IV. THE BAFFLING PROBLEM 71 V. SCIENTIFIC VITALISM 104 VI. A BIRD OF PASSAGE 115 VII. LIFE AND MIND 131 VIII. LIFE AND SCIENCE 159 IX. THE JOURNEYING ATOMS 188 X. THE VITAL ORDER 212 XI. THE ARRIVAL OF THE FIT 244 XII. THE NATURALIST'S VIEW OF LIFE 254 INDEX 291 The reproduction of the bust of Mr. Burroughs which appears as the frontispiece to this volume is used by courtesy of the sculptor, C. S. Pietro. I THE BREATH OF LIFE I When for the third or fourth time during the spring or summer I take my hoe and go out and cut off the heads of the lusty burdocks that send out their broad leaves along the edge of my garden or lawn, I often ask myself, "What is this thing that is so hard to scotch here in the grass?" I decapitate it time after time and yet it forthwith gets itself another head. We call it burdock, but what is burdock, and why does it not change into yellow dock, or into a cabbage? What is it that is so constant and so irrepressible, and before the summer is ended will be lying in wait here with its ten thousand little hooks to attach itself to every skirt or bushy tail or furry or woolly coat that comes along, in order to get free transportation to other lawns and gardens, to green fields and pastures new? It is some living thing; but what is a living thing, and how does it differ from a mechanical and non-living thing? If I smash or overturn the sundial with my hoe, or break the hoe itself, these things stay smashed and broken, but the burdock mends itself, renews itself, and, if I am not on my guard, will surreptitiously mature some of the burs before the season is passed. Evidently a living thing is radically different from a mechanical thing; yet modern physical science tells me that the burdock is only another kind of machine, and manifests nothing but the activity of the mechanical and chemical principles that we see in operation all about us in dead matter; and that a little different mechanical arrangement of its ultimate atoms would turn it into a yellow dock or into a cabbage, into an oak or into a pine, into an ox or into a man.