"The old teacher is too likely to become didactic, dogmatic and 'bossy' if she does not constantly strive with herself. Why? She has to be thus five days in the week and, therefore, she is likely to be so seven. She knows arithmetic, grammar and geography to their uttermost and she is never allowed to forget that she knows them, and finally her interests become limited to what she knows.
After all, what is the chief sign of growing old? Is it not the feeling that we know all there is to be known? (snip)
I know how to 'make magic' for the teacher who is growing old. Let her go out with her youngest pupil and fall on her knees before the miracle of the blossoming violet and say: 'Dear Nature, I know naught of the wondrous life of these, your smallest creatures. Teach me!'"
--Anna Botsford Comstock (1854-1930) from her book Handbook of Nature Study