108 PHYSIOLOGY FOR THE LABORATORY. 



4. The nucleolus. 



5. The fibres leaving the cells. Is there an axon ? 



Look for branching fibres. 



b. The network of fibres. 



c. Compare with the cells of the brain. 



d. Sketch. 



C. The Structure of Different Parts of the Spinal Cord. 



Material. Microscopical slides showing cross-sections of the 

 spinal cord in the cervical, dorsal, and lumbar regions. 

 Apparatus. A magnifying glass. 



Examine the sections of the different regions of the 

 spinal cord. 



Notice : 



a. Their comparative size and shape. Is the difference 

 due to the gray or white substance ? What shows this ? 



b. The comparative number of cells in the anterior 

 cornua. What does this signify? 



c. The comparative amounts of gray and white sub- 

 stance. To what is this due? 



d. In the cervical region note the division of the pos- 

 terior columns into a median and lateral part separated by 

 connective tissue. 



e. Make sketches showing typical sections from these 

 three regions. 



D. The Spinal Nerves. 



Materials. A frog. Chloroform. Formalin, 5 per cent. Cotton 

 batting. 



Apparatus. Glass jar. Bell-jar. 



