the pupil must be actually in possession of principles previously expounded for which he may be called upon at any time. It is simply impossible for a person to be absent and neglectful for a time in his study, and then come into the class-room to make a brilliant show on an intermediate fragment of the subject. He can be too easily exposed as a humbug to attempt it a second time. Moreover, thus to force him to do the work as he goes along is the greatest favor one can do for the pupil; and the usual cramming before the examination becomes, in reality, a general review, which is very useful in bringing him to see the connection existing throughout the whole subject.
4. If the class is too large to reach each member as often as the instructor might wish in the above method, there is one device which is more or less useful. At the beginning of the hour let him write a question upon the blackboard, to be answered by each one in writing within the first fifteen minutes. The attempt to write out an explanation clearly, without hint or clew from the instructor, will reveal to the best student the deficiencies and gaps in his knowledge. Each one will then have the keenest interest to know what is considered a satisfactory answer to the question. At the next exercise of the class, the instructor can read some good and some bad answers, point out the general mistakes, and advise them for the future. No exercise can be better than this in cultivating the habit of careful expression, and in learning how to make a clear and pointed exposition of a subject in a brief space of time. This practice tends to secure the accuracy which in the oral discussions is made second to fluency and readiness.
5. Since the chief work of the class-room is not to enable students to discover principles, but rather to understand and apply them, probably the most useful method of interesting a class is to present to them by extracts from the newspapers of the day bits of fallacious discussions which may come under the head of the subject in hand, and ask for criticism and discussion of them. The appositeness of a timely topic is peculiarly valuable for such purposes. In fact, the practical matters of our own country will never fail to excite a lively interest in almost any class; and through this interest the teacher can find a way of leading men to study principles more carefully. A national or State campaign is very likely to furnish an instructor with a plentiful supply of extracts for discussion by his class. The learner in political economy is not hindered by the same disagreeable obstacles, as impede the medical student, in finding subjects on which to put his learning into practice.6. Many minds are unable to keep hold of an abstraction, or general principle; or they have been untrained in making nice distinctions between ideas or definitions. Just as in beginning a strange language, when words of widely different meaning have a similarity to the untutored eye, the distinctions do not make much impression. So it is in regard to ideas and definitions in political economy. There-