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STUDENTS HISTOLOGY 



boundary of the anterior white columns, the internal boundaries 

 being provided by the anterior median fissure.) (d) The lateral 

 columns. (These contain the fibers of the crossed pyramidal tract, 

 and include the white substance between the anterior nerve -roots 

 and the posterior gray cornua. Each lateral column contains 

 nerve-fibers which pass to the cerebellum direct cerebellar tract ; 

 observe that these tracts have no internal histological boundary. 

 Note the numerous prolongations of the pia mater inward in the 

 lateral columns and blood-vessels in them, (e) The postero-in- 



PIG. 149. TRANSVERSE SECTION OP THE SPINAL, CORD. MIDDLE CERVICAL 



REGION (X 60). 



A. Anterior. B. Posterior. 



This section was made from the cord of a man who died at the age of 75 years, from 

 senile dementia. The gray substance appeared normal, but of somewhat diminished area. 



ternal or column of Gollfuniculus gracilis. (These columns 

 occur on either side of the posterior median fissure, and are 

 bounded laterally by a prolongation from the pia mater.) (/) 

 The postero-external column funiculus cuneatus. (Bounded 

 internally by the postero- internal column, and externally by the 

 posterior gray cornu.) (0r) The white commissure. (Note the 



