CH. XLIL] 



COURSE OF FIBRES IN CORD. 



611 



arborescence in the skin (S); the arrow by the side of this branch 

 represents the direction of conduction of the sensory impulses 

 from the skin. An arrow in the opposite direction would indicate 

 the direction of its growth. The other branch C passes into the 

 spinal cord, where it again bifurcates ; the branch E, a short one, 

 passes downwards and ends in an arborisation around one of the 

 small cells P : of the posterior cornn ; from which a new axis- 



M 



Fig. 453. Course of nerve-fibres in spinal cord. (After Sch&fer.) 



cylinder arises, and terminates around one of the multipolar 

 cells (4) of the anterior horn. 



The main division D travels up in the posterior column of the 

 cord, and ends in grey matter at various levels. Some collaterals 

 (5) terminate by arborising directly around the anterior cornual 

 cells, principally of the same side ; others (6) do so with an inter- 

 mediate cell station in a posterior cornual cell P 2 ; others (7) 

 arborise around the cells of Clarke's column (C) in the thoracic 

 region of the cord, and from these cells fresh axis-cylinders carry 

 up the impulse to the cerebellum in what is called the direct 

 cerebellar tract, while the main fibre (8) may terminate in any of 

 these ways at a higher level in the cord, or above the cord in 



a B 2 



