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VETERINAKY PHYSIOLOGY 



receiving mechanism, to (2) loss of the mechanism causing the 

 movements, or (3) to interruption of the channels between them. 

 Again, it is quite possible that, after removing the receiving 

 mechanism in the cerebrum, external stimuli may lead to 

 the usual response by acting through lower reflex arcs (fig. 98). 

 If, for instance, we suppose the receiving part of the cerebrum 

 connected with the reception of tactile impressions entirely 

 destroyed, scratching the sole of the foot may still cause the 



FIG. 99. Left Hemisphere of Brain of Chimpanzee to show the results of 

 stimulating different parts. The Sulcus Centralis is the fissure of 

 Rolando. (From GKUNBAUM and SHERRINGTON.) 



leg to be drawn up, just as if a sensation had been experienced. 

 Here although the upper arc is out of action the lower arc 

 still acts. 



In the lower animals, stimulation of a part of the brain, 

 if it be connected with the reception of impressions, may 

 cause the series of movements which naturally follow such 

 an impression. But these movements may also be caused 

 by directly stimulating the reacting mechanism. When, 

 however, removal of a part of the brain causes no loss of 

 power of movement, and yet prevents a stimulus from 



