When, for instance, we read a printed book, the eye glances so rapidly from sentence to sentence, that we can hardly persuade ourselves that we actually see successively every letter. We certainly have no recollection of having gone through such an innumerable train of conscious acts as the theory necessarily implies. That such, however, is the case, is proved by the fact, that if by accident any letter is omitted, or transposed, or put upside down, the eye at once detects the mistake. The fact is familiar to all. It can be accounted for only on the supposition that, even in the rapid and cursory perusal of a book, the eye actually passes from letter to letter, and gives to each a distinct notice. It not only notices each letter, but the position of each in reference to the other letters in the line, and even those nice diacritical points by which one letter is distinguished from another, as _c_ from _e_, _u_ from _n_, _b_ from _d_, _p_ from _q_. This notice, however, is so slight, the transition is so rapid, that we have no recollection of it afterwards, and we can hardly persuade ourselves that such has been the sober and yet most wonderful fact. Take another instance. If, on the occasion of an evening assemblage, by a sudden movement of the gas-pipe, any one should instantly extinguish all the lights in the room and leave the building for a time in total darkness, and if, by an equally sudden movement, he should then restore the light to its previous condition, every one present would notice the change and have a distinct recollection of it afterwards. Yet, every time we close our eyes in winking, that is, several times in every minute of our waking hours, we experience precisely this change from full and perfect vision to total darkness. But no one ever notices or remembers the fact of his winking, unless he stops to make it the subject of special attention. Sight however is not the only means of illustrating this point. We are drawn to a similar conclusion by observing the workings of the mind itself, in the act of volition. Whenever we make any single volition an object of special attention, we are conscious of that volition, and we have a distinct recollection of it afterwards. Yet probably not one out of ten thousand, possibly not one out of a million, of our simple volitions, is ever known to us after the moment of its occurrence. In voluntary muscular action, every distinct movement requires a distinct volition. And how innumerable are the movements necessary to the accomplishment of any one of the ordinary purposes of life! We sit down for example to write a letter to a friend. The nimble pen dances from point to point over the darkening page, and when we reach the bottom, we have not the least recollection of having willed any one of those countless muscular movements which have been necessary to what, but for its every-day occurrence, would be accounted the greatest feat of legerdemain ever performed by man!