Part 10

If in a long emotional strain the brain is beaten down; if the number of "low-efficiency" cells increases, the driving power of the brain is correspondingly lessened and therefore the various organs of the body may escape through the very inefficiency of the brain to produce in them forced activity. On the other hand, if the brain remains vigorous, the kidneys may take the strain and break down; if the kidneys do not break, the blood-vessels may harden; if the blood-vessels are not affected, the thyroid may become hyperplastic and produce Graves' disease; if the thyroid escapes, diabetes may develop; while if the iron constitution of the mechanism can successfully bear the strain in all its parts, then the individual will break his competitors, and their mechanisms will suffer in the struggle.

This whole train of deleterious results of body activation without action may be best observed and studied in that most emotional of diseases--exophthalmic goiter. In this disease the constantly stimulated distance ceptors dispossess the contact ceptors from the common path, and drive the motor mechanism to its own destruction, and the patient has the appearance of a person in great terror, or of a runner approaching the end of a Marathon race (Figs. 16 and 48 to 54).

Exophthalmic goiter may result from long emotional or mental stress in those cases in which the thyroid takes the brunt of the strain upon the mechanism. As adrenalin increases blood-pressure, so thyroid secretion increases brain activity, and increased brain activity in turn causes an increased activation of the motor mechanism as a whole.

We know that a deficiency or lack of thyroid secretion will inhibit sexual emotion and conception, will produce stupidity and inertia; will diminish vitality. On the other hand, excessive thyroid secretion drives the entire mechanism at top speed; the emotions are intensified; the skin becomes soft and moist, the eyes are brilliant and staring; the limbs tremble; the heart pounds loudly and its pulsations often are visible; the respiration is rapid; the stimulation of the fear mechanism causes the eyes to protrude (Fig. 16); the temperature mounts at every slight provoca-tion and may reach the incredible height of 110'0 even. In time, the entire organism is destroyed-- literally consumed--by the concentration of dynamic energy. It is interesting to note that in these patients emotion gains complete possession of the final common path; they are wild and delirious-- but they never have pain.

All the diseases caused by excessive motor activity may be called kinetic diseases. Against the conditions in life which produce them man reacts in various ways. He intro-

{illust. caption = FIG. 51.--CROSS-COUNTRY RACE. Winner of six-mile cross-country race showing typical expression of exhaustion. (Copyright by Underwood and Underwood, N. Y.) duces restful variety into his life by hunting and fishing; by playing golf and tennis; by horseback riding; by cultivating hobbies which effectually. turn the current of his thoughts{illust. caption = FIG. 52.--{A B and C} from the consuming stress and strain of his business or professional life. These diversions are all rational attempts to relieve tension by self-preservative reactions. For the same reason man attempts to relieve the strain of contention with his fellow-man by unions, trusts, corporations. In spite of all efforts, however, many constitutions are still broken daily in the fierce conflicts of competition. We know how often the overdriven individual endeavors to minimize the activities of his motor mechanism by the use of agents which diminish brain activity, such as alcohol, tobacco, and various narcotics. Occasionally also, some person, who can find no respite from his own relentless energies, seeks relief in oblivion by suicide.

Most fortunately, two fundamental instincts--self-preservation and the propagation of the species--act powerfully to prevent this last fatal result, and instead the harassed individual seeks from others the aid which is lacking within himself. He may turn to the priest who seeks and often secures the final common path for faith in an over-ruling Providence, a faith which in many incontrovertible instances has proved sufficient in very truth to move mountains of lesser stimuli; or he turns to a physician, who too often treats the final outcome of the hyperactivity only. The physician who accepts the theory of the kinetic diseases, however, will not only repair as far as he may the lesions caused by the disordered and forced activities, but will, by compelling and forceful suggestion, secure the final common path for right conduct, that is, for a self- and species-preservative course of action as opposed to wrong conduct-a self- and species-destructive course of action.

By forcefully imparting to his patient the knowledge of the far-reaching effects of protracted emotional strain, of overwork, and of worry, the physician will automatically raise his threshold to the damaging activating stimuli which have produced the evil results. Even though some parts of his organism may have been permanently disabled, a patient thus protected may yet rise to a plane of poise and efficiency far above that of his uncontrolled fellows.

In extreme cases it does not seem unreasonable to believe that the uncontrolled patient might be rescued by the same principle which has proved effective in saving patients from the emotional and traumatic strain of surgical operations--the principle of anoci-association. That is, by disconnecting one or more of the activating organs from the brain, the motor mechanism might be saved from its self-destruction.

Under this hypothesis, that man in disease, as in health, is the product of his phylogeny as well as of ontogeny, the sphere of the physician's activities takes on new aspects of far-reaching and inspiring significance. Prognosis will become definite in proportion to the physician's knowledge not only of the ontogenetic history of the individual patient, but also of the phylogenetic history of the race. As that knowledge increases, as he appreciates more and more keenly the significance of environment in its effect upon individual development, in so far will the physician be in a position to contribute mightily to the welfare of the race.

THE KINETIC SYSTEM[*]

In this paper I formulate a theory which I hope will harmonize a large number of clinical and experimental data, supply an interpretation of certain diseases, and show by what means many diverse causes produce the same end effects.

Even should the theory prove ultimately to be true, it will in the mean time doubtless be subjected to many alterations. The specialized laboratory worker will, at first, fail to see the broader clinical view, and the trained clinician may hesitate to accept the laboratory findings. Our viewpoint has been gained from a consideration of both lines of evidence on rather a large scale.

The responsibility for the kinetic theory is assumed by myself, while the responsibility for the experimental data is shared fully by my associates, Dr. J. B. Austin, Dr. F. W. Hitchings, Dr. H. G. Sloan, and Dr. M. L. Menten.

From H. K. Cushing Laboratory of Experimental Medicine, Western Reserve University, Cleveland.

Introduction

The self-preservation of man and kindred animals is effected through mechanisms which transform latent energy into kinetic energy to accomplish adaptive ends. Man appropriates from environment the energy he requires in the form of crude food which is refined by the digestive system; oxygen is taken to the blood and carbon dioxid is taken from the blood by the respiratory system; to and from the myriads of working cells of the body, food and oxygen and waste are carried by the circulatory system; the body is cleared of waste by the urinary system; procreation is accomplished through the genital system; but none of these systems was evolved primarily for the purpose of transforming potential energy into kinetic energy for specific ends. Each system transforms such amounts of potential into kinetic energy as are required to perform its specific work; but no one of them transforms latent into kinetic energy for the purposes of escaping, fighting, pursuing, nor for combating infection. The stomach, the kidneys, the lungs, the heart strike no physical blow-their role is to do certain work to the end that the blow may be struck by another system evolved for that purpose. I propose to offer evidence that there is in the body a system evolved primarily for the transformation of latent energy into motion and into heat. This system I propose to designate "The Kinetic System."

The kinetic system does not directly circulate the blood, nor does it exchange oxygen and carbon dioxid; nor does it perform the functions of digestion, urinary elimination, and procreation; but though the kinetic system does not directly perform these functions, it does play indirectly an important role in each, just as the kinetic system itself is aided indirectly by the other systems.

The principal organs which comprise the kinetic system are the brain, the thyroid, the adrenals, the liver, and the muscles. The brain is the great central battery which drives the body; the thyroid governs the conditions favoring tissue oxidation; the adrenals govern immediate oxidation processes; the liver fabricates and stores glycogen; and the muscles are the great converters of latent energy into heat and motion.

Adrenalin alone, thyroid extract alone, brain activity alone, and muscular activity alone are capable of causing the body temperature to rise above the normal. The functional activity of no other gland of the body alone, and the secretion of no other gland alone, can cause a comparable rise in body temperature--that is, neither increased functional activity nor any active principle derived from the kidney, the liver, the stomach, the pancreas, the hypophysis, the parathyroids, the spleen, the intestines, the thymus, the lymphatic glands, or the bones can, per se, cause a rise in the general body temperature comparable to the rise that may be caused by the activity of the brain or the muscles, or by the injection of adrenalin or thyroid extract. Then, too, when the brain, the thyroid, the adrenals, the liver, or the muscles are eliminated, the power of the body to convert latent into kinetic energy is impaired or lost. I shall offer evidence tending to show that an excess of either internal or external environmental stimuli may modify one or more organs of the kinetic system, and that this modification may cause certain diseases. For example, alterations in the efficiency of the cerebral link may yield neurasthenia, mania, dementia; of the thyroid link, Graves' disease, myxedema; of the adrenal link, Addison's disease, cardiovascular disease.

This introduction may serve to give the line of our argument. We shall now consider briefly certain salient facts which relate to the conversion of latent into kinetic energy as an adaptive reaction. The experimental data are so many that they will later be published in a monograph.

The amount of latent energy which may be converted into kinetic energy for adaptive ends varies in different species, in individuals of the same species, in the same individual in different seasons; in the life cycle of growth, reproduction and decay; in the waking and sleeping hours; in disease and in activity. We shall here consider briefly the reasons for some of those variations and the mechanisms which make them possible.

Biologic Consideration of the Adaptive Variation in Amounts of Energy Stored in Various Animals

Energy is appropriated from the physical forces of nature that constitute the environment. This energy is stored in the body in quantities in excess of the needs of the moment. In some animals this excess storage is greater than in other animals. Those animals whose self-preservation is dependent on purely mechanical or chemical means of defense--such animals as crustaceans, porcupines, skunks or cobras--have a relatively small amount of convertible (adaptive) energy stored in their bodies. On the contrary, the more an animal is dependent on its muscular activity for self-preservation, the more surplus available (adaptive) energy there is stored in its body. It may be true that all animals have approximately an equal amount per kilo of chemical energy-- but certainly they have not an equal amount stored in a form which is available for immediate conversion for adaptive ends. Adaptive Variation in the Rate of Energy Discharge

What chance for survival would a skunk have without odor; a cobra without venom; a turtle without carapace; or a porcupine shorn of its barbs, in an environment of powerful and hostile carnivora? And yet in such an hostile environment many unprotected animals survive by their muscular power of flight alone. It is evident that the provision for the storage of "adaptive" energy is not the only evolved characteristic which relates to the energy of the body. The more the self-preservation of the animal depends on motor activity, the greater is the range of variation in the rate of discharge of energy. The rate of energy discharge is especially high in animals evolved along the line of hunter and hunted, such as the carnivora and the herbivora of the great plains.

Influences That Cause Variation in the Rate of Output of Energy in the Individual

Not only is there a variation in the rate of output of energy among various species of animals, but one finds also variations in the rate of output of energy among individuals of the same species. If our thesis that men and animals are mechanisms responding to environmental stimuli be correct, and further, if the speed of energy output be due to changes in the activating organs as a result of adaptive stimulation, then we should expect to find physical changes in the activating glands during the cycles of increased activation. What are the facts? We know that most animals have breeding seasons evolved as adaptations to the food supply and weather. Hence there is in most animals a mating season in advance of the season of maximum food supply so that the young may appear at the period when food is most abundant. In the springtime most birds and mammals mate, and in the springtime at least one of the great activating glands is enlarged--the thyroid in man and in animals shows seasonal enlargement. The effect of the increased activity is seen in the song, the courting, the fighting, in the quickened pulse, and in a slightly raised temperature. Even more activation than that connected with the season is seen in the physical state of mating, when the thyroid is known to enlarge materially, though this increased activity, as we shall show later, is probably no greater than the increased activity of other activating glands. In the mating season the kinetic activity is speeded up; in short, there exists a state--a fleeting state--of mild Graves' disease. In the early stages of Graves' disease, before the destructive phenomena are felt, the kinetic speed is high, and life is on a sensuous edge. Not only is there a seasonal rhythm to the rate of flow of energy, but there is a diurnal variation--the ebb is at night, and the full tide in the daytime. This observation is verified by the experiments which show that certain organs in the kinetic chain are histologically exhausted, the depleted cells being for the most part restored by sleep.

We have seen that there are variations in speed in different species, and that in the same species speed varies with the season of the year and with the time of day. In addition there are variations also in the rate of discharge of energy in the various cycles of the life of the individual. The young are evolved at high speed for growth, so that as soon as possible they may attain to their own power of self-defense; they must adapt themselves to innumerable bacteria, to food, and to all the elements in their external environment. Against their gross enemies the young are measurably protected by their parents; but the parents--except to a limited extent in the case of man--are unable to assist in the protection of the young against infectious disease.