difference in the grades and degrees of memory of the things heard. As Kay says: “Great differences exist among individuals with regard to the acuteness of this sense (hearing) and some possess it in greater perfection in certain directions than in others. One whose hearing is good for sound in general may yet have but little ear for musical tones; and, on the other hand, one with a good ear for music may yet be deficient as regards hearing in general.” The secret of this is to be found in the degree of interest and attention bestowed upon the particular thing giving forth the sound.
It is a fact that the mind will hear the faintest sounds from things in which is centered interest and attention, while at the same time ignoring things in which there is no interest and to which the attention is not turned. A sleeping mother will awaken at the slightest whimper from her babe, while the rumbling of a heavy wagon on the street, or even the discharge of a gun in the neighborhood may not be noticed by her. An engineer will detect the slightest difference in the whir or hum of his engine, while failing to notice a
