LABORATORY MANUAL OF PHYSIOLOGY. 



centimetre apart. Pass a bent pin through the ring thus made, and 

 support this in the femur clamp of the myograph. Pass a fine 

 copper wire through the lower portion of the muscle ring and at- 

 tach it to the muscle lever and the binding post of the lever. Con- 

 nect this post and that of the femur clamp with a dry cell, inter- 

 posing a simple key and a signal magnet in the circuit. Adjust the 

 point of the muscle lever, the point of the signal magnet, and the 

 point of a chronograph lever, marking hundredths of a second, in 

 a straight perpendicular line against the smoked paper of a drum 

 arranged to revolve at high speed. Start the drum, place the chro- 

 nograph in circuit with the vibrating tuning-fork, open and close 

 the key in the battery circuit. 



Compare the length of the latent period and the form of the con- 

 traction curve with that of skeletal muscle. 



2. Make a second similar preparation, omitting the electrical 

 apparatus for stimulation, and allow the lever of the myograph to 

 rest against a drum revolving once an hour. 



Observe tonic- contractions of the muscle. 



i 4 6] 



