Once I saw this Great Doctor of mine a burning, vibrant force in a room of a crowded tenement, from the roof of which one could[16] not see a blade of grass or a tree. In fact, that force filled three rooms, in which lived a man and woman and five children. I spent an hour in those rooms on a Sunday afternoon, and the experience of that hour in a hot and crowded tenement was a mightier sermon than was ever preached to me in the heart of a forest. At every window was a box in which green stuff was growing. There were flowers in pots. A pair of canary-birds looked down upon the smoky roofs of a great city and sang. What interested me most was two contrivances the man had made to force oats into swift germination and growth. In a week, he told me, the green sprout of an oat would be two inches long. Then I saw why they were grown. Several times while I was there would a dove come to a window and wait for a bit of the green. I could see they were different doves. They told me at least a dozen were accustomed to come in that way. They were the children’s pets. A little baby in arms cooed at them and waved his arms in delight. I have seen many poor tenement families, but that, I think, was the only happy one. The singing of the birds, the coming of the doves, the growing of green things in their room were their inspiration, their hope,[17] the promise of dreams that would some day come true. Nature had become their religion, and yet they did not know it as such. It was calling them out into the great open spaces—and they were living in anticipation of that day when they would answer the call.

Because I have spent much of my time in adventuring in distant wildernesses, and exploring where other men have not gone, it has been accepted by many that my love for nature