KH) 



S. WALTER RANSON 



is a considerable intermingling of the fibers of the two fascicles. 

 On the side toward the lateral funiculus there is a neuroglia sep- 

 tum which extends into the cord, separating the tract in question 

 from the cerebellospinal fasciculus. The septum does not, how- 

 ever, reach the gray substance, and ventrally to it the tract of 

 Lissauer spreads out into the lateral funiculus upon the lateral 

 surface of the coknnna posterior. It goes over gradually into 

 the fasciculus proprius of the lateral funiculus. The entering 



S q.R 



l.elt: 



Fig. 6 From the fifth lumbar segment of the spinal cord of the monkey 

 (Macacus rhesus); pyridine-silver technique. X 32. 



dorsal root bundles pass over the tip of the tract of Lissauer to 

 enter the cord on its medial side. A few fibers are usually cut 

 off from the main part of the tract by the entering radicles and 

 form a small ))imdle in the dorso-lateral angle of the cuneate 

 fasciculus. 



In the thoracic region of the monkey cord (fig. 5, seg. T. 8.) the 

 columna posterior is very short, and is almost completely cov- 

 ered by the substantia gelatinosa. The main part of the tract 

 of Lissauer extends dorsalward from the substantia gelatinosa as 



