GENERAL PHYSIOLOGY OF MUSCLE AND NERVE TISSUE 51 



muscle is the actual weight hung upon the weight link. When the 

 lever passes a little below the horizontal position it comes in contact 

 with the rest. This rest can be used in "after-loading" a muscle. 

 For further description of the instrument see Fig. 31 and its legend. 



FIG. 30 



The Neef hammer. 



In the use of the frog-board myograph one proceeds as follows: 

 The frog is pithed and pinned, dorsum up, on the cork plate, with 

 the feet at the lever end. The tendo Achillis is exposed and loosened 

 from the tarsal ligaments; the tendon hook N is passed through 

 the tendon and the length of the thread ad justed! 'at C. The skin 

 on the thigh is opened to the extent of 2 cm. and the biceps femoris 

 muscle removed, the sciatic nerve carefully separated from the 



FIG. 31 



Frog-board myograph : S, the shaft which is clamped to the upright stand ; B, the oaken 

 base; C Pt, the cork plate to which the frog is fixed; A, the lever axis and slide lever holder; 

 W, the weight ; L, the light lever, about 20 cm. in length ; N, the tendon hook which is joined 

 through the thread T, which passed through the eye and under spring the catch C; R, the lever 

 rest. 



sciatic artery and placed on the insulated electrodes. Stimulation 

 may be made from time to time for a period of several hours before 

 the preparation becomes exhausted. 



(6) The Inductorium. This instrument consists of two spools of 

 wire: a primary circuit of few turns of coarse wire and a secondary 



