But generalizations, again, though in themselves the work of a happier moment, of some genetic flash in the brain of man, gone before one can say it lightens, are the result of ideas slowly gathered and long steeped and clarified in the mind, each in itself a composite of the carefully observed relations of separate and seemingly disparate facts. What is the pedigree of almost all great fortunes? Through vast combinations of trade, forlorn hopes of speculation, you trace them up to a clear head and a self-earned sixpence. It is the same with all large mental accumulations: they begin with a steady brain and the first solid result of thought, however small--the nucleus of speculation. The true aim of the scholar is not to crowd his memory, but to classify and sort it, till what was a heap of chaotic curiosities becomes a museum of science. It may well be questioned whether the invention of printing, while it democratized information, has not also levelled the ancient aristocracy of thought. By putting a library within the power of every one, it has taught men to depend on their shelves rather than on their brains; it has supplanted a strenuous habit of thinking with a loose indolence of reading which relaxes the muscular fiber of the mind. When men had few books, they mastered those few; but now the multitude of books lord it over the man. The costliness of books was a great refiner of literature. Men disposed of single volumes by will with as many provisions and precautions as if they had been great landed estates. A mitre would hardly have overjoyed Petrarch as much as did the finding of a copy of Virgil. The problem for the scholar was formerly how to acquire books; for us it is how to get rid of them. Instead of gathering, we must sift. When Confucius made his collection of Chinese poems, he saved but three hundred and ten out of more than three thousand, and it has consequently survived until our day. In certain respects the years do our weeding for us. In our youth we admire the verses which answer our mood; as we grow older we like those better which speak to our experience; at last we come to look only upon that as poetry which appeals to that original nature in us which is deeper than all moods and wiser than all experience. Before a man is forty he has broken many idols, and the milestones of his intellectual progress are the gravestones of dead and buried enthusiasms of his dethroned gods.