the origin and nature of emotions-第6章
按键盘上方向键 ← 或 → 可快速上下翻页,按键盘上的 Enter 键可回到本书目录页,按键盘上方向键 ↑ 可回到本页顶部!
————未阅读完?加入书签已便下次继续阅读!
mation; _e。 g_。; in the training of athletes; the rhythmic discharge of muscular energy at such intervals that the resting stage is not reached before a new exercise is given results in a gradual ascent in efficiency until the maximum is reached。 This is summation; and summation plays a large role in the development of both normal and pathologic phenomena。
We have now pointed out the manner in which at least a part of the nervous energy of man may be discharged。 The integrative action of the nervous system and the discharge of nervous energy by phylogenetic association may be illustrated by their analogy to the action of an electric automobile。 The electric automobile is composed of four principal parts: The motor and the wheels (the muscular system and the skeleton); the cells of the battery containing stored electricity (brain…cells; nervous energy); the controller; which is connected with the cells by wiring (the receptors and the nerve…fibers); and an accelerator for increasing the electric discharge (thyroid gland?)。 The machine is so constructed that it acts as a whole for the accomplishment of a single purpose。 When the controller is adjusted for going ahead (adequate stimulus of a receptor); then the conducting paths (the final common path) for the accomplishment of that purpose are all open to the flow of the current from the battery; and the vehicle is integrated to go ahead。 It spends its energy to that end and is closed to all other impulses。 When the controller is set for reverse; by this adequate stimulus the machine is integrated to back; and the battery is closed to all other impulses。 Whether integrated for going forward or backward; if the battery be discharged at a proper rate until exhausted; the cells; though possessing no more power (fatigue); have sustained no further impairment of their elements than that of normal wear and tear。 Furthermore; they may be restored to normal activity by recharging (rest)。 If the vehicle be placed against a stone wall; and the controller be placed at high…speed (trauma and fear); and if the accelerator be used as well (thyroid secretion?); though the machine will not move; not only will the battery soon be exhausted; but the battery elements themselves will be seriously damaged (exhaustionsurgical shock)。
We have now presented some evidence that nervous energy is discharged by the adequate stimulation of one or more of the various receptors that have been developed in the course of evolution。 In response to an adequate stimulus; the nervous system is integrated for a specific purpose by the stimulated receptor; and but one stimulus at a time has possession of the final common path the nerve mechanisms for action。 The most numerous receptors are those for harmful contact; these are the nociceptors。 The effect of the adequate stimulus of a nociceptor is like that of pressing an electric button that sets great machinery in motion。
With this conception; the human body may be likened to a musical instrumentan organthe keyboard of which is composed of the various receptors; upon which environment plays the many tunes of life; and written within ourselves in symbolic language is the history of our evolution。 The skin may be the 〃Rosetta Stone〃 which furnishes the key。
Anoci…association
By the law of phylogenetic association; we are now prepared to make a practical application of the principles of the discharge of nervous energy。 In the case of a surgical operation; if fear be excluded and if the nerve…paths between the field of operation and the brain be blocked with cocain;'*' no discharge of energy will be caused by the operation; hence no shock; no exhaustion; can result。 Under such conditions the nervous system is protected against noci…association; resulting from noci…perception or from an adequate stimulation of nociceptors。 The state of the patient in whom all noci…associations are excluded can be described only by coining a new word。 That word is 〃anoci…association〃 (Fig。 14)。
'*' See footnote; page 4。@@@
The difference between anesthesia and anoci…association is that; although _inhalation anesthesia_ confers the beneficent loss of consciousness and freedom from pain; it does not prevent the nerve impulses from reaching and influencing the brain; and therefore does not prevent surgical shock nor the train of later nervous impairments so well described by Mumford。 _Anoci…association_ excludes fear; pain; shock; and postoperative neuroses。 _Anoci…association_ is accomplished by combining the special management of patients (applied psychology); morphin; inhalation anesthesia; and local anesthesia。
We have now presented in summary much of the mass of experimental and clinical evidence we have accumulated in support of our principal theme; which is that the discharge of nervous energy is accomplished in accordance with the law of phylogenetic association。 If this point seems to have been emphasized unduly; it is because we expect to rear upon this foundation a clinical structure。 How does this hypothesis apply to surgical operations?
Prevention of Shock by the Application of the Principle of Anoci…association
Upon this hypothesis a new principle in operative surgery is founded; _i。 e_。; operation during the state of _anoci…association_。 Assuming that no unfavorable effect is produced by the anesthetic and that there is no hemorrhage; the cells of the brain cannot be exhausted in the course of a surgical operation except by fear or by trauma; or by both。 Fear may be excluded by narcotics and special management until the patient is rendered unconscious by inhalation anesthesia。 Then if; in addition to inhalation anesthesia; the nerve…paths between the brain and the field of operation are blocked with cocain;'*' the patient will be placed in the beneficent state of _anoci…association_; and at the completion of the operation will be as free from shock as at the beginning。 In so…called 〃fair risks〃 such precautions may not be necessary; but in cases handicapped by infections; by anemia; by previous shock; and by Graves' disease; etc。; anoci…association may become vitally important。
'*' See footnote; page 4。@@@
Graves' Disease
By applying the principle of the discharge of nervous energy by phylogenetic association; and by making the additional hypothesis that in the discharge of nervous energy the thyroid gland is stimulated through the nervous system; we can explain many of the phenomena of Graves' disease and may possibly discover some of the factors which explain both its genesis and its cure。
In the wild state of animal life in which only the fittest survive in the struggle for existence; every point of advantage has its value。 An animal engaged in battle or in a desperate effort to escape will be able to give a better account of itself if it have some means of accelerating the discharge of energy some influence like that of pouring oil upon the kindling fire。 There is evidence; though perhaps it is not conclusive; that such an influence is exerted by the thyroid gland。 In myxedema; a condition characterized by a lack of thyroid secretion; there is dulness of the reflexes and of the intellect; a lowered muscular power; and generally a sluggish discharge of energy。 In Graves' disease there is an excessive production of thyroid secretion。 In this disease the reflexes are increased; the discharge of energy is greatly facilitated; and metabolism is at a maximum。 The same phenomena occur also after the administration of thyroid extract in large doses to normal subjects。 In the course of sexual activities there is an increased action of the thyroid; which is indicated by an increase in its size and vascularity。 That in fear and in injury the thyroid; in cases of Graves' disease; is probably stimulated to increased activity is indicated by the increased activity of the thyroid circulation; by an increase in the size of the gland; by the histologic appearance of activity in the nuclei of the cells; and by an increase of the toxic symptoms。 Finally; Asher has stated that electric stimulation of the nerve supply of the thyroid causes an increased secretion。 The origin of many cases of Graves' disease is closely associated