THE AFFERENT PATHS OF SENSORY IMPULSES 875 



peduncle, the latter by way of the superior peduncle. Experiment shows 

 that after cutting the tractus spinocerebellaris dor sails a slight degree 

 of ataxia and loss of tone in the muscles innervated from below the lesion 

 may result, thus confirming the inference from the anatomical arrange- 

 ment that this tract is one of the afferent paths of cerebellar reflexes. 

 Head suggests that in their passage up the cord within the dorsal funicu- 

 lus, the primary afferent neurons concerned with the conduction of im- 

 pulses for the regulation of posture and movement give off collaterals 

 which lead part of these impulses into the direct cerebellar paths, and 

 that this is the reason why such afferent paths for deep sensibility remain 

 uncrossed until they reach the medulla. 



