In a comparison of the ear of a new-born child with that of an adult, it is found that certain parts differ greatly in the two cases, while others are nearly identical, for the growth of the various parts of the ear is not uniform, some not being fully formed until after puberty, while others attain their adult size and form by the end of fetal life. To the latter category belong the internal ear, the tympanic cavity with its auditory ossicles and the mastoid antrum; to the former, the external auditory meatus, the eustachian tube and the mastoid portion of the temporal bone. With this in mind, my purpose in this paper is to show by a comparison of figures the actual measurements of the various parts of the bony labyrinth at different ages.
In recent years, although the physiology and histology of the internal ear in the human