100 S. WALTER RANSON 



of the rat and rabbit, we have succeeded in improving our prep- 

 arations by a preliminary injection of ammoniated alcohol, as 

 suggested by Huber ('13), but in other cords, especially those of 

 the cat and monkey, excellent results can be secured without 

 preliminary injection. 



The pyridine-silver material was imbedded in paraffin and cut 

 into sections 5 to 12 microns thick. The Pal-Weigert cellodin 

 sections were 12 to 24 microns thick. 



LISSAUER'S TRACT IN MAN 



Parts of four apparently normal cords were obtained for me 

 from autopsies on bodies which had been dead for two, three, 

 six and twelve hours, respectively. The approximate levels of 

 the sections were determined by reference to Marburg's Atlas, 

 comparing the shape of the white and gray columns with that 

 characteristic for each segment. In the third cervical segment 

 (fig. 1) the gray substance proper, capped by the sharply pointed 

 substantia gelatinosa, occupies about two-thirds of the columna 

 posterior. The remaining one-third, the apex, is occupied by 

 Lissauer's tract. In contrast to what is seen in the cat, the tract 

 is not sharply limited either toward the fasciculus cuneatus or 

 the lateral funiculus. It shows, however, no tendency to spread 



ABBREVIATIONS 



The following is a list of abbreviations used on all the drawings: 



c.c, eanalis centralis l.p.p.r., lateral part of posterior root 



c.p., columna posterior L.t., Lissauer's ti'act 



e.r.z., entering root zone n., neuroglia 



f.c, fasciculus cuneatus P-'>'-, ring of pia constricting the enter- 

 f.cs., fasciculus cerebellospinalis ing root 



f.l., funiculus lateralis r.p., radix posterior 



i.l., intermediate layer s.g.R., substantia gelatinosa Rolandi 

 I.e. L.t., lateral expansion of Lissauer's s.z., stratum zonale 

 tract 



Fig. 1 From the third cervical segment of the spinal cord of man; i)yridine- 

 silver technique. X 32. 



Fig. 2 From the third thoracic segment of the spinal cord of man; pyridine- 

 silver technique. X 32. 



