MUSCLE AND MIND. 383 



fibers, make up the convolutions of the brain and constitute the 

 physical basis of the mental life.* 



The voluntary or spontaneous excitation of ideas is thus to be 

 attributed to the activity of the psycho-motor centers, while the 

 inhibitory centers, since they play an important part in attention 

 and concentration of thought, are the seat of the higher faculties ; 

 and intellectual power probably bears a direct ratio to the devel- 

 opment of these centers. By observations and experiments simi- 

 lar to those employed in localizing the sensory and motor areas, 

 the inhibitory centers have been localized in the frontal lobes of 

 the brain. The development of these lobes, as compared with 

 other parts of the brain, is conspicuous in man ; as a rule, also, 

 great intellectual power is associated with great frontal devel- 

 opment, f 



The biological doctrine that automatism is a property of proto- 

 plasm supports the theory of the originally spontaneous charac- 

 ter of the so-called voluntary movements, leading up to the view 

 that volition is an underived quality of mind ; but it is a biologi- 

 cal fact that muscles and nerves appear on the stage of animal 

 life together in the form of a reflex apparatus, and that the pri- 

 mordial movements executed by these specialized forms of proto- 

 plasm are reflex ; my fifth thesis is, therefore, that the germs of 

 volition are to be found in movements ; that volition, so far from 

 providing an original stimulus to the muscular activities, has itself 

 grown out of these activities — the voluntary movements developing 

 secondarily from reflex ones. 



Movements in themselves excite agreeable sensations which 

 prompt to repetition ; such as prove injurious, however, become a 

 source of pain which tends to their suppression — that is, to inhi- 

 bition ; volition, therefore, develops under the stimulus of pleas- 

 ure combined with the repressive influence of pain, both of which 

 result from the action of muscles. The will is thus disciplined 

 and directed to such activities as are useful to the organism. 



Prof. Meynert describes volitional impulses as due to the [re- 

 vived] perception or memory of sensations of innervation. By 

 means of association these memories acquire sufficient intensity 

 themselves to excite movements which thus starting from the brain 

 appear to be spontaneous ; their character will, however, depend 

 on what has been previously registered in the motor centers, t 

 Although the brain-centers concerned in the exercise of volun- 

 tary restraint (the inhibitory centers), primarily stimulated to 

 activity by the pain resulting from injurious movements, do not 



* " Thought consists of a certain elaboration of sensory and motor presentations, and 

 has no content apart from them." Article "Psychology," "Encyclopaedia Britannica," 

 Mr. James Ward. 



t See "Functions of the Brain," by David Ferrier, M. D., F. R. S. \ Op. tit. 



