496 THE FUNCTIONAL RELATIONS OF THE 



'ingoing currents' in all kinds of nerve centres. On the 

 other hand, we were led to regard the phenomena of the 

 * outgoing current ' as non-mental, and the regions of the 

 nervous system concerned therewith as not strictly con- 

 stituting parts of the ' Organ of Mind.' 



Certain it is that directly we pass from the purely 

 mental side, or from the starting-points of a Volition, we 

 find two main pathways by which its associated stimuli (in 

 the form of molecular movements), may pass away from 

 the cortex of the Cerebral Hemispheres to Muscles on 

 each side of the body. 



The muscles of the right or left limbs, or such groups 

 of them in other parts as are usually called into action 

 independently of their fellows on the opposite side of the 

 body, receive their ' volitional ' stimuli, as we have stated, 

 only through the Cerebral Hemisphere of the opposite 

 side. But bilaterally situated muscles that habitually 

 act together, may be stimulated indifferently from either 

 Hemisphere (Broadbent), owing to the existence of inti- 

 mate commissural connections, binding together the du- 

 plicate Spinal Centres in relation with such muscles so 

 closely as to make each pair in effect one Centre. 



A highly important exception to this latter rule seems 

 to exist, however, in the case of the bilaterally acting 

 muscles concerned in the Articulation of Words — that is, 

 in ordinary Speech. Usually the stimulus that passes 

 over from the Cortex to incite these muscular acts issues 

 from one Cerebral Hemisphere only, and in the great 

 majority of cases the Left Hemisphere is the source of 

 Buch Speech-incitations. The proof of these statements, 

 and further particulars in regard to the paths of outgoing 

 stimuli generally, will be given in subsequent chapters. 



