PLATE I 



Fig. i. — The three systems of afferent, efferent, and association neurones. Spinal, cerebellar, 

 and cerebral necessary for perfect conscious voluntary movement. 



It will be observed that when a muscle contracts under the influence of voluntary stimuli from the brain, 

 alterations in tension of the skin, muscle tendon and structures of joints cause afferent impulses (kin- 

 aesthetic) to pass up to the brain. Every movement is associated with ingoing and outgoing currents. 

 The cerebellar system which is indicated by afferent and efferent systems is especially concerned with 

 reinforcement of muscular action. 



296] 



