Early American Manual Therapy

Studies in the Osteopathic Sciences
The Physiology of Consciousness: Volume 3
Louisa Burns, M.S., D.O., D.Sc.O.
    Those centers of earliest phylogenetic development lying around the base of the hemispheres are concerned in the reactions which answer most speedily and forcibly the environmental changes to which the race has been accustomed. While the cerebral hemispheres were developed to a certain extent among animals lower than mammals, and while they are a conspicuous factor of mammalian brains, yet their functional development seems to be a matter of comparatively recent times. Even among mammals of considerable development the cerebral cortex seems to be largely non-functional. The centers around the base of the hemispheres, the nulei of the thalamus and corpus striatum, the other interbrain centers and the midbrain centers, seem to perform the functions of properly relating the reactions to the variations of the surrounding conditions. Even among man these centers appear to control those reactions of immediate reply to certain environmental conditions.

    During the phylogenetic development of these centers they became functional in giving reply to many and varied changes, and these duties they still perform, in man, without the intermediation of consciousness. Through the activity of these centers reactions are controlled which have every appearance of purposeful foresight, and which yet are not associated with consciousness in any degree. This function of the lower centers is of great biological significance, since the activities of these centers secure for the cortical neurons the time and energy needful for the performance of those duties concerned in the conscious phenomena. The lower centers control those reactions called instinctive, or emotional, or affectional, which depend upon racial history for the effectiveness of the answer which they make to environmental changes.


    The structural relationships of these ganglionic centers may be given in brief. The corpus striatum, the optic thalamus, the hypothalamic nucleus, the red nucleus and substantia nigra are those most easily recognized. Probably the claustrum should be included. The interpeduncular ganglion, the central gray matter around the aqueduct of the cerebrum (Sylvius), the nucleus pontis, and perhaps others of the groups of cells in the interbrain, midbrain, pons and medulla may be concerned in modifying the nature of the instinctive and emotional reactions. The cerebellar cortex and ganglia seem to be concerned in coordinating the descending impulses, but not in determining the nature of the reactions.

The Corpus Striatum
    The corpus striatum is a part of the cerebral hemisphere. It is developed from the floor of the cerebral vesicle partly by a thickening of this floor with an associated specialization of neuron groups, and partly by the ingrowing of certain fiber groups from its own centers and from other parts of the nervous system. Phylogenetically, it is of great age. Its first relationships were with the olfactory impulses, as is the case also of the cortex itself.

    The corpus striatum is of rather complex structure. It includes centers which are probably of different functions, as they certainly are of different relationships. The body is divided into two parts by the internal capsule; the inner of these is called the caudate nucleus, the outer is called the lenticular nucleus. The lenticular nucleus is divided by bands of fibers into three parts, at least. The outer of these is the putamen; the inner masses are grouped as the globus pallidus.

The Putamen

    The putamen is the outer zone of the lenticular nucleus. It is separated from the claustrum by the thin external capsule. The insula occupies a position just external to the claustrum, and is of about the same extent as the putamen. The putamen is pigmented, and is rather freely supplied with blood. This gives it a reddish color, quite different from the color of the underlying globus pallidus. The putamen sends a large bundle of fibers to the thalamus, probably chiefly to the median nucleus. The putamen exchanges fibers with the caudate nucleus, the globus pallidus and the cortex, chiefly of the insula and the fronto-parietal region. The relations of the putamen to the claustrum are not well studied.

The Globus Pallidus

    The globus pallidus is light in color, partly because its cells contain no pigment and partly because its blood supply is rather scanty. Like the putamen, it exchanges fibers with the caudate nucleus, the thalamic centers, probably the median nucleus chiefly, and with the putamen and the cortex. The globus pallidus receives collaterals and axons from the motor area of the cortex, and it sends a bundle of fibers, the olivary bundle, to the inferior olive and to the nucleus pontis.

The Caudate Nucleus
    The caudate nucleus occupies a position beneath and lateral to the lateral ventricle. The posterior extension, or tail of the caudate nucleus is continuous with the amygdala. Probably the olfactory impulses are partly coordinated in this ganglion. The caudate nucleus exchanges fibers with the lenticular nuclei, the anterior tubercle of the thalamus, and probably it receives collaterals and axons from the cortex.

    The striato-thalamic fibers include fibers from both lenticular and caudate nuclei to several of the thalamic, hypothalamic and other interbrain and midbrain centers, both of the same and of the opposite sides.

The Optic Thalamus
    The optic thalamus is developed from the second cerebral vesicle, and is a part of the interbrain. It includes many centers of varying functions and relationships. Probably the fact of the various connections and functions of the thalamus is the reason why such various and often contradictory accounts are given in both experimental and clinical data concerning this body. It is evident that with many centers of varying functions the clinical evidence and the experiments which do not recognize the subdivisions could hardly be expected to harmonize. The description given by Nissl includes twenty different thalamic nuclei. These may be grouped, for convenience sake, into the median, lateral, ventral and posterior nuclei, the nucleus of the anterior tubercle, the pulvinar, the nucleus habenulae, and the internal and external geniculate bodies. The relationships of these may be briefly given. In the first place, each of these centers probably exchanges axons or collaterals from each of the others, both of the same and of the opposite sides. With the exception of the nucleus of the anterior tubercle, the gray matter of each nucleus is more or less continuous with neighboring nuclei. Thus the difficulty of describing the nuclei as separate centers is apparent. The nuclei seem to be all associated with the corpora striata of both sides. This relationship is more intimate in some cases than in others. The nuclei of the thalamus seem to exchange fibers with almost or quite all of the primary sensory areas, and probably of all areas of the cortex.

    The individual connections of the thalamic nuclei have been described in part as follows:

    The lateral nucleus receives the fibes of the lateral fillet, the spino-thalamic tract, and the fibers from some of the lower centers concerned in the common sensory conduction path. It transmits the impulses concerned in the sensations called common sensory to the cortex of the parietal lobe, chiefly the postcentral gyrus and the neighboring cortical areas. Descending fibers from the same areas are carried to the lateral nucleus.

    The ventral nucleus sends fibers to the insula and the operculum, and to the region which bounds the Sylvian or lateral fissure. It also receives fibers from these areas.

    The median nucleus receives fibers from the insula, the second and third frontal gyri, and the neighboring areas. It sends fibers to these areas also. It seems to be chiefly a descending path for the impulses concerned in written or spoken speech. Injuries of the thalamus are sometimes associated with peculiarities of speech, not resembling aphasia. The median nucleus sends fibers to the same areas.

    The posterior nucleus lies between the internal and the external geniculate bodies. It is associated with the cortical area between the visual and the auditory overflow areas. Fibers pass both to and from the cortex.

    The external geniculate body receives the fibers of the optic tract, together with the pulvinar, and transmits the impulses carried by these fibers to the primary visual area in the occipital lobe. Descending fibers from the large pyramidal and stellate cells of the primary visual area enter the external geniculate body.

    The pulvinar receives also the optic tract fibers, and transmits visual impulses to the visual cortex. The gray matter of the pulvinar and the external geniculate body is continuous.

    The internal geniculate body receives the fibers of the lateral fillet, and transmits the auditory impulses carried thereby to the primary auditory area of the first and perhaps the second temporal gyri. Descending fibers from the same and probably neighboring areas are carried to the internal geniculate body, and to the posterior quadrigeminates.

    The anterior tubercle of the thalamus is concerned in the reflex actions, and probably also the instinctive and emotional reactions, following olfactory impulses. By means of the fornix, the corpora mammillaria and the fasciculus mammillaria the olfactory cortex is related to the nucleus of the anterior tubercle and to the gray matter around the aqueduct. This center sends impulses to the viscero-motor centers of the medulla, pons and midbrain, and probably indirectly to the viscero-motor centers of the cord.

    The ganglion habenulae receives the fibers of the medullary striae, which transmit the olfactory impulses to the habenulae. This center sends impulses by way of the fasciculus retroflexus to the interpeduncular ganglion, which in turn transmits impulses to the nuclei of the motor cranial and spinal nerves.

    Other masses of gray matter in and upon the surface of the thalamus have been described, but not fully enough for any conclusions to be drawn concerning their functions or relationships.

Other Centers
    The substantia nigra, hypothalamic nuclei and the red nucleus may be described together in this connection. All receive collaterals or axons from the cortex, especially the prefrontal, frontal and temporal lobes. All receive fibers from the thalamus, striatum, and other ganglionar centers of the cerebrum; each exchanges fibers with the others, and each sends fibers to the nucleus pontis and perhaps also to the cerebellum directly.

    The red nucleus receives fibers from the nucleus dentatus of the cerebellum, and sends fibers to the lateral nucleus of the thalamus. It is thus part of the indirect sensory conduction path. The red nucleus thus appears to be an important station both in the motor and the sensory paths. It is also, probably because of this double relationship, an important center for the coordination of the instinctive and emotional reactions.

    The interpeduncular ganglion receives fibers from the red nucleus, substantia nigra, hypothalamic nuclei and the cortex, either directly or indirectly. The fibers from this ganglion pass to the motor nuclei of the cranial and spinal nerves. The ganglion is thus mainly a part of the descending pathway.

    The gray matter around the aqueduct includes nerve cells whose axons descend near the rubro-spinal tract to enter the viscero-motor centers, chiefly of the medulla and pons, but also, probably, of the cord and the midbrain.

    Other centers of the basal region have been described by different authors. The nuclei and centers of the pons, medulla, cerebellum and cord are concerned in the transmission and coordination of the motor impulses resulting from the activity of the cortical and the ganglionar centers of the cerebrum.

Experimental Stimulation
    Experimental stimulation of the ganglionar centers causes various reactions. It is not possible to locate exactly the centers stimulated by the electrodes in animals so small as cats, dogs, guinea pigs and white rats. (These are the only animals subjected to these tests in the Pacific College Laboratory of Physiology.) The animals were anesthetized before the skull was opened. Stimulation of the region of the red nucleus gave rise to movements resembling those of the normal animal when angered The arching back and tail, the spitting of the cat or growling of the dog, the clawing and fighting movements, illustrated very well the expressions of anger. The stimulation of the median nucleus of the thalamus and of the subthalamic region gave practically the same results. When the animal had been kept under the anesthetic for too long a time, or after the stimulation had been too long continued, or when the animal subject to the test was sick or starved, the reactions were sometimes rather, characteristic of fear than of anger. (Stray and half-starved animals and those which are sick are often sent to us for speedy and easy death.)
Stimulation of the same centers increases the heart beat and apparently the blood pressure. The gall bladder may be emptied into the intestine. The peristaltic movements of the stomach and intestines are usually increased by the same stimulation. No other manifestations of emotional states than fear and anger were observed.
Function of the Ganglionar Centers
    These facts are in harmony with the effects of certain emotional states upon physiological conditions. According to Mayer, Pawlow and others, it is the emotional or affective states of pleasure, desire, etc., which cause the increased glandular activities in the so-called “psychic” secretions. Cannon and De la Paz, at Harvard, have shown that in the cat fright increases the secretion of the adrenals. The presence of bile in the circulating blood after right or anger is well known. The increased secretion of tears in grief, laughter and other emotional states is due to the activities of the ganglionar centers.
    Lesions of these centers cause various symptoms. Lesions of the striate bodies are associated usually with paralysis, due to the involvement of the internal capsule. Lesions involving the nuclei of the striate bodies alone either have not been described, or no symptoms referable to the injured part were noted before death. Lesions of the thalamus give various symptoms. Authors do not agree very well. Dejerine gives the thalamic syndrome as including paresthesias, lack of coordination of delicate movements, probably including speech, and an emotional instability or a loss of the emotional reactions.
Thalamic Lesions
    Dana recognizes three groups of symptoms from thalamic lesion: First, disturbance of the intelligence due to the general effects of brain injury; second, symptoms due to pressure upon adjoining parts, or their involvement in the lesion; third, those due to the thalamic injury itself. The general symptoms vary according to the individual, and have little bearing upon the question of localization. The pressure symptoms include hemiplegia, due to the injury of the internal capsule. Dana’s cases include papillary disturbances and paralysis of reflexes, but not the disturbances of the eye movements, the forced movements of the body, the choreic and athetoid movements described by other observers. Dana finds the most definite symptoms connected with injury to the thalamus to be central pain, some anesthesia, and perhaps hemianopsia. The two latter may be due to extrathalamic lesion. Dana considers that some of his cases indicate an effect produce upon the visceral centers and the temperature of the body.

    The pain involves the paralyzed side only; it involves the arms and hands most, the leg and foot next, and rarely the head. The peripheral parts cause most distress—that is, the hands and feet are more painful than arms and legs. The pain is not like ordinary pain, but is a sort of burring discomfort, more distressing than sharp or aching pain. Even when the pain itself seems only slight it causes great annoyance.

    In none of his cases was there any paralysis of the emotional expressions, or any decided explosions of laughter or crying, unless there were symptoms involving other parts of the brain. Dana agrees with Roussy, who believes that the thalamus itself does not control the emotional reactions. He agrees also with Meynert, who considers the thalamus the organ which receives sensations and registers them in consciousness. The lesions as described involve the lateral nucleus, but not the subthalamic region.

    The extreme complexity of the relationships existing between the various ganglionar centers of the cerebrum probably accounts for the lack of symptoms referable to the lack of activity of these centers; that is, the lack of function of one might be scarcely noticed if the other centers were able to perform their duties in a normal manner. The lack of emotional reactions does not arouse attention in as great degree as the excess of such reactions, especially when the person attending the patient has not been associated with him during his normal periods. Post mortem records of lesions of these centers, with accounts of the symptoms preceding death, rarely give any exact account of the location of the lesion. It is greatly needed that more exact descriptions of the location of lesions should be given.

    The reactions characteristic of the emotional states and the reactions called instinctive are, at least in part, governed by the ganglionar centers. The consciousness of the emotional or affective states is due to several factors: First, the conditions responsible for the emotional state are usually a matter of consciousness; second, the visceral and somatic reactions as they are being performed are made conscious.

Phylogeny of the Ganglionar Functions

    The development of the emotional reactions is lost in the beginnings of life itself. The securing of foods and the resistance of the attacks of enemies make up the sum total of the activities of the lower animals. The taking up of food materials from the surrounding fluids is a process which greatly resembles the union of atoms, at least in a superficial manner. It may be that the assimilation of food is, indeed, a matter of the affinity of the molecules of the biogen for certain atoms or radicals capable of being used as sources of energy, but this is a matter of theory only.

    Certainly the reactions concerned in the life processes of cells seem to indicate that the use of the food materials of the surroundings is largely a matter of chemical attraction. The use of foods probably represents the beginning of the complex metabolism reactions which underlie the more complex activities necessary to the seeking of foods by the higher organisms. In seeking foods, a process made necessary by the development of organisms of complex structure, the function of the nervous system comes prominently into play. The actions concerned in this process necessitate the resistance to attack.

    Positive chemotaxis may represent the beginning of food seeking; the attraction of the foodstuffs may represent the beginnings of sex attraction, such as is displayed in the union of parameciums, and the beginnings of the sum of what are included in the terms friendship, love, patriotism, and all the feelings we have for beautiful, and admirable, and desirable things. Negative chemotaxis, then, must represent the beginnings of the repulsion which the simple organisms exert toward those things in their neighborhood which are harmful or merely useless. This repulsion affects those organisms also which are harmful, or which may be merely useless. The chemical configurations of the living molecules or biogens probably are of a certain structure, and the structures of different biogens should account for the different reactions of the different organisms. From this negative chemotaxis of the unicellular organism to the sum of the negative chemotaxis of the cells of the multicellular organism there is never any exact line to be drawn. It would certainly be an unwarranted conclusion that atoms “hate” one another, or that conjugating parameciums “love” one another, as it is an unwarranted conclusion that the sum of the positive chemotaxis of the cells of our own bodies represents all that there is in ourselves of loving or admiring, or our feelings of patriotism, and loyalty, and friendship. Between these limits of negative and positive chemotaxis, phototaxis, and the tropisms and other physical forces, to the complex emotional reactions of man, lie infinite gradations, but never any unpassable gulf.

    During the series of changes, which can not yet be truly termed developmental processes, the reactions become more complex as the structure becomes more complex, and as increasing size and organic demands necessitate more and more variated supplies. The demands necessitated by the development of sexual reproduction modifies the nature of the reactions in the processes of constant variation and constantly acting evolutionary processes.

    The activities necessitated by hunger include the chase of food and the fight of offense. The protection of the individual against the attacks of other individuals also hungry, necessitates flight and the fight of defense. Among animals of higher types the fight is associated with the display of certain phenomena: the showing of the teeth, which has for its worth the increased ferocity of appearance as well as the increased speed of their use; the tension of the muscles, which has for its value the increased speed and energy of their contractions; the increased blood pressure, which increases both the efficiency of the muscles and of the nervous system; the protrusion of the claws, which thus are ready for attack or defense, and the inhibition of the nerve centers concerned in other reactions. The animal stimulated to the fighting reactions shows no indications of hunger, thirst, or any other physical need; he seems to suffer no pain or sense of heat or cold, nor does he seem able to see or to hear anything except the object of his attack or his defense.

    Human beings suffer the same quality of inhibition under emotional stress. The angry man feels no hunger, thirst, pity, loyalty, and scarcely any sense of pain. He lacks humor or affection, and often the sense of truth is lost. The angry man is apt to say things untrue, and unjust, and disloyal, though he may be true, and honest, and faithful at all times except during anger. The cortical neurons exercise the same inhibitory effects upon the action of the emotional centers which they do upon the spinal centers. The control of the emotional centers may be secured by the lowering of the liminal value of system of neurons which relate the cortical and basal center in function.

    The feeling called anger is the consciousness aroused by the occurrence of the somatic and visceral changes produced by the action of the ganglionar centers controlling the reaction, and of the circumstances calling these activities into play. A fairly good imitation of the feeling of anger may be produced by imitating the appearance of anger, while the best appearance of anger is produced by imagining the circumstances productive of anger to be true, while the somatic reactions are imitated as nearly as possible.

Relations of Anger and Fear
    When the circumstances of life are such as to render an efficient reply difficult or impossible, then the activities characteristic either of fear or of anger result. If the individual is competent to meet the emergency, the reaction resembles anger; if the individual is not competent to meet the emergency, then the reaction resembles fear.

    Among human kind the same thing is true. If any person meets environmental conditions which are abhorrent to him at a time when he is tired, or overfatigued, or suffering from some exhausting and non-stimulating disease, then the tendency is for him to “give up,” to display fear and a lack of urgent endeavor to correct the conditions as he finds them. He is more apt to overvalue the strength of the opposing forces than those of his own side. He is incapable of meeting the emergency, and knows it; therefore he fears. He may be merely absurdly conservative, which is a human development of fear.

    But the same abhorrent conditions may meet him at another time, when he is strong and well, and with normal blood pressure and clean blood; then he reacts to the conditions with the manifestations of that power and earnestness and certainty of success which is the higher development among mankind of anger.

    The lack of food is associated with increasing restlessness or increasing irritability. The long-continued lack of food is associated with the loss of the energy required for movements, and starvation results. At first lack of food increases the irritability of the unicellular organism and of the individual cells of the multicellular organism. The presence of hunger is associated with the motor restlessness which aids in the finding of foods, in the unicellular organism. Among animals whose nervous systems are efficient, the neuron threshold is lowered by the lack of food. The motor restlessness thus initiated is helpful in the finding of food. The same thing is true among the human race. The lack of food in the fluids of the body lowers the liminal value of the neurons, so that less stimulation is required to initiate the nerve impulse. Since the neurons of the greatest specialization are first affected by the condition, it is evident that there is a certain amount of common sense in the idea that it is necessary to starve a talent in order to make a genius. Unfortunately, if talent is starved too long, a dead talent rather than a live genius results.
The very fact of the seeking of foods by any number of animals brings about two conditions: one is, that animals seeking food may themselves be sought as food; the other is, that of two animals finding the same food, only one can eat. Warfare thus results. The struggle for existence necessitates the survival of the fittest to eat. The fact that any individual uses the food in the producing of the greatest amount of energy therefrom is, in the earliest developmental stages, reason for the survival of that animal. The struggles for food or for mates, with the visceral and somatic variations, make up the reaction called anger in animals. In man the term anger is used in two senses. Anger as a form of activity includes the series of reactions, both somatic and visceral, which are associated with an attack upon some force which is, or may be, injurious or an impediment to the activities of the person attacked, or for whose sake the attack is being made. This series of phenomena may be observed in a slight degree among animals of very inferior development, even those without the nervous system. The simultaneous attack upon foodstuffs by two unicellular organisms may resemble anger, though the resemblance must be only superficial. The problem of the feelings associated with the manifestations of anger and other passions is that of consciousness in general.
Physiology of Anger
    The phenomena associated with the reaction called anger have undoubted biological value. The hairs and other forms of exoskeleton are raised by the activities of the pilo-motor nerves. This makes the animal more ferocious in appearance, and also it protects him from the claws of his enemy. The contraction of the pilo-motors among man causes the phenomenon of “goose flesh.” As a means of protection or of causing a more ferocious appearance, this reaction is of very little biological value among mankind. The lips are raised and the teeth protruded. This is the beginning of the attack, and it also causes the more ferocious appearance. The pupils are dilated; the eyes thus seem larger, and sight may be made more acute. The blood pressure becomes higher through the increase in the heart’s action, and the energy of the contracting muscles is greater because of the increased blood supply. The peristalsis of stomach and intestines are lessened, the kidneys secrete less freely, the glands of the body secrete less freely, except the sweat and salivary glands, whose secretion is, among certain animals, a mode of defense. The “frothing at the mouth” of the insanely angry has this significance, as has also the free perspiration associated with certain conditions of anger. Among men, also, a difference of the circulation is noted during anger.

    While the blood pressure is higher by the increased heart’s action, the splanchnic vessels are contracted. By this means the blood pressure is increased also, and the blood is diverted to the skeletal muscles, where it is needed during the fight. If the stimulation continues and the storm increases, the activities of the vaso-constrictor center are increased, and the peripheral vessels also are contracted. In the first instance the fact and hands of the angry person are red, but during the more ferocious stimulation the face and hands become white. So the white anger represents usually the more intense reaction. This varies to a certain extent among individuals.

Consciousness of Anger
    The term anger is also applied to the feeling. Anger in this sense is the consciousness of the visceral and somatic activities, plus the consciousness of the conditions which initiated the reactions. Anger does not result from the recognition of the conditions, no matter how abhorrent, which do not have any personal effect. The interference with the liberties of a neighbor affect us, because he is our neighbor; but people do not become angry in any marked degree on account of the injury or the slavery of people with whom one has no relationship. It is true that relationship may be of many degrees, and that by the multiplication of methods of intercourse the term neighbor is beginning to include many who would have been strangers in the older times.

    With the development of the intermediate areas the phenomena included in the term anger becomes more or less dissociated and the elements recombined, both in reactions and in consciousness. As a result, instead of the simple manifestations of attacking and of repelling attacks, of employing the fight as an agent for the securing of foods or of mates, among men the same forces are employed in slightly different manners, with great increase in the efficiency of human effort.

    The recognition of an impediment to the motor activities of certain animals leads to a manifestation of anger, and to the movements of destruction and attack. Among men, the recognition of an impediment to activities leads, or should lead, to a study of the nature of the impediment, with a view to its efficient and speedy removal. Among savages, as among animals, the immediate and angry attack is the result of unwelcome deeds or words of other persons or animals, and the fight thus initiated is apt to be very destructive and ferocious. Among civilized people the occurrence of unwelcome deeds or words on the part of acquaintances should lead to the inhibition of any reaction, until the action of the intermediate areas, the recollection of past deeds and words, and perhaps further sensory impulses of sight and sound, may affect the nature of the ultimate reaction. It may be that this postponement of the reaction will increase the vigor and destructiveness of that expression of anger, but more often the proper appreciation of the surroundings inhibits altogether the angry reaction, and much destruction is prevented.

Value of Anger
    The proper appreciation of the surroundings which lead to the beginning of anger may result in determining a new mode of activity. The existence of an impediment to the activities of a normal person may lead him to endeavor to remove the obstacle. If a river impedes his progress, he may bridge the river. If a strip of land prevents the sailing of his vessels from one ocean to another, he may dig a canal across the isthmus. If things are too far away for him to see them clearly, he may make himself magnifying lenses and other instruments. If he is very much in earnest about finishing any piece of work, the increased blood pressure, the contracted muscles of mastication, the shortened breath, the tension of the lips, all show the resemblance to the primeval anger which met an obstacle. The manifestation of urgent endeavor is associated with the phenomena of anger, whose elements are isolated and recombined in a manner which makes for increased efficiency and wisdom of reaction.

    Thus anger and the reactions associated with the adverse environment may be made a source of power. What is ordinarily called force of character depends largely upon the manner in which the occurrence of adverse environmental conditions affects the individual. Efficiency, self-control, the control of others, the power of attainment in any line, ambition in its best as well as in its unadmirable sense, all these depend upon the dissociation and recombination of the forces concerned in the series of activities called anger.

    Fear as a series of reactions to impending attack includes both somatic and visceral changes. The feeling of fear is the consciousness of these somatic and visceral changes, plus the consciousness of the circumstances to which the reactions are due. The last factor in the feeling of fear may be absent, as in the fear present when awakening from nightmare. The somatic changes are such as adapt the body to concealment or to flight. The motor centers are wholly or in part inhibited. The body thus becomes relaxed. Among certain animals this relaxation is so complete as to cause feigned death. The animals thus affected by fear are saved from the attacks of other animals who refuse to eat food found dead. The complete relaxation causes complete quiet, so that such animals may be unseen by their enemies. The inhibition of the motor centers may be partial, as in the case of the “lame” quail, with which many children are familiar.

    The visceral manifestations of fear are such as lessen the injury about to be inflicted. The sweat glands usually increase in activity. This lessens the efficiency of the claws of the attacking animal. The pilo-motors are increased in activity, and the hairs, feathers, and other forms of exoskeleton become erect. Thus the claws, etc., of the enemy are less efficient than otherwise. The peripheral blood vessels are contracted, and thus the danger of bleeding is lessened. The heart is increased in activity and the blood pressure is raised, partly as the result of the peripheral constriction and partly as the result of the increased heart action. The efficiency of the muscles of defense is thus increased, and the danger of the attack is lessened. Also, if flight be possible, this increased blood pressure increases the efficiency of the muscles concerned in that performance. It has lately been shown by Cannon and De la Paz, at Harvard, that fright increases the secretion of adrenalin. This probably is one factor in the rise of the blood pressure under fear. The peristalsis of the stomach and intestines is first decreased, then increased under fear, as under anger. The same thing is true of the bile ducts. Among human beings the visceral effects of fear and anger are somewhat modified by the activities of the cortical centers. This control produces irregular and often disadvantageous reactions, and the visceral effects of the emotional reactions may be decidedly serious under certain conditions. Rarely there results more than temporary disorders, unless the person so affected suffered some abnormal conditions before the occurrence of the emotional state.

Stage Fright
    The reactions characteristic of fear are, like all other emotional and instinctive reactions, unmodified by the surrounding circumstances not associated with the disturbance. Thus, the phenomena of stage fright include the increased perspiration, the contraction of the pilo-motors, the partial inhibition of the motor centers, and the contraction of the peripheral vessels, which should be efficient in protesting from impending attack, even though the cause of the stage fright lies in the very fact that only friends of undoubted worth are present; in other words, the urgency of the desire to make the most perfect reply to the demands of any occasion increases the danger of stage fright and renders the apt reaction the more improbable. By the activities of the cortical centers the danger of the stage fright may be recognized; the person may prepare himself so fully for the impending demands that no incongruity between his preparation and the requirements of the occasion exist. Stage fright is then almost impossible.
Value of Fear
    Fear is concerned in like manner with the forces which inhibit too urgent and immediate reaction. Too great stimulation of certain centers causes inhibition of other centers. The use of fear in its biological sense by the human race is one of the forces of the race. Not cowardly is the fear which preserves life and makes advancement possible. Not cowardly is wise conservatism. Cowardly is the fear which constantly inhibits all reaction; cowardly is the fear which refuses to accept the unity of the race, which saves one’s self alone. The fear which preserves all, which leads to that inhibition which permits the association of the impulses concerned in memories and judgments, that is the fear which enters into every good judgment, which modifies every step toward advancement until it can be determined whether advancement and not retrogression is the direction in which the proposed step is taken. The development of the intermediate areas, with their unlimited powers of recombinations of the elements of experience, would lead to unlimited absurdities without the inhibitory effects of fear in its biological sense. What death is to sexual reproduction in evolution, that is what fear is to the activities of the intermediate areas in consciousness. Sexual reproduction necessitates the variations of hereditary qualities, the development of the intermediate areas necessitates the variation of experiences; death in the one case and fear in the other prevent too great variations from the accepted order, and wholly support the laws which make for steadfast, and certain, and unlimited advancement.
    The feeling called horror resembles that of fear in part. The difference is due to the fact that in horror the impending danger is perceived as tending toward some other person or thing. Thus, in horror the consciousness is modified by the fact that the posterior intermediate areas are active, rather than the anterior intermediate areas. Thus, the differences between horror and fear are not apparent among animals whose cortical centers are not functional. Among people whose posterior association areas are not well developed, as in the excessively egoistic or self-centered person, the emotional states of horror and fear are almost or quite identical.
    Disgust is a feeling produced by the consciousness of increased salivary flow, reversed peristalsis, and the contraction of the pilo-motors, with more or less of increased sweat. In its most pronounced type disgust is associated with vomiting, and the preliminary symptoms of vomiting are the source of the consciousness of disgust. The feeling may be aroused by the presence of conditions not directly related to the digestive tract, as in the consideration of repulsive acts, unethical or immoral actions, etc. The word disgusting is used improperly as applied to conditions of loss, failure, and the like, unless some factor associated with physical repulsion be present. Disgust as applied to the acts of others is not present when these acts are considered in an impersonal manner. The most abhorrent crimes arouse no feelings of any kind in the person who studies those crimes in the effort to determine their causes scientifically and with the view of adding to the knowledge which is to prevent crime in the future.
Sex Instincts
    The psychology of sex has been studied thoroughly by Havelock Ellis. Any attempt at a resume of his five volumes would be beyond allowable limits. For a discussion of the psychical phenomena associated with sexual manifestations recourse must be had to his studies. For the present purpose it is necessary only to suggest the basic nature of the phenomena which lie at the very beginning of all advancement of the race. For by asexual reproduction no opportunity, or at least very little opportunity, is found for variation. With sexual reproduction begins the possibility of endless variations of the hereditary traits, and, as a result of this variation, the possibilities of survivals and death by means of which the development of the races become assured. Sexual reproduction means sexual selection, and, through this selection in its widest meaning, the selection of those qualities which make for advancement. The sexual psychology, then, must underlie much of what we are ordinarily pleased to think of as pertaining to things higher than the physical. As the sensory impulses reaching the primary sensory areas may be combined and interpreted through the activity of the overflow areas, and the significances and memories thus brought into being again combined through the activity of the intermediate areas into abstractions and ideals and prophecies for future grandeur, so the basic principles of the elements of sexual selection may be dissociated from one another and from physical reproduction, and the elements of choice, and pleasure, and admiration may be recombined and again dissociated.

    The decisions made in this way may be variously affected by the associational processes, until a series of ideals and concepts arises from which all that is fine in art, and music, and architecture, and education have been developed. All that is admirable in social life, and much of the enthusiasm and joy of living, have thus been made a part of consciousness, and form a large, and important, and admirable part of daily life.

Limitations of Instincts

    The laws acting through the ages, which make for the persistence of constantly higher types, of constantly more complex structure, constantly able to make greater and more economic use of natural forces, are efficient in storing within the nervous systems of the higher animals those reactions which are for the good of the race in the ordinary environment of the race. No account is taken, in the development of the instinctive and emotional reactions, of the possibility of the exceptional cases, either of the individual or of his environment. Thus instinctive reactions are perfectly adapted to ordinary cases; indeed, the instinctive reactions appear to surpass in wisdom and perfection the most thoroughly studied voluntary actions. But the instinctive reactions fail in the exceptional cases.

    The limits of the value of the emotional and instinctive reactions lies in this, that these reactions are apt to fail in wisdom in the exceptional cases. It is true that often they do not fail in the exceptional cases, and that persons often do “instinctively” the things which are decidedly wise and fortunate in the exceptional cases. But such conditions are themselves exceptional. Under the exceptional cases the activities of the cortical neurons are preeminently the efficient sources of the associational and volitional impulses upon which wise reactions must depend.