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S. WALTER RANSON 



downward along the lateral surface of the columna posterior 

 as in the monkey; but near the surface of the cord it becomes 

 diffuse, spreading out into the fasciculus cuneatus on the one 

 hand and the lateral funiculus on the other, and fading off gead- 

 ually in either direction. The dorsal root fibers on entering the 

 cord pass through the dorso-medial portion of the tract, cutting 

 off the diffuse part of the tract in the fasciculus cuneatus. 



L.t.- 





Fig. ?} From the thir<l lumbar segment of the spinal cord of man; pyridine 

 silver technique. X 32. 



In the third thoracic segment (fig. 2) the apex represents about 

 one-half of the length of the columna posterior, and is filled by 

 the tract of Lissauer which reaches from the substantia gelati- 

 nosa to the surface of the cord. It is not well-defined on either 

 side, but does not spread out at the peri])hery of the cord as it 

 does in the third cervical segment, nor does it extend forward 



