Incomplete as this sketch is, it may yet suggest how readily one part of this complex machinery may be thrown out of gear, and further how not one part can suffer without all being disordered. Solid food given to the child before it has cut its teeth, enters the stomach unreduced to pulp by the grinders, and unmixed with the saliva, which should help its solution, and which the undeveloped salivary glands do not yet furnish. Too large a quantity of food, or food of an unsuitable character, on which the gastric juice cannot act readily, may pass into a state of fermentation; vomiting, flatulence, sour and offensive breath will be the result, and the food will pass into the intestine unprepared to be acted on by the bile. Exposure to cold, or the opposite condition of excessive heat, may disturb the action of the liver, and interfere with the secretion of bile; and the food will then pass along the intestine in a state unsuitable for absorption. Or, again, the mesenteric glands may be irritated by long-continued imperfect performance of the earlier stages of digestion, or their structure may be altered, and mesenteric disease, or consumption of the bowels, as it has been termed, may result. From want of muscular power, or from want of care on their part who have charge of the child, the bowels may become habitually constipated. Health will then suffer, if the child carries about with it for days together matters which can serve no useful purpose, but which are to the body what an ill-kept dustbin is to the rest of the house. Lastly, if the kidneys perform their duties imperfectly in consequence of exposure to cold, or of the changes which some diseases, such as scarlatina, sometimes bring about in their structure, the blood will be imperfectly purified; dropsy and various forms of inflammation may result; or the brain and nervous system may be disordered, and death in convulsions may attest the dangerous nature of this blood-poisoning.
It would take too long to go in detail through all the phases of disordered digestion in early life. Much has been already anticipated in a former part of this book, especially with reference to the troubles of digestion in infancy and early childhood. There is, indeed, but one form of indigestion whose characters are so special as to require that I should enter into any detail with reference to it.