When we consider how soon some plants which spread rapidly by seeds or roots would cover an area equal to the surface of the globe, how soon some species of trees, as the white willow, for instance, would equal in mass the earth itself, if all their seeds became fall-grown trees, how soon some fishes would fill the "ocean if all their ova became full-grown fishes, we are tempted to say that every organism, whether animal or vegetable, is contending for the possession of the planet, and if any one were sufficiently favored, supposing it still possible to grow as at first, it would at length convert the entire mass of the globe into its own substance. Nature opposes to this many obstacles, as climate, myriads of brute and also human foes, and of competitors which may preoccupy the ground. Each species suggests an immense and wonderful greediness and tenacity of life, as if bent on taking entire possession of the globe wherever the climate and soil will permit, and each prevails as much as it does, because of the ample preparations it has made for the contest. It has received a myriad chances, because it never depends on spontaneous generation to save it.
March 23, 1853. 5 a. m. I hear the robin sing before I rise. 6 a. m. Up the North River. A fresh, cool, spring morning. The
