Chronic spinal frogs were found to develop hyperexcitability, manifested by greatly increased resistance to habituation of the flexion reflex, consequent to spinal cord transection. Also investigated were the following aspects of centrally mediated response depression produced by repeated stimulation: ( a) the cumulative response depression of three days of habituation training had dissipated in five of seven animals within six days; ( b) dishabituation in the spinal frog, as in the acute spinal cat, is mediated by a superimposed facilitation rather than a reversal of the habituation process; ( c) approximately equal response depressions were produced by 60 stimuli delivered 1 30 sec, 1 10 min, or in 20 trains of three stimuli 15 sec apart delivered 1 30 min.