Epicurus, in the beginning of his letter to Meniceus,--[Diogenes Laertius, x. 122.]--says, “That neither the youngest should refuse to philosophise, nor the oldest grow weary of it.” Who does otherwise, seems tacitly to imply, that either the time of living happily is not yet come, or that it is already past. And yet, a for all that, I would not have this pupil of ours imprisoned and made a slave to his book; nor would I have him given up to the morosity and melancholic humour of a sour ill-natured pedant.