THE CHANGE IN FORM 333 



and the time relations of the shortening, but not 

 the thickening of the muscle. (See page 339.) 



The Muscle Curve. Prepare a gastrocnemius 

 muscle together with the distal third of the 

 femur. Fasten the latter in the muscle clamp. 

 Attach the tendo Achillis to the hook on the 

 muscle lever by means of a fine copper wire 

 which should be wrapped round the hook and 

 the end then carried to the binding post on the 

 muscle lever. Place a ten-gram weight in the 

 scale-pan. Connect the posts on the clamp and 

 the lever with the secondary coil of an inducto- 

 riurn arranged for maximal induction currents. 

 In the primary circuit place an electromagnetic 

 signal. Bring the writing points of the signal 

 and the muscle lever against the smoked paper 

 in the same vertical line. Start the drum at its 

 most rapid speed. Stimulate the muscle with a 

 maximal break .current. 



The muscle will shorten and then extend, 

 marking a period of rising energy and a period 

 of sinking energy. Note that the period of rising 

 energy is shorter than the period of sinking 

 energy. Close observation will show that the 

 lever does not begin to move at the instant the 

 muscle is stimulated, there is here an interval 

 or latent period. 



The Duration of the Several Periods. Turn to 



