the expression of emotion in man and animals-第7部分
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sleep； and therefore cannot be due to imitation； but must be altogether natural。 The particulars are perfectly trustworthy； for I have enquired fully into them； and speak from abundant and independent evidence。 A gentleman of considerable position was found by his wife to have the curious trick； when he lay fast asleep on his back in bed； of raising his right arm slowly in front of his face； up to his forehead； and then dropping it with a jerk； so that the wrist fell heavily on the bridge of his nose。 The trick did not occur every night； but occasionally； and was independent of any ascertained cause。 Sometimes it was repeated incessantly for an hour or more。 The gentleman's nose was prominent； and its bridge often became sore from the blows which it received。 At one time an awkward sore was produced； that was long in healing； on account of the recurrence； night after night； of the blows which first caused it。 His wife had to remove the button from the wrist of his night…gown as it made severe scratches； and some means were attempted of tying his arm。
〃Many years after his death； his son married a lady who had never heard of the family incident。 She； however； observed precisely the same peculiarity in her husband； but his nose； from not being particularly prominent； has never as yet suffered from the blows。 The trick does not occur when he is half…asleep； as； for example； when dozing in his arm…chair； but the moment he is fast asleep it is apt to begin。 It is； as with his father； intermittent； sometimes ceasing for many nights； and sometimes almost incessant during a part of every night。 It is performed； as it was by his father； with his right hand。
〃One of his children； a girl； has inherited the same trick。 She performs it； likewise； with the right hand； but in a slightly modified form； for； after raising the arm； she does not allow the wrist to drop upon the bridge of the nose； but the palm of the half…closed hand falls over and down the nose； striking it rather rapidly。 It is also very intermittent with this child； not occurring for periods of some months； but sometimes occurring almost incessantly。〃 ｛end of long footnote｝
Another curious instance of an odd inherited movement； associated with the wish to obtain an object； will be given in the course of this volume。
There are other actions which are commonly performed under certain circumstances； independently of habit； and which seem to be due to imitation or some sort of sympathy。 Thus persons cutting anything with a pair of scissors may be seen to move their jaws simultaneously with the blades of the scissors。 Children learning to write often twist about their tongues as their fingers move； in a ridiculous fashion。 When a public singer suddenly becomes a little hoarse； many of those present may be heard； as I have been assured by a gentleman on whom I can rely； to clear their throats； but here habit probably comes into play； as we clear our own throats under similar circumstances。 I have also been told that at leaping matches； as the performer makes his spring； many of the spectators； generally men and boys； move their feet； but here again habit probably comes into play； for it is very doubtful whether women would thus act。
_Reflex actions_Reflex actions； in the strict sense of the term； are due to the excitement of a peripheral nerve； which transmits its influence to certain nerve…cells； and these in their turn excite certain muscles or glands into action； and all this may take place without any sensation or consciousness on our part； though often thus accompanied。 As many reflex actions are highly expressive； the subject must here be noticed at some little length。 We shall also see that some of them graduate into； and can hardly be distinguished from actions which have arisen through habit？ Coughing and sneezing are familiar instances of reflex actions。 With infants the first act of respiration is often a sneeze； although this requires the co…ordinated movement of numerous muscles。 Respiration is partly voluntary； but mainly reflex； and is performed in the most natural and best manner without the interference of the will。 A vast number of complex movements are reflex。 As good an instance as can be given is the often…quoted one of a decapitated frog； which cannot of course feel； and cannot consciously perform； any movement。 Yet if a drop of acid be placed on the lower surface of the thigh of a frog in this state； it will rub off the drop with the upper surface of the foot of the same leg。 If this foot be cut off； it cannot thus act。 〃After some fruitless efforts； therefore； it gives up trying in that way； seems restless； as though； says Pfluger； it was seeking some other way； and at last it makes use of the foot of the other leg and succeeds in rubbing off the acid。 Notably we have here not merely contractions of muscles； but combined and harmonized contractions in due sequence for a special purpose。 These are actions that have all the appearance of being guided by intelligence and instigated by will in an animal； the recognized organ of whose intelligence and will has been removed。〃＇10＇
＇9＇ Prof。 Huxley remarks （‘Elementary Physiology；' 5th edit。 p。 305） that reflex actions proper to the spinal cord are NATURAL； but； by the help of the brain； that is through habit； an infinity of ARTIFICIAL reflex actions may be acquired。 Virchow admits （‘Sammlung wissenschaft。 Vortrage；' &c。； 〃Ueber das Ruckeninark；〃 1871； ss。 24； 31） that some reflex actions can hardly be distinguished from instincts； and； of the latter； it may be added； some cannot be distinguished from inherited habits。
We see the difference between reflex and voluntary movements in very young children not being able to perform； as I am informed by Sir Henry Holland； certain acts somewhat analogous to those of sneezing and coughing； namely； in their not being able to blow their noses （i。 e。 to compress the nose and blow violently through the passage）； and in their not being able to clear their throats of phlegm。 They have to learn to perform these acts； yet they are performed by us； when a little older； almost as easily as reflex actions。 Sneezing and coughing； however； can be controlled by the will only partially or not at all； whilst the clearing the throat and blowing the nose are completely under our command。
＇10＇ 〃Dr。 Maudsley； ‘Body and Mind；' 1870； p。 8。
When we are conscious of the presence of an irritating particle in our nostrils or windpipethat is； when the same sensory nerve…cells are excited； as in the case of sneezing and coughing we can voluntarily expel the particle by forcibly driving air through these passages； but we cannot do this with nearly the same force； rapidity； and precision； as by a reflex action。 In this latter case the sensory nerve…cells apparently excite the motor nerve…cells without any waste of power by first communicating with the cerebral hemispheresthe seat of our consciousness and volition。 In all cases there seems to exist a profound antagonism between the same movements； as directed by the will and by a reflex stimulant； in the force with which they are performed and in the facility with which they are excited。 As Claude Bernard asserts； 〃L'influence du cerveau tend donc a entraver les mouvements reflexes； a limiter leur force et leur etendue。〃＇11＇
The conscious wish to perform a reflex action sometimes stops or interrupts its performance； though the proper sensory nerves may be stimulated。 For instance； many years ago I laid a small wager with a dozen young men that they would not sneeze if they took snuff； although they all declared that they invariably did so； accordingly they all took a pinch； but from wishing much to succeed； not one sneezed； though their eyes watered； and all； without exception； had to pay me the wager。 Sir H。 Holland remarks＇12＇ that attention paid to the act of swallowing interferes with the proper movements； from which it probably follows； at least in part； that some persons find it so difficult to swallow a pill。
＇11＇ 〃See the very interesting discussion on the whole subject by Claude Bernard； ‘Tissus Vivants；' 1866； p。 353…356。
＇12＇ ‘Chapters on Mental Physiology；' 1858； p。 85。
Another familiar instance of a reflex action is the involuntary closing of the eyelids when the surface of the eye is touched。 A similar winking movement is caused when a blow is directed towards the face； but this is an habitual and not a strictly reflex action； as the stimulus is conveyed through the mind and not by the excitement of a peripheral nerve。 The whole body and head are generally at the same time drawn suddenly backwards。 These latter movements； however； can be prevented； if the danger does not appear to the imagination imminent； but our reason telling us that there is no danger does not suffice。 I may mention a trifling fact； illustrating this point； and which at the time amused me。 I put my face close to the thick glass…plate in front of a puff…adder in the Zoological Gardens； with the firm determination of not starting back if the snake struck at me； but； as soon as the blow was struck； my resolution went for nothing； and I jumped a yard or two backwards with astonishing rapidity。 My will and reason were powerless against the imagination of a danger which had never been experienced。
The violence of a start seems to depend partly on the vividness of the imagination； and partly on the condition； either habitual or temporary； of the nervous system。 He who will attend to the starting of his horse； when tired and fresh； will perceive how perfect is the gradation from a mere glance at some unexpected object； with a momentary doubt whether it is dangerous； to a jump so rapid and violent； that the animal probably could not voluntarily whirl round in so rapid a manner。 The nervous system of a fresh and highly…fed horse sends its order to the motory system so quickly； that no time is allowed for him to consider whether or not the danger is real。 After one violent start； when he is excited and the blood flows freely through his brain； he is very apt to start again； and so it is； as I have noticed； with young infants。
A start from a sudden noise； when the stimulus is conveyed through the auditory nerves； is always acco
