360 THE SPINAL CORD, BY J. GERLACH. 



connected with these cell groups. On one occasion two fasci- 

 culi were given off from their anterior border, of which one, 

 curving round, ran backwards (fig. 228, /), whilst the other 

 entered the lateral columns externally, and decussated with a 

 third fasciculus that proceeded from the centre of Clarke's 

 group, and also ran to the side (fig. 228, g). If a precisely 

 analogous arrangement of these fasciculi does not obtain 

 throughout the entire length of the dorsal portion of the 

 cord, fasciculi running backwards and outwards nevertheless 

 arise through the whole extent of this region, from the columns 

 of Clarke, with the further relations of which I am unac- 

 quainted ; perhaps these, running backwards, enter the posterior 



Fig. 228. 



Fig. 228. Middle part of a transverse section of the spinal cord of 

 a Child. Gold-tinted preparation. Magnified 50 diameters, a, 

 Lateral column ; b, posterior column ; c, one half of the central canal ; 

 d, sections of vessels ; e, Clarke's column ; /, fibres from Clarke's co- 

 lumn, running backwards ; g, decussation of the fasciculi passing out 

 wards ; /i, laterally situated nerve cells of variable size. 



roots of the nerves. The remainder of the central portion of 

 the cord resembles histologically those parts of the anterior 

 cornua that are free from cells, except that, posteriorly and 

 internally, ascending fibres occur in the grey substance, from 

 which small fasciculi extend into the grey commissure, where 

 they traverse the lateral parts of the posterior transverse 

 fibres. Externally, especially in the cervical portion of the 

 spinal cord, the line of demarcation between the grey and 

 white substance is less sharply drawn than elsewhere, fasciculi 

 of the lateral columns lying more or less deeply imbedded in 

 the grey substance, and leading to the formation of the so-called 

 reticular structure (formatio reticularis). 



