The best authorities agree in the idea that the Perception may be best cultivated by acquiring the habit of examining things in detail. And, that this examination in detail is best manifested by examining the parts going to make up a complex thing, separately, rather than examining the thing as a whole. Halleck says regarding this point: "To look at things intelligently is the most difficult of all arts. The first rule for the cultivation of accurate perception is: Do not try to perceive the whole of a complex object at once. Take the human face for example. A man holding an important position to which he had been elected offended many people because he could not remember faces, and hence failed to recognize individuals the second time he met them. His trouble was in looking at the countenance as a whole. When he changed his method of observation, and noticed carefully the nose, mouth, eyes, chin and color of hair, he at once began to find recognition easier. He was no longer in danger of mistaking A for B, since he remembered that the shape of B's nose was different, or the color of his hair at least three shades lighter. This example shows that another rule can be formulated: Pay careful attention to details.... To see an object merely as an undiscriminated mass of something in a certain place is to do no more than a donkey accomplishes as he trots along." Brooks says regarding the same point: "To train the powers of observation we should practice observing minutely. We should analyze the objects which we look at into their parts, and notice these parts. Objects present themselves to us as wholes; our definite knowledge of them is gained by analysis, by separating them into the elements which compose them. We should therefore give attention to the details of whatever we are considering; and thus cultivate the habit of observing with minuteness.... It is related of a teacher that if, when hearing a class, some one rapped at the door, he would look up as the visitor entered and from a single glance could tell his appearance and dress, the kind of hat he wore, kind of necktie, collar, vest, coat, shoes, etc. The skillful banker, also, in counting money with wondrous rapidity, will detect and throw from his pile of bills the counterfeits which, to the ordinary eye, seem to be without spot or blemish."