Two things have helped on this confusion. One is the notion of the direct and independent creation of species, with only an ideal connection between them, to question which was thought to question the principle of design. The other is a wrong idea of the nature and province of natural selection. In former papers we have over and over explained the Darwinian doctrine in this respect. It may be briefly illustrated thus: Natural selection is not the wind which propels the vessel, but the rudder which, by friction, now on this side and now on that, shapes the course. The rudder acts while the vessel is in motion, effects nothing when it is at rest. Variation answers to the wind: "Thou hearest the sound thereof, but canst not tell when it cometh and whither it goeth." Its course is controlled by natural selection, the action of which, at any given moment, is seemingly small or insensible; but the ultimate results are great. This proceeds mainly through outward influences. But we are more and more convinced that variation, and therefore the ground of adaptation, is not a product of, but a response to, the action of the environment. Variations, in other words, the differences between individual plants and animals, however originated, are evidently not from without but from within--not physical but physiological. We cannot here assign particularly the reasons for this opinion. But we notice that the way in which varieties make their appearance strongly suggests it. The variations of plants which spring up in a seed-bed, for instance, seem to be in no assignable relation to the external conditions. They arise, as we say, spontaneously, and either with decided characters from the first, or with obvious tendencies in one or few directions. The occult power, whatever it be, does not seem in any given case to act vaguely, producing all sorts of variations from a common centre, to be reduced by the struggle for life to fewness and the appearance of order; there are, rather, orderly indications from the first. The variations of which we speak, as originating in no obvious casual relation to the external conditions, do not include dwarfed or starved, and gigantesque or luxuriant forms, and those drawn up or expanded on the one hand, or contracted and hardened on the other, by the direct difference in the supply of food and moisture, light and heat. Here the action of the environment is both obvious and direct. But such cases do not account for much in evolution.