176 



LECTURES ON THE CENTRAL NERVOUS SYSTEM. 



The above-mentioned functions are the very ones that suffer most in a 

 dilation of the central canal syringomyelia or in tumors which are frequently 

 situated in the midst of the gray matter. 



After this short excursion into the domain of pathology let 

 us return to the consideration of the structure of the spinal 



cord. At its up- 

 per end the white 

 fibres which com- 

 pose it are arranged 

 in a most intricate 

 manner. The ex- 

 tent and form of 

 the gray matter is 

 markedly changed, 

 new collections of 

 glia- and ganglion- 

 cells appear, and the 

 familiar appearance 

 of a section through 

 the spinal 

 greatly 



The resemblance is 

 particularly hard to 

 trace just above 

 the upper terminus 

 of the spinal cord, 

 where the inferior 

 olivary body, a gray, 

 plicated lamina, rich 

 in ganglion-cells, 

 usurps the place of 

 the lateral columns on each side, and the central canal, trending 

 continually backward, expands into the fossa rhomboidalis. 



The series of sections which I will now demonstrate to you 

 is intended to elucidate the transition of the spinal cord into the 

 medulla oblongata. 



& 1 

 cord is 



changed. 



FIG. 105 A AND B. 



Spinal cord, with acute anterior poliomyelitis, 43 years after 

 the commencement of the disease. A. Section through the lum- 

 bar enlargement, both anterior horns and both antero-lateral 

 columns strongly atrophied, more so on the left than on the 

 right. No ganglion-cells. B. Section through the cervical en- 

 la! gement. Left anterior horn and antero-lateral column 

 markedly atrophied, and without ganglion-cells. Posterior 

 horns and columns normal in both sections. (After Charcot 

 and Joffroy. ) 



