the origin and nature of emotions-第8章
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ped the specific type of nociceptors which are adapted for their specific protective purposes； and which； when adequately stimulated； respond in a specific manner in accordance with the law of phylogenetic association； so； the abdominal viscera have developed equally specific nociceptors as a protection against specific nocuous influences。 The principal harmful influences to which the abdominal viscera have been exposed during vast periods of time are deep tearing injuries by teeth and claws in the innumerable struggles of our progenitors with each other and with their enemies （Fig。 9）； peritonitis caused by perforations of the intestinal tract from ulcers； injuries； appendicitis； gall…stones； etc。； and overdistention of the hollow viscera by various forms of obstruction。 Whatever may be the explanation； it is a fact that the type of trauma which results from fighting corresponds closely with that which causes the most shock in the experimental laboratory。 Division of the intestines with a sharp knife causes no pain； but pulling on the mesentery elicits pain。 Ligating the stump of the appendix causes sharp； cramp…like pains。 Sharp division of the gall…bladder causes no pain； but distention； which is the gall…bladder's most common pathologic state； produces pain。 Distention of the intestine causes great pain； but sharp cutting or burning causes none。 In the abdominal viscera； as in the superficial parts； nociceptors have presumably been developed by specific harmful influences and each nociceptor is open to stimulation only by a stimulus of the particular type that produced it。
As a result of the excitation of nociceptors； with which pain is associated； the routine functions； such as peristalsis； secretion； and absorption are dispossessed from the control of their respective nervous mechanisms； just as they are inhibited by fear。 This hypothesis explains the loss of weight； the lassitude； the indigestion； the constipation； and the many alterations in the functions of the various glands and organs of the digestive system in chronic appendicitis。 It readily explains also the extraordinary improvement in the digestive functions and the general health which follows the removal of an appendix which is so slightly altered physically that only the clinical results could persuade one that this slight change could be an adequate cause for such far…reaching and important symptoms。 This hypothesis explains certain gall…bladder phenomena likewise； indigestion； loss of weight； disturbed functions； etc。；and it may supply the explanation of the disturbance caused by an active anal fissure； which is a potent noci…associator； and the consequent disproportionate relief after the trivial operation for its cure。 Noci…association would well explain also the great functional disturbances of the viscera which immediately follow abdominal operations。
Postoperative and traumatic neuroses are at once explained on the ground of noci…association； the resulting strain from which； upon the brain…cells； causes in them physical lesions。 If one were placed against a wall and were looking into the gun muzzles of a squad of soldiers； and were told that there were nine chances out of ten that he would not be killed outright when the volley was fired； would it help him to be told that he must not be afraid？ Such an experience would be written indelibly on his brain。 This corresponds closely to the position in which some surgical patients are placed。 In railway wrecks； we can readily understand the striking difference between the after…effects in the passengers who were conscious at the time of the accident and those who were asleep or drunk。 In the latter the noci…perceptors and receptors were not aroused； hence their immunity to the nervous shock。 In the functional disturbances of the pelvic organs； association and summation may play a large role。 On this hypothesis many cases of neurasthenia may well be explained。 From the behavior of the individual as a whole we may well conclude that summation is but a scientific expression for 〃nagging。〃 Many other pathologic phenomena may be explained in a similar manner。 Thus we can understand the variations in the gastric analyses in a timid patient alarmed over his condition and afraid of the hospital。 He is integrated by fear； and as fear takes precedence over all other impulses； no organ functionates normally。 For the same reason； one sees animals in captivity pine away under the dominance of fear。 The exposure of a sensitive brain to the naked possibility of death from a surgical operation may be compared to uncovering a photographic plate in the bright sunlight to inspect it before putting it in the camera。 This principle explains； too； the physical influence of the physician or surgeon； who； by his PERSONALITY； inspires； like a Kocher； absolute confidence in his patient。 The brain； through its power of phylogenetic association； controls many processes that have wholly escaped from the notice of the 〃practical man。〃 It is in accordance with the law of association that a flower； a word； a touch； a cool breeze； or even the thought of a fishing rod or of a gun； is helpful。 On the contrary； all suggestions of despair or misfortune a corrugated brow； the gloomy silence of despair； or a doubtful word are equally depressing。 In like manner； one could add many illustrations of the symbolism that governs our daily lives。 Thus we see that through the laws of inheritance and noci…association； we are able to read a new meaning into the clinical phenomena of various diseases。
Observations on Patients whose Associational Centers are Dulled； and on Diseases and Injuries of Regions not Endowed with Nociceptors
Reversing the order of our reasoning； let us now glance at the patient who is unconscious and who； therefore； has lost much of the power of association。 His mouth is usually dry； the digestive processes are at a low ebb； the aroma of food causes no secretion of saliva； tickling the nose causes no sneezing； he catches no cold。 The laryngeal reflex is lost and food may be quietly inhaled； the entire process of metabolism is low。 The contrast between a man whose associational centers are keen and a man in whom these centers are dulled or lost is the contrast between life and death。
In accordance with the law of adaptation through natural selection； phylogeny； and association； one would expect no pain in abscess of the brain； in abscess of the liver； in pylephlebitis； in infection of the hepatic vessels； in endocarditis。 This law explains why there are no nociceptors for cancer； while there are active nociceptors for the acute infections。 It is because nature has no helpful response to offer against cancer； while in certain of the acute pyogenic infections the nociceptors force the beneficent physiologic rest。
Could we dispossess ourselves of the shackles of psychology； forget its confusing nomenclature； and view the human brain； as Sherrington has said； 〃as the organ of； and for the adaptation of nervous reaction；〃 many clinical phenomena would appear in a clearer light。
Natural Selection and Chemical Noci…association in the Infections
Thus far we have considered the behavior of the individual as a whole in his response to a certain type of noci…influences。 We have been voicing our argument in terms of physical escape from GROSS physical dangers； or of grappling with GROSS NERVE…MUSCULAR enemies of the same or of other species。 To explain these phenomena we have invoked the aid of the laws of natural selection and phylogenetic association。 If our conclusions be correct； then it should follow that in the same laws we may find the explanation of immunity； which； of course； means a defensive response to our MICROSCOPIC enemies。 There should be no more difficulty in evolving an efficient army of phagocytes by natural selection； or in developing specific chemical reactions against _*microscopic enemies_； than there was in evolving the various nociceptors for our nerve…muscular defense against our _*gross enemies_。 That immunity is a chemical reaction is no argument against the application of the law of natural selection or of association。 What essential difference is there between the chemical def
