be disposed of. Chronic indigestion results, varied with acute attacks of diarrhoea or dysentery. The portal system is filled with an excess of albuminoid material which the liver is unable to store away. The excess is got rid of by conversion into uric acid. Lithæmia and chronic congestion and enlargement of the overloaded liver result, with their many attendant evils.