COURSE OF NERVE-FIBRES. 



Fig. 20. DIAGRAM SHOWING THK PRO- 

 BABLE RELATIONS OF SOME OF THK 

 PRINCIPAL CELLS AND FIBRES OF 

 THE CEREBRO-SPINAL SYSTEM TO ONE 

 ANOTHER. (E.A.S.) 



1, a cell of the cortex cerebri ; 2, its 

 axis-cylinder or nerve-process passing 

 down in the pyramidal tract, and giving 

 off collaterals, some of which, 3, 3, end 

 in arborisations around cells of the ante- 

 rior horn of the spinal cord, the main 

 fibre having a similar ending at 4 ; call. , 

 a collateral passing in the corpus callosum 

 to the cortex of the opposite side ; sir. , a 

 collateral passing into the corpus stria- 

 turn ; 5, axis-cylinder process of anterior cornu-cell passing to form a terminal arborisation in the end- 

 plate of a muscle-fibre, m. 



6, a cell of one of the spinal ganglia. Its axis-cylinder process bifurcates, and one branch, 7, passes 

 to the periphery to end in an arborisation in the sensory surface, . The other (central) branch bifurcates 

 after entering the cord (at 8), and its divisions pass upwards and downwards (the latter for a short 

 distance only) ; 9, ending of the descending branch in a terminal arborisation around a cell of the 

 posterior horn, the axis-cylinder process of which, again, ends in a similar arborisation around a cell of 

 the anterior horn ; 10, a collateral passing from the ascending division directly to envelop a cell of the 

 anterior horn ; 11, one passing to envelop a cell of Clarke's column ; 12, a collateral having connections 

 like those of 9 ; 13, ending of the ascending division of the posterior root-fibre around one of the cells of 

 the posterior columns of the bulb ; 14, 14, axis-cylinder processes of cells of the posterior horn passing 

 to form an arborisation around the motor cells ; 15, a fibre of the ascending cerebellar tract passing up 

 to form an arborisation around a cell of the cerebellum ; 16, axis-cylinder process of this cell passing 

 down the bulb and cord, and giving off collaterals to envelop the cells of the anterior horn ; 17, axis- 

 cylinder process of one of the cells of the posterior column of the bulb passing as a fibre of the fillet to 

 the cerebrum, and forming a terminal arborisation around one of the smaller cerebral cells ; 18, axis- 

 cylinder process of this cell, forming an arborisation around the pyramidal-cell, 1. 



