This account of Professor Pawlow’s experiment leads directly to the all important subject of the influence of mental states upon digestion and assimilation. Dr. Saleeby has published a book called “Worry, the Disease of the Age”—the very title of which shows the attitude of physicians upon this question; and the bad opinion which mankind has always entertained of such states of mind as “the blues” has now been scientifically justified. The effects of pain and pleasure upon digestion have been demonstrated by actual experiments in the laboratory of the St. Petersburg professor.

A vivid account of these experiments has been given to the writers by Dr. J. H. Kellogg, who witnessed them about a year ago. Dr. Kellogg writes:

“Professor Pawlow took Professor Benedict and myself into a quiet corner of his laboratory, and there we found a dog that had his salivary glands or ducts arranged so that by means of little tubes passing through the skin all the saliva, instead of passing down his throat, passed out through the tubes and could be collected in small glass bottles suspended beside his neck.

“The dog had been prepared beforehand by the attendant. Little empty bottles were attached to the collecting tubes, and as soon as the dog saw Pawlow, he seemed to be very happy, and wagged his tail, and his eyes gave evidence of satisfaction; but there was no flow of saliva until Professor Pawlow brought near to his nose a bottle containing some powdered meat. He took out the cork in the presence of the dog, turned out a little of it in his hand, shook it in the bottle and brought it near to the dog’s nose. The dog began to sniff it, licked his chops, snapped his jaws, reached out after it, and in less than two minutes the saliva began to flow very profusely, and it was not more than fifteen or twenty seconds before the saliva was pouring down into the bottles.

“Professor Pawlow, then, after holding the bottle out before the dog for about thirty seconds, put the stopper into it, and put it behind him out of sight, and in a very few seconds the saliva ceased to flow. Then he brought it back again, showed it to the dog, brought it near his nose, allowed him to smell it but kept it just out of his reach all the time, and the saliva poured out again freely. He continued this until the dog finally made up his mind he was not going to get any meat, and when the powder was brought near to him he paid no attention to it, but turned his head around and looked very disappointed and very ugly, and at that point, the saliva ceased to flow.

“That was a very remarkable thing to me. The meat was right there, he could smell it, but he knew he was not going to get it, so he was angry, and as his state of mind changed, the secretion of saliva was wholly arrested. I was very much surprised. Of course, I believe thoroughly in the importance of being in a happy state of mind when eating, but I really did not appreciate thoroughly the importance of those things; I did not fully appreciate how positive an inhibitor of the activity of the salivary glands an unhappy state might be.

“But a common experiment made in India shows the same idea. When an Anglo-Indian has lost anything of value, he has his whole family of servants brought to him to find out which one has stolen it. A common test is to stand them all up in a row, and then to give each one a morsel of dry rice to chew. They must chew this rice for five minutes, and then the master goes around and examines each man’s mouth. The mouth which is dry is the mouth of the culprit, and the state of that man’s mind has the effect of arresting the flow of saliva. Pawlow has shown that this is a positive physiologic law and operates upon the dogs as well as upon human beings.

“Another experiment astonished me even more than this. We followed Pawlow down through a long narrow hall and upstairs into a room which was small and secluded, in a very quiet part of the laboratory, remote from any noisy occupation, and there we found a brown dog standing on a high table. It was a delicate and very intelligent looking animal. The attendant sat near by, and the dog was prepared as the other had been. As we came in, the Professor beckoned to us to sit down on a little bench beside the wall and indicated that we should be quiet. He stepped up to the dog, looked at him, and the dog recognized him with a smile in the dog’s way of smiling!—and presently the saliva began to flow.

“Professor Pawlow was very much surprised. We had come into the room and he had offered the dog nothing, but the saliva was flowing. That was contrary to his expectation. He looked with considerable astonishment at the attendant. The attendant quietly said, ‘You have been feeding meat to the other dog, and he smells the meat on your hands.’

“The dog had such a keen sense of smell that the odor of meat on Pawlow’s hands even at a distance of several feet was sufficient to cause the saliva to flow. So he went out, washed his hands and came back. At this time, not a drop of saliva was flowing. The arrangement was such that every particle secreted must come outside of the mouth into these bottles. While we were waiting in silence, watching the dog quietly, suddenly the attendant pressed his foot without making any motion of the body at all, upon a little lever beneath his toe and the result was the causing of a high musical note to be sounded, a very high pitched tone.

“Instantly, in less than three seconds, the saliva was flowing into the tube. We waited a little while until the saliva ceased to flow, then the note was sounded again. Instantly the saliva began to flow.

“Professor Pawlow has been experimenting upon this line for a long time. Other experiments were made. One interesting experiment was with a large number of dogs. He had upon one counter a long row of dogs, about a dozen, which had their stomachs fixed in such a way, and their throats fixed also in such a way, that upon the secretion of the gastric juice in the stomach the juice would flow out into a flask.

“The dogs were suspended in a sort of harness. They had had their throats fixed so that food instead of going into the stomach came out at the throat. So as the dog ate the food, the food fell back into the plate and the dog continued eating the same breakfast over and over. These dogs had been eating the same breakfast for four hours, from six to ten o’clock in the morning, and they were still eating, and just as hungry as ever because there was no food entering their stomachs at all and their appetites were growing keener every moment, and they were having a wonderfully good time. I thought that some people I have met might enjoy such an arrangement. This really has the same effect without having your throat cut.

“I noticed that if these dogs got disgruntled, or tired, or dissatisfied, then the gastric juice would cease to flow. Sometimes the food, having been chewed a very long time, lost its flavor, and the dogs secreted no more juice; then the attendant would come along and put a little fresh food into the plate and the dogs would seize this with great avidity, and the gastric juice would begin to flow again in a perfect stream.

“These experiments have demonstrated in the most positive manner the definite connection there is between psychic conditions and the process of digestion, and have shown us that the food must be palatable, that it must address the olfactory sense agreeably, and that the mind must be in a happy state in order that the digestive process may proceed.”

And then Dr. Kellogg goes on to tell of the work of Professor Cannon, of Harvard University, who actually has made visible the digestive processes in the stomach by means of the X-ray. By feeding cats food colored with certain substances which are impervious to the X-rays, he was enabled to photograph all the actual movements of the organs concerned in the acts of digestion. It was demonstrated that certain emotions, such as anger and fear, positively stopped the whole process of digestion.

Depressing thought will affect injuriously the circulation of the blood; it will also affect the breathing. The mere attitude of the body assumed by the despondent person has its bad influence. The head droops in a melancholy fashion—and this very attitude prevents normal action of the lungs and the blood veins. Depressing thoughts destroy the appetite; and when the body does not receive its proper nourishment, the blood becomes impoverished.

“Any severe anger or grief is almost certain to be succeeded by fever in certain parts of Africa,” says Sir Samuel Baker, in the British and Foreign Medico Chirurgical Review. “In many cases, I have seen reasons for believing that cancer had its origin in prolonged anxiety,” says Sir George Paget, in his “Lectures.” “The vast majority of the cases of cancer, especially of breast or uterine cancer, are probably due to mental anxiety,” says Dr. Snow, in the London Lancet. “Diabetes from a sudden mental shock is a true, pure type of physical malady of mental origin,” says Sir B. W. Richardson in “Discourses.” “I have been surprised how often patients with primary cancer of the liver lay the cause of this ill health to protracted grief or anxiety. The cases have been far too numerous to be accounted for as mere coincidences,” says Murchison.

“Eruptions on the skin will follow excessive mental strain. In all these and in cancer, epilepsy and mania from mental causes there is a predisposition. It is remarkable how little the question of physical disease from mental influence has been studied,” says Sir B. W. Richardson.

“My experiments show that irascible, malevolent and depressing emotions generate in the system injurious compounds, some of which are extremely poisonous; also that agreeable, happy emotions generate chemical compounds of nutritious value, which stimulate the cells to manufacture energy,” says Elmer Gates, the celebrated American scientist. Gates’ experiments show with minute exactitude just how it is that one’s impalpable thoughts and emotions affect the battle of the blood, and his work makes it easier for one to understand and appreciate the portion of truth underlying such manifestations as the New Thought and Christian Science movement. There can be no doubt that men and women have practically remolded their bodies and changed the whole course of their lives by using the impalpable yet potent force of their wills. Sometimes these have been men and women seemingly without a vestige of will; and yet, by comprehending the necessity for will, they took the first steps towards attaining possession of it. Many very remarkable stories could be told illustrating this point. Professor William James, of Harvard, introduced one of the writers to a man who had been afflicted with what had seemed a helpless case of mental trouble, accompanied by physical ailments which were rapidly breaking him down; and this man had affected a complete cure through his own unaided efforts. He resolved that he could be cured, and cured he was.

We remember another instance; this time of a consumptive; a man who was so far gone that all the physicians gave up his case as hopeless. To all intents and purposes he was already a dead man, when there came to him the light of a new hope. He had spent a great deal of money in taking various “treatments” for tuberculosis, without deriving permanent benefit, and then had come to believe utterly that in only one way was there hope for the consumptive, namely, by living entirely in the open air. When seemingly at his last gasp he arrived at a branch of the Battle Creek Sanitarium at Boulder Creek, Colorado. In certain photographs of this establishment you may see on a bare hillside that stands back of the building, a narrow foot-path. This path has many turnings and windings in its lower course, but towards the top of the hill it aspires upward in a straight line. That trail was made by the consumptive who had determined that he would live, crawling on his hands and knees up the side of the hill. He positively refused to go under a roof for any consideration whatsoever. His meals were brought to him where he lay on the road side. At first he was so weak that he could only go a few feet in the course of a day, and had to drag himself along in a wavering line. But he began to improve—he went on improving—until, finally, along the track on which he had crawled he was running at top speed.

And a little while ago this man was one of the athletes who took part in Professor Irving Fisher’s endurance competition between flesh-eating athletes and vegetarians; and he proved to be best of them all! He doubled the best record made by any Yale man in the deep-knee bending contest. The most enduring Yale man was able to make the deep-knee bend—which is a very severe test of physical endurance—twelve hundred times. The consumptive who had cured himself went twenty-four hundred times. He thinks nothing of a ten or fifteen mile ran before breakfast in the morning.

It is important to apply these truths to the question of nutrition. It is positively harmful to eat food when one is gloomy or low spirited or worried or angry.

You may object to this that you cannot at will make an optimist of yourself at meal times, and turn on a flow of good humor as you draw water from a tap. But you can at least refrain from eating, and if you do you will discover that the real hunger which is bound to develop is a very strong emotion. It will drive away any ordinary attack of the blues very quickly; and will call up pleasant anticipations of the joy of food to assist the digestive processes.