THE VALUE OF PAIN. PAIN is one of the essential conditions of progress. Not merely in the sense of being part of the friction which necessarily accompanies all movement, but as a vital precedent of all possibility of movement. Ask any biologist what is the first and most important property of living matter and he will tell you that it is "irritability," the power of responding to stimuli or impressions. Touch with a needle point the most beautiful and brilliant crystal and you get absolutely no response, turn to the grayest and flabbiest bit of ditch-water animal-jelly that you can find and he moves himself away from the steel at once. And if he feels at all he must He can feel, therefore he lives. be able to feel pain as well as pleasure. portant that he should perceive the disagreeable stimulus than the agreeable, for the former needs to be moved away from while the latter does not. Leave him capable of only pleasurable sensations and he will be destroyed inside of an hour. In this earliest form the powers of sensation and of responding to impressions are combined in the same cell, but as the organism becomes more complex, more extensive and powerful movements are called for, and special cells are set aside for contractile purposes alone, leaving to the surface cells the duty of sensation only. Later it becomes not merely a question of escape but also of retaliation, and a central office to combine the muscle-strands in orderly military movements is needed and the ganglion-brain is called into being. In the meantime the surface cells have been dividing up the work of feeling among themselves, some have educated themselves to catch the finest variations in the light-rays some confine their entire study to the sound-waves, others to the changes of temperature, while the vast majority of them simply refine upon their original powers of contact-perception or touch. Thus out of the simple possibility of discomfort arise the five senses, their muscle-standing-army and their joint judicio-executive brain. Pain is the mother of the mind, and muscle is its father. Nor can this powerful factor in the creation of the body-organism be permitted to "rest upon the seventh day," like the Jahveh of Genesis, when its work is apparently completed. The possibility of the continuance of life absolutely depends upon its incessant activity. Cut the nerve which connects any part or organ with the conscious brain and you place it in serious peril at once. Precisely as if you blindfolded a man and then turned him loose in an enemy's country, or as if you cut the wire which connected an outlying military post with headquarters. You may cut the motor nerve which conveys orders from the brain, or, what is equivalent, destroy the "motor centre" of the part in the brain with comparative impunity, as far as the nutrition of the limb is concerned; it loses the power of motion, but even the muscles retain their bulk for a long time in spite of lack of exercise and the general health if the member remains perfect. But it is far otherwise when sensation is destroyed. The benumbed hand or foot goes stumbling along like a blind man, cutting itself here, burning itself there, rasping its surface against a hundred objects, and from every merest scratch an ulcer forms. So long as all its cells are in health and vigor and can live on the standard rations of the rest of the body, issued to them through the blood-vessels, all goes well, but the moment any of them fall below par from injury or otherwise and cannot notify the central commissariat of the fact, they fall into the plight of a baby trying to live on government rations of hard-tack and salt-beef. heat and swelling about a wound which we term "inflammation" is merely a forced and special feeding-up of the neighboring cells to enable them to breed rapidly and fill the gap, and while in excess it is a source of danger in itself, in its absence there can be no healing. That Observe it is not the loss of the power to pass the signal "All's well" that is injurious, it is the inability to report discomfort. Not the absence of all sensation, but the absence of painful ones that is fatal. For instance, in paralysis of the aged, one of the chief dangers to life is from the formation of ulcers about the back and hips due solely to pressure against the mattress and hence known as "bedsores." The peculiar danger of these is first that, sensation being abolished, they will form without the patient's knowledge, and in neglected cases will often attain the size of the palm of the hand and a depth of an inch or more before they are discovered, and second, that communication with the brain being cut off, little or no inflammation occurs and they are extremely difficult to heal. It is no uncommon thing to see them six inches in diameter and an inch deep and yet with scarcely enough inflammatory reaction around them to redden the skin at their edges. This absence of pain and consequent inflammation not only impairs healing-power but also deprives the general system of one of its chief barriers against the absorption of the products of decay, and a fatal bloodpoisoning is extremely apt to occur. A peculiar illustration of the uses of pain is afforded by that dread disease leprosy. Here one of the earliest symptoms is the loss of sensation in a hand and arm or foot while the muscular power is unaffected. Many a victim has first discovered his condition by severely burning or cutting himself without feeling pain. In one dramatically tragic case, a planter who supposed himself in perfect health thoughtlessly caught a heated lamp-chimney which was falling, and didn't know it was burning him until the smell of his scorching fingers attracted his attention! What is the result? In a very short time tiny cracks, bruises, and scratches develop all over the hand or limb affected, these rapidly grow into ulcers and either heal very slowly or steadily deepen until fingers, toes, nay even hands and feet are completely amputated by them, or the limb is so drawn and crippled by the great scars that it becomes almost useless. There are of course active processes of destruction at work as well in the disease, but the greater part of the terrible deformities of the limbs produced by leprosy are due solely to this negative destruction of sensation and its consequences. In modern hospitals it is found that by keeping lepers in bed, in comfortable wards and protecting their extremities against injury and irritation in every possible way, their lives may be very greatly, if not almost indefinitely, prolonged. But there is also another way in which pain is of marked benefit in case of disease or injury, and that is by securing rest for the part affected. The agony of an inflamed joint, for instance, is an imperative order to the muscles controlling its movements to keep it perfectly still and motionless. And the order is usually strictly obeyed. So important does nature consider it that, by a curious transference, the pain of a diseased hip-joint, for instance, will be felt by the sufferer in the knee and ankle, so as to keep the whole limb at rest. This function of pain is beautifully illustrated in the lower animals. A broken leg in a dog or a deer, for instance, will be so carefully protected against the pain of movement, supported against the other limb, rested against the side of the body and swung along with such a gentle movement, with its toe just trailing on the ground, that the results are often equal to the best that we can boast with all our splints and bandages. Truly, pain is nature's splint. A similar protective influence is exerted over the inflamed lung by the acute distress of pleurisy. "But," says some one, "what of those diseases in which pain is the principal evil, in which no structural changes can be found in any way proportionate to the agony endured, what of neuralgia, of blinding 'sick-headache,' of sciatica? Is not the pain the disease in these cases?" By no means. It cannot be too emphatically asserted that pain always means something. It does not occur simply as an accident of chance, still less for the purpose of developing patience, or as a "means of grace," but as a pointed reminder that something is going wrong. Neuralgia is the cry of the nerves for more sunlight, "sick-headache" a protest against eye-strain. In themselves comparatively harmless, as danger-signals they are simply invaluable. Hence the seeming paradox, that those who suffer most, often live the longest: the sensitiveness of their nerves absolutely compels them to halt at the very threshold of danger. Pain is literally the price of life. And this brings us to the question: "What is pain?" abstractly considered. "What is the difference and what the relation between it and pleasure?" We are all perfectly clear in our own minds on these questions, in the concrete, from personal experience, but how shall we define our conception? On careful ultimate analysis we are driven to the somewhat unexpected conclusion that pain and pleasure are really both vibrations of one and the same chord. That the very sensitiveness which makes the one possible, necessarily makes the other also possible. That the only way to prevent painful impressions, from our environment, is to destroy the mechanism which permits the reception of pleasurable ones. In short, life without pain would necessarily be life without pleasure. The old mythic poets made a shrewd guess at this scientific truth when they described the life on Olympus as "colorless," "joyless," and sang of the "twilight of the gods." And Kipling's prophetic insight has caught the same ray, in his magnificent parable, the greatest poetic conception of the century, "The Children of the Zodiac." More than this, the two sensations are not merely vibrations of the same chord, but varying degrees of the same vibrations. The difference between them is one not of kind but of degree. Almost any pleasurable sensation can be transformed into a painful one by simply increasing its intensity, and many painful ones into pleasur able merely by decreasing their intensity or changing the circum stances. The instantaneous coolness of a piece of ice placed upon a parched tongue is delicious, but let contact be prolonged only a few seconds and the very same "coolness" becomes intense discomfort. The similar "transformation" of the warmth of a Yule log is another illustration which of course suggests itself. A flood of golden sunlight is the most pleasing sight which falls upon our retina, but throw the rays directly into the eye and a dazzling pain takes the place of the former enjoyment. A gentle friction of the body-surface is an agreeable sensation to nearly every one, but in |