474 



THE NERVOUS SYSTEM. 



9. Poster olateralj also called column of 33urdach, which is con- 

 tinuous with the fuiiiculus cuneatus. 



10. Comma tract. 



The position and relation of these tracts can be better under- 

 stood by reference to the illustrations than by any verbal descrip- 

 tion. 



Grouping of the Nerve-cells (Fig. 274). Some of the 

 nerve-cells of the cord are distributed through the gray matter, 

 while others are arranged in groups, the latter being larger, and 

 characterized by their branching ; they are multipolar nerve-cells. 



Cells of the Anterior Horn. In the anterior cornu are three of 

 these groups: 1. Near the tip on the inner side; 2. At the base 

 on the inner side ; and 3. On the outer side of the gray matter. 



Posterior horn T~ 



cell. 



Crossed pyram- 

 idal column. 

 Golgi cell of 

 posterior horn. 

 Direct cerebel 

 lar column. 

 Column cells. 



Golgi's com mis- 

 sural cells. 

 Gowers' col-*.-' 



umn. 

 Motor cells. N 



Collaterals 

 ending in 

 the gray 

 matter. 



Direct pyramidal column. 



FIG. 274. Schematic diagram of the spinal cord in cross-section, after von 

 Lenhossek, showing in the left half the cells of the gray matter, in the right half 

 the collateral branches ending in the gray matter (Bohm and Davidoff ). 



Each cell of the anterior cornu gives off an axis-cylinder process 

 which passes out into the anterior nerve-roots. 



Cells of the Posterior Horn. These are smaller than those of 

 the anterior cornu, but their axis-cylinder processes do not pass 

 into the posterior nerve-roots. 



Clarke's Column. This group of cells is most marked in the 

 thoracic region, and is situated at the base of the posterior cornu. 

 Their axis-cylinder processes pass into the direct cerebellar tract. 



Intermediolateral Tract. This group is situated on the outer 

 side of the gray matter in what is called the lateral horn between 

 the anterior and posterior cornua. 



Middle Cell-group. These He in the middle of the crescent. 



Nerve-fibers of the Gray Matter. These are, as a rule, 

 smaller than those in the white substance. In the posterior cornu 



