THE DIGESTIVE SYSTEM.
Diseases of the digestive system are very numerous and important. In some respects, indeed, they are the most important class of diseases that fall to be considered in a work of this kind. In a sense the digestive organs are more open to the attack of disease than any others. In normal circumstances a person's lungs, for example, are well guarded; his heart is beyond his control, and cannot be directly affected by him ; but his stomach is daily at his mercy, is daily the victim of his whim, his taste, or his passion, has no fixed periods of work and repose, like lungs and heart, but is at one time overburdened, and at another per haps in a state of inactivity for many hours.
Everyone knows the effects of overwork on the body, or of overwork on a rarticular part of the body—an arm, for instance. We all know what is the feeling of a tired arm, or a wearied set of muscles, and we all interpret the feeling properly enough, and have usually sufficient sense to give the jaded arm or muscles rest in order to recovery. But we do not speak of a wearied stomach ; and multitudes of people do not understand what that sensation is, not be cause they never experience it, but because they never rightly interpret it. Yet a stomach tired with overwork, and giving rise to feelings which are its load calls for rest, is probably as common a sensation as a fatigued muscle. Its calls, however, are not properly understood, and instead of repose it more often receives excitement. A tired stomach is as unfit for the full discharge of its proper work as a wearied arm is unfit for its labour. Its per
formance will be incomplete. The very first girt of the process of preparing nourishment or all the organs of the body is improperly arried out, and the effects of that first failure t is difficult fully to appreciate. If every xgan and tissue of the body seek their nourish uent from the blood, and if the quality and inantity of the blood are mainly dependent ipon material obtained from the food, which ias undergone a process of preparation in the tomach and intestine, it is evident how the fitness of the blood to nourish the body neces itates the integrity of the digestive process. Again, the digestive system is one of the nai» gateways of disease. We all know how ipeedily poisons may destroy life. But most spisons are harmless when applied to the out ide of the body. It is only after they gain titrance to the body, chiefly after they gain kccess to the current of blood and are able to Mack directly one organ or another, that their ?fleets can be obtained. Their chief way of 4aining entrance is by the stomach, though it s not their only way, as we shall see when we ;onie to consider poisons. Now this is true tot only of those things that everyone regards N poisons. The old proverb, "One man's meat s another man's poison," is a very true one, and points to the fact that what one man may at and drink with satisfaction and benefit mother man may not eat or drink without serious disturbance.