MUSCLE-NERVE PHYSIOLOGY. 



511 



Fig. 325. Arrangement of the apparatus necessary for recording muscle contractions 

 with a revolving cylinder carrying smoked paper. A, Revolving cylinder ; B, the frog arranged 

 upon a cork-covered board which is capable of being raised or lowered on the upright, which 

 also can be moved along a solid triangular bar of metal attached to the base of the recording 

 apparatus the tendon of the gastrocnemius is attached to the writing lever, properly weighted, 

 by a ligature. The electrodes from the secondary coil pass to the apparatus being, for the 

 sake of convenience, first of all brought to a key, D (Du Bois ReymomTs) ; C, the induction 

 coil ; F, the battery (in this fig. a bichromate one) ; E, the key (Morse's) in the primary circuit. 



inserted behind it. The tendo-achillis k divided from its attachment to the 

 os calcis, and a ligature is tightly tied round it. This tendon is part of the 

 broad muscle of the thigh (gastrocnemius) , which arises from above the con- 



Fig. 326. Moist Chamber. 



