Just as it is true that it is the mind and not the eye that really _sees_; so is it true that it is the mind and not the ear that really _hears_. Many sounds reach the ear that are not registered by the mind. We pass along a crowded street, the waves of many sounds reaching the nerves of the ear, and yet the mind _accepts_ the sounds of but few things, particularly when the novelty of the sounds has passed away. It is a matter of interest and attention in this case, as well as in the case of hearing. As Halleck says: "If we sit by an open window in the country on a summer day, we may have many stimuli knocking at the gate of attention: the ticking of a clock, the sound of the wind, the cackling of fowl, the quacking of ducks, the barking of dogs, the lowing of cows, the cries of children at play, the rustling of leaves, the songs of birds, the rumbling of wagons, etc. If attention is centered upon any one of these, that for the time being acquires the importance of a king upon the throne of our mental world." Many persons complain of not being able to remember sounds, or things reaching the mind through the sense of hearing, and attribute the trouble to some defect in the organs of hearing. But in so doing they overlook the real cause of the trouble, for it is a scientific fact that many of such persons are found to have hearing apparatus perfectly developed and in the best working order--their trouble arising from a lack of training of the mental faculty of hearing. In other words the trouble is in their mind instead of in the organs of hearing. To acquire the faculty of correct hearing, and correct memory of things heard, the mental faculty of hearing must be exercised, trained and developed. Given a number of people whose hearing apparatus are equally perfect, we will find that some "hear" much better than others; and some hear certain things better than they do certain other things; and that there is a great 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.