TRACT OF LISSATER 



109 



8 9 



Fig. 8 From the fifth cervical segment of the spinal cord of the monkey 

 (^Nlacacus rhesus) ; Pal-Weigert technique; a small area of the tract of Lissauer 

 showing medullated fibers. X 1160. 



Fig. 9 From the seventh cervical segment of the spinal cord of the monkey 

 (^lacacus rhesus) ; pyridine-silver technique; a small area of the tract of Lissauer 

 showing medullated and non-meduUated axons. X 1100. 



horizontal fibers just mentioned. One fiber was followed from 

 the root more than halfway to the substantia gelatinosa. It is 

 probable that others of these medullated dorsal root fibers go to 

 form vertical fibers in the tract. 



In that part of the tract w^hich extends \^entrally along the 

 lateral surface of the columna posterior there are a few large 

 medullated fibers; but the small and medium-sized ones are 

 more widely scattered than in the dorsal portion of the tract so 

 that this region takes an even lighter stain than the dorsal por- 

 tion. There are in this lateral i:)ortion a very few oblique fil)ers, 

 so few that they are practically negligible. On carefully looking 

 through a number of preparations I was unable to see a sin'jje 



