FLEXOR REFLEXES 



109 



revolution meets it and opens the key. The key itself is set on a movable 

 joint so that its lever can be horizontal or slightly tilted upward and the 

 horizontal rod on the drum-spindle opens the key only when the lever of the 

 key is horizontal. It is horizontal when it is set against a stop on the joint 

 which carries it. Adjust this bridge-key on its vertical standard so that it is 



Text-fig. 37. Scheme of arrangement of recording-apparatus, &c., for comparison of 

 reflex contraction to single break-shock with peripheral break-shock twitch. To left is shown 

 the break-key ; it can be depressed in the direction of the arrow so as to be knocked open 

 by the revolution of the horizontal striker clamped to the spindle of the recording-drum. 

 The drum is driven from the horizontal step-pulley. The spring resistance for the muscle- 

 lever is shown as furnished by a strip of rubber tubing, but a short coiled steel spring is 

 better, as more durable and taking less room. 



struck open by the drum- spindle's horizontal rod when the key-lever itself is 

 horizontal and is not touched by the drum-spindle's horizontal rod when the 

 key is slightly tilted up. Arrange the secondary circuit of inductorium so 

 that its short-circuiting bridge-key is clamped to the table near the standard 

 carrying the primary circuit-key. 



The recording-lever is of the bell-crank pattern with after-load support. 

 The resistance is provided by a thin piece of rubber tubing attached by strong 

 thread close to the axis of the lever. The resistance can be varied by varying 

 the stretch of the rubber by an adjustable clamp fixing the lower end of the 

 rubber strip. / 



