586 WILL AND 



evoke similar Movements. But would such facts entitle 

 us to infer that these Sensory Ganglia contain 'motor' 

 Centres ? Assuredly not : no more than we should 

 be entitled to call the ' sensory cells ' on the ingoing side 

 of a simple mechanism for some lleflex Action ' motor 

 t^ells/ simply because a stimulus issues from them which 

 ultimately evokes the Movement that is, after it has 

 passed through other nerve elements which, by common 

 consent, are regarded as ' motor cells.' 



The nervous fibres that extend from the Cerebral 

 Cortex, in higher animals and in Man, down to the 

 Corpora Striata are, in their nature, strictly comparable 

 with the fibres connecting the ' sensory ' and the ' motor' 

 Cells in an ordinary nervous mechanism for Reflex 

 Action. Such currents from ' sensory ' cells may pass in 

 the same horizontal plane, they may have to ascend, or, 

 as frequently happens, they may descend to ' motor ' cells 

 situated at a lower level.* 



The Corpora Striata, conjointly with the Cerebellum, 

 are doubtless specially called into activity by the Cere- 

 bral Cortex, in ways which are most important though 

 they cannot be precisely defined. These organs, as we 



* On account of the variability of this relation, therefore, such 

 nerve fibres cannot be considered to be invariably in relation either 

 with ' ingoing ' or with ' outgoing ' currents. We may distinguish 

 them by the name of ' iuternuncial fibres,' with the understanding 

 that in different parts of the Nervous System currents are trans- 

 mitted along them in an ascending, a horizontal, or in a descending 

 direction. Still, as the stimuli emanating from the Sensory 

 Centres and their annexes in the Cerebral Cortex, at once take a 

 downward direction to the Corpora Striata, it will be most con- 

 venient in this case, to speak of the origin of ' outgoing ' currents 

 as being from the Cerebral Cortex itself, and to regard certain of 

 its Centres as occupying what has been aptly termed the ' bend of 

 the stream ' that is the regions where ' ingoing ' currents end or 

 give place to ' outgoing ' currents. 



