The behaviour of the sensory- and the ganglia cells in response to inadequate stimuli was studied at 12 adult guinea pigs. The sensory cells of the three Cristae ampullares dont respond remarkably to acoustic stimulation. At the range of 1000 Hz a recognizable increase in the size of the sensory cells at the upper ampulle was noticed. Of no account was the rest of the volume variations. At the range of 5000 Hz the sensory cells of the Maculae staticae responded with a considerable increase in the size of their sensory nuclei up to 38%. The cells of the Ganglion vestibulare react upon acoustic stimulation throughout with an increase in their nuclei up to between 16% and 54%. It was noticed that the volume enlargement increases from the lower to the higher frequencys. The cells of the Ganglion geniculi nervi facialis react upon acoustic impulses too with an increase in their nuclear volume. In low tone acoustic range and in high tone acoustic range the growth rates are more than 50% beyond the standard. Thos cells respond to frequency of 1000 Hz remarkably intensive. It was noticed that the maximum volume increase of their nuclei was in the average up to 103%. All the sensory and ganglia cells react upon rinsing the external auditory canal with 12 degrees C water, with a shrinkage of their nuclei. Besides that the sensory cells of the Cristae and the Maculae show a volume decrease between 8% and 19%. The cells of the Ganglion vestibulare et geniculi respond with a considerable volume decrease of their nuclei from 32 to 41% under the average.