1906.] On Innervation of Antagonistic Muscles. 481 



30 per cent. The after-increase of the reflex may persist in evidence for 

 many seconds. Its decline is gradual. 



Fig. 2. — "Mark -time" reflex as before; but the reflex is here interrupted by stimulation of the tail. This 

 arrest, due to inhibition, is followed, after cessation of the inhibitory stimulus, by increase in amplitude and 

 slightly in frequence of the reflex. The signal registers period of application of inhibitor}' stimulus. Time 

 registered in seconds. 



The arrest of the stepping reflex by tail inhibition cannot be prolonged 

 indefinitely. The reflex tends to return in spite of the inhibitory stimulation 

 when the latter is long persisted in. It is different when the stepping reflex 

 is arrested by lifting one knee ; the reflex does not then tend to break 

 through the arrest, however long the latter be continued. In this form of 

 arrest of the reflex the arrest seems referable simply to cessation of the 

 stimulus which excites the reflex. In the case of arrest by tail inhibition 

 the arrest seems referable to a central inhibition, the peripheral stimulus, E, 



