114 ELEMENTARY PHYSIOLOGY. [X. 



F. Cells of Spinal Coed. 



Cut transverse sections of the spinal cord of a 

 large mammal (e. g. calf or ox) which has been 

 hardened in ammonium bichromate 2 p. c. and 

 subsequently treated with alcohol. Stain with 

 carmine or dilute picrocarmine (it is better still 

 to stain the small piece of cord before cutting 

 sections by placing it in strong Frey's carmine for 

 several days) ; clear and mount in balsam. Note 



a. In the white substance the cut ends of the 

 nerve-fibres differing very greatly in size 

 (cp. with A § 4). 



5. The small amount of connective tissue (neu- 

 roglia) between the nerve fibres; this is finely 

 dotted (transverse sections of semi-elastic 

 fibrils), and is more abundant near the grey 

 substance. 



c. In the grey substance of the anterior comu, 

 the large multipolar nerve-cells each with a 

 large nucleus and distinct nucleolus. Select a 

 conspicuous cell and note that the processes 

 run off in all directions; many of them will be 

 seen to branch and these branches to branch 

 again and so on (protoplasmic processes); 

 from some of the cells a rather large process 

 which does not branch may be seen to run 

 outwards through the white substance (axis 

 cylinder process). 



d. In the grey substance of the posterior comu, 

 the much smaller usually fusiform nerve-cells 

 with branching processes at either end. 



