The idea of vegetation is irresistible in considering mental activity. Man seems a higher plant. What happens here in mankind is matched by what happens out there in the history of grass and wheat. This curious resemblance repeats, in the mental function, the germination, growth, state of melioration, crossings, blight, parasites, and in short all the accidents of the plant. Under every leaf is the bud of a new leaf, and not less under every thought is a newer thought. The plant absorbs much nourishment from the ground in order to repair its own waste by exhalation, and keep itself good. Increase its food and it becomes fertile. The mind is first only receptive. Surcharge it with thoughts in which it delights and it becomes active. The moment a man begins not to be convinced, that moment he begins to convince. In the orchard many trees send out a moderate shoot in the first summer heat, and stop. They look all summer as if they would presently burst into bud again, but they do not. The fine tree continues to grow. The same thing happens in the man. Every man has material enough in his experience to exhaust the sagacity of Newton in working it out. We have more than we use. I never hear a good speech at caucus or at cattle-show but it helps me, not so much by adding to my knowledge as by apprising me of admirable uses to which what I know can be turned. The commonest remark, if the man could only extend it a little, would make him a genius; but the thought is prematurely checked, and grows no more. All great masters are chiefly distinguished by the power of adding a second, a third, and perhaps a fourth step in a continuous line. Many a man had taken their first step. With every additional step you enhance immensely the value of your first. The botanist discovered long ago that Nature loves mixtures, and that nothing grows well on the crab-stock, but the blood of two trees being mixed a new and excellent fruit is produced. And not less in human history aboriginal races are incapable of improvement; the dull, melancholy Pelasgi arrive at no civility until the Phœnicians and Ionians come in. The Briton, the Pict, is nothing until the Roman, the Saxon, the Norman, arrives. It is observed that our mental processes go forward even when they seem suspended. Scholars say that if they return to the study of a new language after some intermission, the intelligence of it is more and not less. A subject of thought to which we return from month to month, from year to year, has always some ripeness of which we can give no account. We say the book grew in the author’s mind.