HUMAN SPINAL CORD. 187 



necessarily large, and they may be stained by the method of Weigert, 

 or with haema. and eosin. Weigert's method requires very careful 

 manipulation, and is of more special value in pathological research. 



If human tissue cannot always be procured in suitable condition, 

 the cord of the ox, pig, sheep, cat, or rabbit will serve well. The ox, 

 especially, provides a means of securing tissue of surpassing excellence, 

 particularly for demonstration of the ganglion cells. The cord of the 

 smaller domestic animals is, in nearly every respect, as valuable for 

 study as that of man, especially as the latter cannot usually be gotten 

 before the serious putrefactive changes, to which nerve tissue is prone, 

 have made marked progress. 



HUMAN SPINAL COED. CERVICAL REGION. 



TRANSVERSE SECTION. (Fig. 122.) 



OBSERVE: 

 (L.) 



1. General arrangement of gray and white substance, with 

 the latter surrounding the former, which resembles in outline the 

 letter H. 



2. Subdivisions of white substance, (a) Anterior median fis- 

 sure. (Note its passage inward and its cessation before reaching the 

 gray substance.) (b) Posterior median fissure. (Note its shallowness 

 as a true fissure, and the extension of the connective tissue from the 

 bottom inward, until the gray substance is met. Compare the two 

 median fissures.) (c) The emergence of the anterior nerve-roots. 

 (This provides the external or lateral boundary of anterior white 

 columns or direct pyramidal tracts, the internal boundaries being 

 provided by the anterior median fissure.) (d) The lateral columns. 

 (These contain the fibres of the crossed pyramidal tract, and include 

 the white substance between the anterior nerve-roots and the posterior 

 gray cornu. Each lateral column contains nerve fibres which pass to 

 the cerebellum direct cerebellar tract; observe that these tracts have 

 no internal histological boundary. Note the numerous prolongations 

 of the pia mater inward in the lateral columns.) (e) The postero- 

 internal or column of Goll -funiculus graoilis. (These columns 

 present on either side of the posterior median fissure, and are bounded 

 laterally by a prolongation from the pia mater.) (/) The postero- 

 external columns -funiculus cuneatus. (Bounded internally by 

 the postero-internal columns, and externally by the posterior gray 

 cornua.) (g) The white commissure. (Note the absence of a white 

 commissure posteriorly, the posterior median septum reaching the 

 .gray substance.) 



