467 



SCIENTIFIC SIDE-LIGHTS 



Movement 

 Movements 



circumnutating movement being increased 

 in some one direction. The leaves of 

 various plants are said to sleep at night, 

 and it will be seen that their blades 

 then assume a vertical position through 

 modified circumnutation, in order to pro- 

 tect their upper surfaces from being 

 chilled through radiation. The movements 

 of various organs to the light, which are so 

 .general throughout the vegetable kingdom, 

 and occasionally from the light, or trans- 

 versely with respect to it, are all modified 

 forms of circumnutation, as again are the 

 equally prevalent movements of stems, etc., 

 towards the zenith, and of roots towards 

 the center of the earth. DARWIN Power of 

 Movement in Plants, ch. 1, p. 3. (A., 1900.) 



2288. MOVEMENTS, AUTOMATIC 



Education Makes Reflex Action Habitual 

 <ind Easy Superfluous Activity Eliminated. 

 In our first attempts to write, to cipher, 

 to play on an instrument, to speak, or in 

 any other work of mechanical skill, the in- 

 ward sense of labor and difficulty is corre- 

 sponded to by the number of awkward and 

 irrelevant gesticulations. On the other hand, 

 in the last stage of consummated facility 

 and routine, the consciousness is almost 

 nothing; and the general quietude of the 

 body demonstrates that the course of power 

 lias now become narrowed to the one 

 channel necessary for the exact movements 

 required. This is a sort of educated imita- 

 tion of the primitive reflex movement ad- 

 duced at the outset; the comparison is so 

 striking as to suggest to physiologists the 

 designation of secondary reflex or automat- 

 ic for the habitual movements. A man at 

 a signal-post, after long habit, is subjected 

 to little or no nervous influence, except in 

 the single thread of connection between a 

 certain figure depicted on the eye and a cer- 

 tain movement of the hand; the collaterals 

 of the primitive wave have died away, and 

 the accompanying consciousness has fallen 

 to a barely discernible trace. BAIN Mind 

 and Body, ch. 4, p. 14. (Hum., 1880.) 



2289. Mental Association 



Tends to Repeat Itself Greek Verbs 

 Learned by Hearing Recitation. A series 

 of movements repeated in a certain order 

 tend to unroll themselves with peculiar ease 

 in that order forever afterward. Num- 

 ber one awakens number two, and that awa- 

 kens number three, and so on, till the last 

 is produced. A habit of this kind once be- 

 come inveterate may go on automatically. 

 And so it is with the objects with which 

 our thinking is concerned. With some per- 

 sons each note of a melody, heard but once, 

 will accurately revive in its proper sequence. 

 Small boys at school learn the inflections 

 of many a Greek noun, adjective, or verb 

 from the reiterated recitations of the upper 

 classes falling on their ear as they sit at their 

 desks. All this happens with no voluntary 

 effort on their part, and with no thought 



of the spelling of the words. JAMES Psy- 

 chology, vol. i, ch. 14, p. 554. (H. H. & 

 Co., 1899.) 



229O. Muscular Activities 



Repressed or Reenforced by Volition Fa- 

 tigue Requires Exertion of the Will. Each 

 individual movement [in walking] suggests 

 the succeeding one, and the repetition 

 continues until, the attention having been 

 recalled, the automatic impulse is super- 

 seded by the control of the will. Further, 

 the direction of the movement is given by 

 the sense of sight, which so guides the 

 motions of our legs that we do not jostle 

 our fellow passengers or run up against 

 lamp-posts ; and the same sense directs 

 also their general course along the line 

 that habit has rendered most familiar, 

 altho at the commencement of our walk we 

 may have intended to take some other. Sup- 

 pose our walk to be so prolonged, however, 

 that the sense of fatigue comes on before 

 we have reached its appointed conclusion. 

 This calls off our attention from what is 

 going on in the mind to the condition of the 

 body; and in order to sustain the move- 

 ments of locomotion a distinct exertion of 

 the will comes to be requisite for each. 

 With the increasing sense of fatigue an in- 

 creased effort becomes necessary, and at last 

 even the most determined volition may find 

 itself unable to evoke a respondent move- 

 ment from the exhausted muscles. CARPEN- 

 TER Mental Physiology, bk. i, ch. 1, 16, p. 

 18. (A., 1900.) 



2291. Voluntary and In- 

 voluntary Activity Combined Walking, Run- 

 ning, Writing, Etc., Done Chiefly by Reflex 

 Action Volition May Become a Hindrance. 

 Reflex acts performed under the influence 

 of the reflecting power of the spinal cord 

 are essentially independent of the brain, and 

 may be performed perfectly when the brain 

 is separated from the cord. [It may be af- 

 firmed] that these include a much larger 

 number of the natural and purposive move- 

 ments of the lower animals than of the 

 warm-blooded animals and man ; and that 

 over nearly all of them the, mind may exer- 

 cise, through the higher nerve-centers, some 

 control, determining, directing, hindering, 

 or modifying them, either by direct action, 

 or by its power over associated muscles. 



To these instances of spinal reflex action 

 some add yet many more, including nearly 

 all the acts which seem to be performed 

 unconsciously, such as those of walking, 

 running, writing, and the like, for these 

 are really involuntary acts. It is true that 

 at their first performances they are volun- 

 tary, that they require education for their 

 perfection, and are at all times so constantly 

 performed in obedience to a mandate of the 

 will that it is difficult to believe in their 

 essentially involuntary nature. But the 

 will really has only a controlling power 

 over their performance; it can hasten or 

 stay them, but it has little or nothing to 



