But this is not all. We know that engineers never build engines without having first de cided what power they wish them to develop, at what speed they are to drive a boat or a train, what load they must be able to draw or to lift. It is but common sense to suppose that the human digestive apparatus is con structed, so to speak, for a certain power, that there is a certain quantity of material which suits it best, and that if it has to digest a quantity greatly in excess of that it will be overstrained or overloaded, and again indi gestion may result. But it is equally common sense to suppose that, like machines invented by man, the digestive apparatus of a human being is adapted not only for a certain quantity of work, but also for a certain kind of work. The digestive apparatus of a worm is suited for the earthy food from which it draws its nourishment; and the apparatus of an ox is different, because its feeding is different. So there are certain kinds of food appropriate for man which his stomach and bowels, in their healthy condition, find natural to them, and certain other substances which they tend to reject as offensive to them.
Now, knowing these things, and many other circumstances have a similar bearing on the subject—knowing these things, is it not per fectly absurd to imagine that there can be one cure for indigestion, that the bare fact of a person suffering from indigestion is sufficient to indicate what treatment should be adopted? And is it not apparent that there may be as many ways of treatment as there are causes of the complaint, and that the only rational course to take is to ask what is the exact nature of the indigestion—does it arise from improper food, or from too much or too little food? is it due to too hurried eating? is the seat of indigestion in the stomach or in the bowels? and so on— and to let the treatment be guided by the re sults of such patient and careful inquiry ? In short, is it not plain that the cure for the in digestion that afflicts a person whose bad teeth, or whose want of teeth, prevent him properly chewing his food is quite different from the treatment that will cure the indigestion of an other whose teeth are perfect, and who chews his food well, but whose liver is sluggish, and so hinders the digestive process. Probably a
slight stimulant to the slow liver, such as podo phyllin, will help the latter individual, but is worse than useless to the former, whose in digestion will probably be driven away by a properly constructed set of artificial teeth.
The truth that these considerations ought to enforce is the necessity of determining, as accu rately as possible, the stage of the digestive process that is interfered with, and the cause of the interference whose result is indigestion, before steps are taken to rectify what is wrong; and this truth, the need of discovering the cause, is as applicable to every other disease, and for similar reasons.
What the causes of indigestion are may now be briefly set down.