PRIMARY DEGENERATIONS OF THE CORD. 433 



alterations is not fully understood. By a majority of pathol- 

 ogists, however, they are regarded as secondary to disease of 

 the posterior roots or their ganglion-cells. By many, syphilis 

 is regarded as the most frequent cause of this condition. 



Macroscopically, in well-advanced cases the cord usually 

 appears atrophied, especially in the region of the posterior 

 white columns, which are narrow and sunken, and gray or 

 grayish-yellow in color (Figs. 203 and 204). On trans- 



FIG. 205. 



&. J 



Section of spinal cord about the eighth dorsal segment (from a case of locomotor 

 ataxia). There is sclerosis of the postero-external column and atrophy of the 

 fine plexus of nerve-fibrils surrounding the cells of Clarke's column ; moreover, 

 a band of sclerosis is seen entering the column instead of the bundle of nerve- 

 fibres. The cells themselves are atrophied and their processes destroyed. This 

 case was of interest because, in connection with these lesions, the patient had 

 well-marked visceral symptoms gastric crises, bladder troubles, and laryngeal 

 crisis in addition to the ordinary ataxic symptoms. X 100 diameters (F. W. 

 Mott). 



verse section these changes are found to be most marked in 

 the lumbar or dorsal regions the central gray matter is not 

 generally affected. 



28 Hist. 



