The reflex activity in three groups of cats in which the spinal cord had been asphyxiated for 30 to 55 min, and which had been kept from one day to 2 weeks afterwards was compared with that in acute and chronic spinal control animals. Asphyxiation tended to produce in addition to a slight and transient initial tone a more pronounced secondary tone which developed usually a few hours after asphyxiation and tended to decrease or disappear from a few hours to 3 days later. A permanent late tone often developed in the legs about one week after asphyxiations of 30 to 35 min. In preparations with secondary tone the post-activation depression was less pronounced than in the controls and there was during certain phases of the recovery cycle evidence of indirect, interneuronal facilitation. Inhibition of the responses caused by stimulation of the gastrocnemius nerve by stimulation of the sural nerve was absent and antidromic inhibition was less pronounced than in the controls. The spinal cords of these preparations did conduct impulse trains at 50 to 400sec considerably better than in acute spinal control preparations. Preparations asphyxiated for 30 to 35 min and exhibiting late tone in the legs showed a moderate post-activation depression. They exihibited antidromic inhibition.