'These changes in the body,' he wrote in the review paper he sent to the American Journal of Physiology late in 1913, 'are, each one of them, directly serviceable in making the organism more efficient in the struggle which fear or rage or pain may involve; for fear and rage are organic preparations for action, and pain is the most powerful known stimulus to supreme exertion. The organism which with the aid of increased adrenal secretion can best muster its energies, can best call forth sugar to supply the labouring muscles, can best lessen fatigue, and can best send blood to the parts essential in the run or the fight for life, is most likely to survive. Such, according to the view here propounded, is the function of the adrenal medulla at times of great emergency.'

A surgeon should give as little pain as possible while he is treating the patient, and no pain at all when he charges his fee.

All pain is one malady with many names.

Doctors have been exposed—you always will be exposed—to the attacks of those persons who consider their own undisciplined emotions more important than the world's most bitter agonies—the people who would limit and cripple and hamper research because they fear research may be accompanied by a little pain and suffering.

Hence when a person is in great pain, the cause of which he cannot remove, he sets his teeth firmly together, or bites some substance between them with great vehemence, as another mode of violent exertion to produce a temporary relief. Thus we have the proverb where no help can be has in pain, 'to grin and abide;' and the tortures of hell are said to be attended with 'gnashing of teeth.'Describing a suggestion of the origin of the grin in the present form of a proverb, 'to grin and bear it.'

It is the doctors who desert the dying and there is so much to be learned about pain.

Men ought to know that from the brain, and from the brain only, arise our pleasures, joys, laughter and jests, as well as our sorrows, pains, griefs and tears. Through it, in particular, we think, see, hear, and distinguish the ugly from the beautiful, the bad from the good, the pleasant from the unpleasant, in some cases using custom as a test, in others perceiving them from their utility. It is the same thing which makes us mad or delirious, inspires us with dread or fear, whether by night or by day, brings sleeplessness, inopportune mistakes, aimless anxieties, absent-mindedness, and acts that are contrary to habit. These things that we suffer all come from the brain, when it is not healthy, but becomes abnormally hot, cold, moist, or dry, or suffers any other unnatural affection to which it was not accustomed. Madness comes from its moistness.

On the one hand, then, in the reproductive functions proper—menstruation, defloration, pregnancy and parturition—woman is biologically doomed to suffer. Nature seems to have no hesitation in administering to her strong doses of pain, and she can do nothing but submit passively to the regimen prescribed. On the other hand, as regards sexual attraction, which is necessary for the act of impregnation, and as regards the erotic pleasures experienced during the act itself, the woman may be on an equal footing with the man.

One cannot help a man to come to accept his impending death if he remains in severe pain, one cannot give spiritual counsel to a woman who is vomiting, or help a wife and children say their goodbyes to a father who is so drugged that he cannot respond.

Pain is a sensation produced by something contrary to the course of nature and this sensation is set up by one of two circumstances: either a very sudden change of the temperament (or the bad effect of a contrary temperament) or a solution of continuity.

Physiological response to thinking and to pain is the same; and man is not given to hurting himself.

Science is a wonderful thing, but it has not yet succeeded in maximizing pleasure and minimizing pain, and that's all we asked of it.

The body of man has in itself blood, phlegm, yellow bile and black bile; these make up the nature of this body, and through these he feels pain or enjoys health. Now he enjoys the most perfect health when these elements are duly proportioned to one another in respect of compounding, power and bulk, and when they are perfectly mingled.

The brain of man, like that of all animals is double, being parted down its centre by a thin membrane. For this reason pain is not always felt in the same part of the head, but sometimes on one side, sometimes on the other, and occasionally all over.

The further away the chronic abdominal pain in a child is from the umbilicus the more likely an organic cause.

The greatest evil is physical pain.

The most essential nature of a sentient being, which is to move to pleasure and from pain.

The physical signs of measles are nearly the same as those of smallpox, but nausea and inflammation is more severe, though the pains in the back are less.

There are some arts which to those that possess them are painful, but to those that use them are helpful, a common good to laymen, but to those that practise them grievous. Of such arts there is one which the Greeks call medicine. For the medical man sees terrible sights, touches unpleasant things, and the misfortunes of others bring a harvest of sorrows that are peculiarly his; but the sick by means of the art rid themselves of the worst of evils, disease, suffering, pain and death.

Throw out opium, which the Creator himself seems to prescribe, for we often see the scarlet poppy growing in the cornfields, as if it were foreseen that wherever there is hunger to be fed there must also be a pain to be soothed; throw out a few specifics which our art did not discover, and it is hardly needed to apply; throw out wine, which is a food, and the vapors which produce the miracle of anaesthesia, and I firmly believe that if the whole materia medica, as now used, could be sunk to the bottom of the sea, it would be all the better for mankind,—and all the worse for the fishes.

Thus it might be said, that the vegetable is only the sketch, nor rather the ground-work of the animal; that for the formation of the latter, it has only been requisite to clothe the former with an apparatus of external organs, by which it might be connected with external objects.
From hence it follows, that the functions of the animal are of two very different classes. By the one (which is composed of an habitual succession of assimilation and excretion) it lives within itself, transforms into its proper substance the particles of other bodies, and afterwards rejects them when they are become heterogeneous to its nature. By the other, it lives externally, is the inhabitant of the world, and not as the vegetable of a spot only; it feels, it perceives, it reflects on its sensations, it moves according to their influence, and frequently is enabled to communicate by its voice its desires, and its fears, its pleasures, and its pains.
The aggregate of the functions of the first order, I shall name the organic life, because all organized beings, whether animal or vegetable, enjoy it more or less, because organic texture is the sole condition necessary to its existence. The sum of the functions of the second class, because it is exclusively the property of the animal, I shall denominate the animal life.