From this source a large share of the enjoyment which men find in the active pursuits of life has its origin.
The teacher has the whole field which this subject opens fully before him.

He has human nature to deal with most directly.

His whole work is one of experimenting upon mind; and the mind which is before him to be the subject of his operation is exactly in the state to be most easily and pleasantly operated upon.

The reason now why some teachers find their work delightful, and some find it wearisomeness and tedium itself, is that some do and some do not take this view of the nature of it.

One instructor is like the engine-boy, turning, without cessation or change, his everlasting stop-cock, in the same ceaseless, mechanical, and monotonous routine.