IX. a. The muscle = nerve preparation, b. Indirect 

 mechanical, thermal and chemical stimu- 

 lation of the gastrocnemius. 



a. The muscle=nerve preparation. 



/ Appliances. Frog board and pins ; operating case ; 

 glass nerve-hooks, like Fig. 11, A, made as follows: Take 

 a 10 cm. piece of glass rod, heat and draw in center to 

 about \ l / 2 mm. diameter; cool, cut in two, heat the 

 points to smooth them and bend the end over to form 

 the hook. 



FIG. 11. 



FIG. 11. A. Glass nerve-hook; for description see IX=a=/. B. Gastro- 

 cnemius muscle-nerve preparation. For description, see text IX=a=j>. 



Simple myograph or muscle lever (See Fig. 13). 

 Watch glass with salt crystals. 20 cm. of thick coppei 

 wire. 



2. Preparation. Pith a frog and fix to frog board, with 

 dorsum up. 



It will be taken for granted that the student is familiar 

 with the anatomy of the frog's leg and thigh. The ac- 



56 



