their bodies; there are the Yakutes—the "iron men," as they are called—who, in their rigorous climate, sleep in the open air and wake covered with hoar-frost; there are the Hindus, constitutionally adjusted to the tropics in such way that they can sleep in the burning sunshine; and, again, there are Indian hill-tribes living comfortably in malarious localities which are fatal not only to Europeans but to Hindus. Moreover, while we thus get proof that organisms fit themselves to their environments, we also get proof that there simultaneously result divergences and re-divergences of races and varieties. Men have spread from some original locality into other localities in all directions; and there have resulted sundry widely unlike families appropriate to their respective habitats, and less unlike breeds diverging within them, such as the Aryan peoples of Europe. This process which the human species shows us is, and always has been, the process with every kind of organism. While we are shown a general cause which has been superposing modifications upon modifications from the beginning, we are also shown how there has arisen a concomitant formation of class within class. The cause we find in operation is a cause of the kind needed to explain the remarkable relations above described.
Thus we have four great groups of observed facts (or five if we include those concerning rudimentary organs) all suggesting the same history, all converging to the same conclusion: their joint significance being immense in comparison with the significance of each group taken by itself. And in the adaptation of organisms to their conditions, directly or indirectly brought about, we have a cause which makes these aggregates of phenomena intelligible. On these mutually-verifying sets of evidences the hypothesis of evolution stands by itself, quite apart from any conclusions respecting its special causes. Hence the meaning of the assertion made above, that even were all theories about the special causes disproved, the doctrine of evolution would remain standing.
And now, having contemplated the observed facts which indirectly support the hypothesis of evolution, let us ask for the observed facts which indirectly support the alternative hypothesis. There are none. Neither in the air, nor on the earth, nor in the water do we find anything implying special creation. Nay, indeed, not only do we see no facts favoring the supposition, but we see a world of facts conflicting with it. From hour to hour incidents showing the uniformity of law and the constant relations of causes and effects generate in us convictions so incongruous with it as to produce instant disbelief of an alleged special creation now occurring. Should any one say that having taken into his room a bowl containing nothing but clear water, he saw a fish
