Abstract
The initial Preyer reflex was observed in the mouse 9 to 14 days after birth with a mode of 12 days. The onset of the cochlear potential was observed on the average of 11.6 days after birth. The onset of the N1 N2 was observed on the average of 12.5 days after birth. The onset of the Preyer reflex was found to be associated with both the initial cochlear potential and the N1 N2. The Ni N2 of the immature mouse had a greater latency and smaller amplitude than that of the mature mouse. There were no gross differences found in the organ of Corti in those animals with and without a Preyer reflex. There were no differences found in the organ of Corti in those animals who had or did not have the cochlear potential and an Ni N2.