30G ELEMENTARY PHYSIOLOGY. [XXIX. 



g. In the lumbar region, the nerve fibres of the 

 anterior root spreading out in the grey sub- 

 stance, some may be seen running across to 

 the other side of the cord and forming part 

 of the anterior white commissure (the course 

 of the fibres of the anterior root is the same 

 in the other regions of the cord but usually 

 less distinct). 



The Student should be able to recognize a sec- 

 tion of the spinal cord as belonging to the cervi- 

 cal, the dorsal or lumbar region ; in doing this, 

 the chief points to be noticed are : the presence 

 or absence of Goll's column, of the tractus inter- 

 medio-lateralis (lateral cornu), and of the collec- 

 tion of cells forming Clarke's column ; the 

 relative amount of white and of grey substance ; 

 the shape of the anterior and of the posterior 

 cornu ; and the position of the central canal. 



5. Place a short piece of the spinal cord of an ox 

 in potassium bichromate *2 p.c. for a few days, 

 and after the chromium salt has been removed 

 by 30 p.c. alcohol, place the piece in strong 

 Frey's carmine for a week or longer. With free 

 hand cut a thick section from the anterior 

 cornu and the neighbouring part of the anterior 

 column and tease it out in a small quantity of 

 glycerine under a dissecting microscope, trying 

 to isolate one or more of the large nerve-cells 

 seen and throwing away the rest of the tissue. 

 In the more or less isolated cells observe 



