The practical recognition of the difference between teacher and professor would be a decided step. By the side of it those which we have already taken would appear insignificant. The addition of chemistry, geology, or physiology to the previous curriculum does not change its character, so long as the professors of those branches instruct after the fashion of the professors of Latin and Greek. The advantage that the men of natural science have over their colleagues is one which the nature of the subject brings with it. In order to teach at all, they must come in close personal contact with their pupils, and to escape falling behind in their department, where new theories succeed one another with such rapid bounds, they must continue a certain amount at least of original research. Supplementing the present curriculum by post-graduate courses will hardly suffice. Such courses are open to serious objections. If conducted by the regular professors, they impose additional burdens upon men who have already more than enough. If conducted by special professors, they will tend to raise those professors at the expense of the regular faculty. A lecturer to graduates must necessarily appear, in the eyes of the undergraduate, superior to the man who hears recitations and prepares term-reports. Besides, young men who have passed four years at one college need "a change of air:" they will develop more rapidly if brought into contact with new ideas and new instructors. Every institution has an atmosphere of its own, which ceases after a time to act upon the student as a stimulant.