A method is described in the report of Wever and Bray1 that is accurate and reliable and makes it possible for the first time to study the effect of experimental lesions of the sound transmitting apparatus in animals. Cats were used by us because of the simplicity of the required cerebellar approach and the ease with which the middle ear may be exposed without injury to the tympanic membrane or ossicles. The experimental procedure consists of placing an electrode on or near the auditory nerve and grounding the other electrode in the muscles of the neck. Wires connected to these electrodes lead to a six-tube amplifier in another part of the building. Spoken words and pure tones from various instruments are transmitted by the animal's middle ear to the nerve, causing either a change in potential or modifying in some way the circuit leading to the amplifier.2 If