The transient electric responses of the cochlea.

1. DC responses were recorded from the cochleae of pigeons, cats and guinea-pigs. In addition to the known summating potential, transients of the same polarity were observed at the onset and termination of the tonal stimulus.2. These transients were most noticeable in the pigeon, being least in the guinea-pig responses.3. They could be modified by changing the rate of rise and fall of the stimulus envelope, but not by cutting the middle ear muscles.4. Comparable effects were seen when the ear was directly driven by a mechanical stimulus.5. With stimuli of long duration the off-transient was usually masked by a slow potential of opposite polarity. This deflexion appears to be an afterpotential, rather than a mechanical transient, since it is dependent on the duration of the preceding stimulus.