=A. Differences in Thought.=--One of the obvious classifications of pupils is that of "quick" and "slow." The former learns easily, but often forgets quickly; the latter learns slowly, but usually retains well. The former is keen and alert; the latter, dull and passive. The former frequently lacks perseverance; the latter is often tenacious and persistent. The former unjustly wins applause for his cleverness; the latter, equally unjustly, wins contempt for his dulness. The teacher must not be unfair to the dull plodder, who in later years may frequently outstrip his brilliant competitor in the race of life. Some pupils think better in the abstract, others, in the concrete. The former will analyse and parse well in grammar, distinguish fine shades of meaning in language, manage numbers skilfully, or work out chemical equations accurately. The latter will be more successful in doing things, for instance, measuring boards, planning and planting a garden plot, making toys, designing dolls' clothes, and cooking. The schools of the past have all emphasized the ability to think in the abstract, and to a large extent ignored the ability to think in the concrete. This is unfair to the one class of thinkers. From the ranks of those who think in the abstract have come the great statesmen, poets, and philosophers; from the ranks of those who think in the concrete have come the carpenters, builders, and inventors. It will be admitted that the world owes as great a debt from the practical standpoint to the latter class as to the former. Let the school not despise or ignore the pupil who, though unable to think well in abstract studies, is able to do things. =B. Differences in Action.=--There is a marked difference among children in the ability to connect an abstract direction with the required act. This is particularly seen in writing, art, and constructive work, subjects in which the aim is the formation of habit, and in which success depends upon following explicitly the direction given. The teacher will find it economical to give very definite instruction as to what is to be done in work in these subjects. It is equally important that instructions regarding conduct should be definite and unmistakable.