When M. Paul dictated the trait on which the essay was to turn, I heard it for the first time; the matter was new to me, and I had no material for its treatment. But I got books, read up the facts, laboriously constructed a skeleton out of the dry bones of the real, and then clothed them, and tried to breathe into them life, and in this last aim I had pleasure. With me it was a difficult and anxious time till my facts were found, selected, and properly jointed; nor could I rest from research and effort till I was satisfied of correct anatomy;
