an amphitheatre, and utter the stereotyped "In our last lecture we ended with . . ." and the sentences fly out of my soul in a long line—then it is full steam ahead. I speak with irresistible speed, and with passion, and it seems as though no earthly power could check the current of my speech. In order to lecture well, that is without being wearisome and to the listener's profit, besides talent you must have the knack of it and experience; you must have a clear idea both of your own powers, of the people to whom you are lecturing, and of the subject of your remarks. Moreover, you must be quick in the uptake, keep a sharp eye open, and never for a moment lose your field of vision.
When he presents the composer's thought, a good conductor does twenty things at once. He reads the score, waves his baton, watches the singer, makes a gesture now towards the drum, now to the double-bass, and so on. It is the same with me when lecturing. I have some hundred and fifty faces before me, quite unlike each other, and three hundred eyes staring me straight in the face. My purpose is to conquer this many-headed hydra. If I have a clear idea how far they are attending and how much they are comprehending every minute while I am lecturing, then the hydra is in my power. My other opponent is within me. This is the endless variety of forms, phenomena and laws, and the vast number of ideas, whether my own
