The power of commanding the attention and concentrating the mental energy upon a given object, is, however, a power not easily acquired nor always possessed. The difficulty of the attainment is hardly less than its importance. It can be made only by earnest effort, resolute purpose, diligent culture and training. There must be strength of will to take command of the mental faculties, and make them subservient to its purpose. There must be determination to succeed, and a wise discipline and exercise of the mind with reference to the end in view. This faculty, like every other, requires education in order to its due development. _Whether certain Acts are performed without any Degree of Attention._--It is a question somewhat discussed among philosophers, whether those acts which from habit we have learned to perform with great facility, and, as we say, almost without thinking, are strictly voluntary; whether they do or do not involve an exercise of attention. Every one is aware of the facility acquired by practice in many manual and mechanical operations, as well as in those more properly intellectual. A musician sits at his instrument, scarcely conscious of what he is doing, his attention absorbed, it may be, with some engrossing topic of thought or conversation, while his fingers wander _ad libitum_ among the keys and strike the notes of some familiar tune. Is there in such a case a special act of volition and attention preceding each movement of the fingers as they glide over the keys? And in more rapid playing, even when the attention is in general directed to the act performed, _i. e._, the execution of the piece, is there still a special act of attention to the production of each note as they follow each other with almost inconceivable rapidity? Dr. Stahl, Dr. Reid and others, especially many able physiologists, have answered this question in the negative, pronouncing the acts in question to be merely automatic and mechanical, and not properly involving any activity of mind. The mind, they would say, forms the general purpose to execute the given piece, but the particular movements and muscular contractions requisite to produce the individual notes, are, for the most part, involuntary, the result of habit, not of special attention or volition.