The kind way in which this series of papers has been received has been a pleasure greater than I dared to anticipate. I felt that I was a late comer in the midst of a crowd of ardent and eager candidates for public attention, that I had already had my day, and that if, like the unfortunate Frenchman we used read about, I had "come again," I ought not to surprised if I received the welcome of Monsieur Tonson.