A complete explanation of these early vague alarms of the ear may as yet not be possible. Children show in the matter of sound capricious repugnances which it is exceedingly difficult to account for. They seem sometimes to have their pet aversions like older folk. Yet I think that a general explanation is possible. To begin with, then, it is probable that in many of these cases, especially those occurring in the first six months, we have to do with an organic phenomenon, with a sort of jar to the nervous system. To understand this we have to remember that the ear, in the case of man at least, is the sense-organ through which the nervous system is most powerfully and profoundly acted on. Sounds seem to go through us, to pierce us, to shake us, to pound and crush us. A child of four or six months has a nervous organisation still weak and unstable, and we should naturally expect loud sounds to produce a disturbing effect on it. To this it is to be added that sounds have a way of taking us by surprise, of seeming to start out of nothing; and this aspect of them, as I have pointed out above, may well excite vague alarm in the small creatures to whom all that is new and unlooked for is apt to seem uncanny. The fact that most children soon lose their fear by getting used to the sounds seems to show how much the new and the mysterious has to do with the effect. Whether heredity plays any part here, _e.g._, in the fear of the dog’s barking and other sounds of animals, seems to me exceedingly doubtful. This point will, however, come up for closer consideration presently, when we deal with children’s fear of animals.