Page:Popular Science Monthly Volume 3.djvu/373

Rh stages of development in which there are certain likenesses, never very close, to certain forms of animal life lower down than itself in the scale of being—likenesses which simply bear witness to the unity of plan in all forms of animal life.

I also find it difficult to twist the marvellous improvability of man into an argument for the doctrine of evolution. Who shall say that this improvability is not restricted within certain prescribed limits? As yet man, in his struggle for life, has never turned his opportunities for natural selection so far to account as to make even the slightest advance toward physical improvement. And it is possible that the change for the better which is actually witnessed in man may have to be explained in accordance with the Scriptures rather than in accordance with the doctrine of evolution.

Nor can I rest satisfied with what may be spoken of as the more special evidence in favor of evolution. The pigeon, by developing under cultivation into what may be considered as improved varieties of pigeon, may at first seem to be the subject of evolution; but the changes produced in this way are never more than those minor changes which go to make up the differences called varieties, never so great as to constitute another species of bird. Moreover, only let the varieties thus produced be let alone for a few generations, and the inevitable result is a return to the original form of the common pigeon, if not to that of the wild, blue rock-pigeon. The history contradicts the notion of evolution rather than confirms it. And so with the dog or any other animal which may be modified as the pigeon is modified; the change produced is never beyond that of mere variety, never into that of a new species; and let the constraining influences which brought it about come to an end, and, as with the pigeon, it is not long before the original wild form has again cropped out. And what other conclusion can be fairly drawn from the infertility of mules than this—that there is a barrier between different species of animals, even between those which are most closely akin to each other, by which one is prevented from passing into the other. Nay, it is even difficult to find any evidence in favor of evolution in the history of the rudimentary creatures which swarm in dense crowds around the very feet of the scale of being. Here are wonderful changes at work by which, as Dr. Bastian so clearly demonstrates, bacteria, the simplest of all living units, may be developed, possibly from inorganic elements, almost at the will of the experimenter, into monads, and amœbæ, and paramecia, or into the lowest forms of fungus—into forms of animal life, that is to say, or into forms of vegetable life; but not much is to be built upon this fact in favor of evolution. For what follows? Simply this—that these forms are unstable in the highest degree, and that, instead of passing on into higher forms of being, they presently again break up into their original bacterial units, which units are destined again and again to go through