He nevertheless cites a most important fact respecting the alternations of timber growth, noticed by Sir Alexander Mackenzie, in his overland journey from Montreal to the Arctic Ocean, in 1789, who found, in the vicinity of Slave Lake, that the banks were covered with large quantities of burnt wood lying on the ground, where young poplar trees had sprung up immediately after the destruction of the previous growths by fire. In noticing this fact, the indefatigable English explorer remarks: "It is a very curious and extraordinary circumstance that land covered with spruce, pine, and white birch, when laid waste by fire, should subsequently produce nothing but poplars, _where none of that species of tree was previously to be found"_. But facts of a similar character are too numerous and well-authenticated to be questioned by any intelligent authority. And they all point to but one solution--that of primordial germs quickened into life by the necessary environing conditions. The appearance of a single poplar in the locality named, or even a dozen of them for that matter, might be accounted for on the theory that a bird of passage had dropped them there after the fire; but, under no conceivable circumstances, could the dispersion of the requisite amount of seed to plant an extensive burnt district, along the banks of Slave Lake, have occurred on any other theory than that emphatically set forth, as a physiological fact, in the Bible genesis. There is manifestly importance enough attaching to this subject to justify a much wider range of observation and inquiry than has yet been made. Pine forests have been cut off in Alabama and Georgia, covering extensive areas, where there was not a single oak tree in a circuit of miles; and yet the oak has promptly made its appearance, in several varieties, over the whole cleared district. And it is entirely safe to say that, had the ground been thoroughly examined, from the surface to ten feet below it, after the pine had been felled, not the first sign of an acorn could have been met with anywhere within the whole area of the clearing, no matter whether it covered ten acres, twenty, or a hundred. The paths of the tornadoes we have referred to conclusively show this. The new-born forests, in these cases, do not come from seed, but from the living, indestructible, vital principles implanted in the earth, before it was specifically commanded to "bring forth," in the language of the Bible genesis. The "materialists," like Professor Bastian, Herbert Spencer, and others, may sneer at this declaration, but let them advance some rational theory to the contrary, to account for these alternations of forest growths, before they lay bare the joints of their scientific armor too confidently to the thrusts of the next new-comer in the field of scientific investigation. Sneers are cheap weapons--the mere side-arms of pretension and frippery--but they never bear so deadly a gibe as when effectually turned on the sneerer.