This applies to all movements, of whatever kind, that we at any time execute. Without the past--_i.e._, without memories--no present. Some of the memories associated with an act may be lost, and others, sufficient for its performance in some fashion, remain. A man may forget, after the lapse of months or years, how to tie his necktie in a certain way, as he stands before a mirror; yet on turning away he may succeed at once. In this case the visual memories, those that come through the eyes, were lost, but others, those associated with muscular movements, remain. The muscular sense may prove an adequate guide when the visual is ineffective. In the same way, one may call up a melody by moving the fingers over the piano keys, when it cannot otherwise be recovered, or one rescues an air from oblivion by humming a few of its tones; all of which is explained by the revival of muscular and similar memories. All voluntary movements are at first accomplished relatively slowly and with difficulty. They soon weary us. A child learns to walk with the greatest difficulty, and only after numberless failures or errors. The first tones of the would-be pianist or violinist are produced but slowly and with great difficulty, in spite of the most determined effort. If the attempts to vocalize are any more successful, it is because one has already learned to talk--a process that in the first instance (in infancy) was even more laborious than that of walking. The degree to which any one succeeds in his earliest efforts to sing a scale will depend on the readiness with which he can use a variety of neuro-muscular mechanisms--indeed, all those associated with the respiratory, laryngeal, and resonance apparatus. Fortunately for the voice-user, this apparatus has all been in use in ordinary speaking. But when this latter process is analyzed, it is found that it is not essentially different from singing. In each the same mechanism is used, and in much the same way; but every one knows that not all who can talk are able to sing, and it is usual to say that those who cannot have no "ear" for music; and this expresses a part of the truth, though not in a scientific way. What is really the truth is found to be, on analysis, that certain guiding sensations, chiefly those from the hearing apparatus (ear, nerves, brain), are insufficient, owing either to natural defect or lack of training; but that this is not the only explanation is plain from the fact that many composers with the most vivid musical imagination, the most perfect auditory memory, and the most acute ear, cannot sing in any but the most imperfect manner. As we have said before, the speaker of great power to affect his fellows through tones, or the artistic singer, must be a sort of vocal athlete. In the athlete there is a very perfect association into one whole of certain sensations from eye, skin, muscles, etc., and certain movements. These exist in all men, but in very unequal degree.