APPENDIX 



187 



the desired parts. After either operation, give the frog 

 several hours to recover. About three frogs should be oper- 

 ated upon, and one chosen that best illustrates the points 

 involved. The important point is to have the medulla and 

 cerebellum left. 



m 



Fig. 78. — Diagram of the central nervous system of the frog, showing levels 

 at which cuts are made in the experiments on the functions of the sensory- 



neuro-muscular system. 



Frog C. Entire brain removed. Frog B may be used. Cut 



medulla at 6, just back of the skull, pith forward and about 



5 mm. backward. 

 Frog D. Brain and cord removed. Cut at h and destroy cord 



by pithing. 

 Procedure for demonstration: 



The following are points that may be noted about the different 



frogs. Others might be added, but it seems better to call 



