334 



PRACTICAL HISTOLOGY. 



[XXX. 



cord is thus almost completely divided into two symmetrical halves 



(fig- 314). 



(c.) If the section is made at the level of the origin of the 

 nerve-roots, these may be seen. The mode of origin of some of the 

 fibres of these roots can always be seen. The anterior root passes 



A.M.F 



P.M.F 



FlG. 314. T.S. Lower Dorsal Cord, Human. A. L, P. Anterior, lateral, and posterior 

 columns; A.M.F , P.M.F. Anterior and posterior median fissures; a, b, c. Nerve- 

 cells of the anterior horn; d Posterior cornu and substantia gelatinosa; e. Central 

 canal ; /. Veins , g. Origin of anterior nerve-root ; h. Posterior nerve-root ; i. White, 

 and j. Grey commissures ; if. Reticular formation. 



out of the cord in several bundles, while the posterior root enters 

 the cord in one compact bundle. 



(d.) The white matter externally, and the grey matter internally, 

 the latter deeply stained. The origin of the nerve-roots dividing 

 the white matter into the anterior, lateral, and posterior columns, 

 but owing to the anterior root leaving the cord in several bundles, 

 there is not an exact anatomical limitation of the anterior from the 

 lateral column. 



(e.) The grey matter, deeply stained a crescentic mass in each 

 half of the cord, with a broader anterior cornu, with numerous 



