Some experiments performed on dogs whose stomachs were kept open for observation will, perhaps, make the situation more clear. If a dog was allowed to eat meat in the usual way, its presence in the stomach caused the reflex centers to send orders to the gastric cells to commence secretion. The mere irritation caused by the presence of objects in the stomach was not enough, for the introduction of indigestible substances, or rubbing the lining with sand, or a glass rod, produced no gastric juice. Meat introduced directly from the outside, not through the mouth, still stimulated the juices. Thus it seemed to be purely a reflex performance—the ganglia seemed to say "you press the right button, we do the rest," the mind seemed to be unnecessary. Nevertheless, if the dog was allowed to swallow the meat, which was removed through a slit in the throat, and not permitted to enter the stomach, gastric juice was as cheerfully secreted as usual. This was puzzling enough, but worse was in store, for if the dog smelled and saw the meat, without even biting it, gastric juice was formed in larger amounts than if the meat were put into the stomach without the knowledge of the dog. Plainly, reflex action here played no part, and mental conditions of anticipation, pure emotion in fact, occupied the whole stage.
In other words, the stomach may be controlled in two ways, either mechanically by contact with food, or mentally by the production of emotions. If one fails, the other is still available. If food does not produce gastric juice, the proper mental states may be made to supply the deficiency. The problem of mental healing is here made absolutely clear; we can no longer deny that it is possible. The only difficulty is the method of production of the proper mental and emotional states. This is the most important and fascinating aspect of the subject, but space forbids its discussion in this place, as it leads into the realm of hypnotism, subliminal consciousness, suggestion and double personality. The experimenters were unfortunately unable to obtain data about the mental conditions of the dog, and thus we can not state what the results would have been upon its stomach of the memory of past feasts, the hope of future ones, or the belief or dream that there was meat in the stomach. We must wait for a satisfactory knowledge of the whole subject until some person shall appear with an opening into his stomach, like Alexis St. Martin, who, to our intense regret, died too soon to demonstrate the facts of christian science.
Not only is the stomach largely influenced by mental states, but we all know that joy, sorrow, anger and other emotions cause that extremely rapid and violent action of the heart that we call palpitation, while fright stops its action, through the pneumogastric, so that fainting occurs, or even death. Eage and other mental conditions sometimes intensify the action of the liver enough to bring about