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Page:Popular Science Monthly Volume 1.djvu/329

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MR. MARTINEAU ON EVOLUTION.
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are as actively locomotive as the minute creatures classed as animals seen along with them; and among these lowest types of living things it is common for the life to be now predominantly animal and presently to become predominantly vegetal. The very name zoospores, given to germs of algæ, which for a while swim about actively by means of cilia, and presently settling down grow into plant-forms, is given because of this conspicuous community of nature. So complete is this community of nature that for some time past many naturalists have wished to establish for these lowest types a sub-kingdom intermediate between the animal and the vegetal: the reason against this course being, however, that the difficulty crops up afresh at any assumed places where this intermediate sub-kingdom may be supposed to join the other two. Thus the assumption on which Mr. Martineau proceeds is diametrically opposed to the conviction of naturalists in general.

Though I do not perceive that it is specifically stated, there appears to be tacitly implied a fourth difficulty of an allied kind—the difficulty that there is no possibility of transition from life of the simplest kind to mind. Mr. Martineau says, indeed, that there can be "with only vital resources, as in the vegetal world, no beginning of mind;" apparently leaving it to be inferred that in the animal world the resources are such as to make the "beginning of mind" comprehensible. Whether any consciousness of an incongruity between the conception of "germs of mind as well as the inferior elements," and his hypothesis of universal mind as the cause of evolution, prevented Mr. Martineau from pressing this objection, I do not know. But, had he asserted a chasm between mind and bodily life, for which there is certainly quite as much reason as for asserting a chasm between animal life and vegetal life, the difficulties in his way would have been no less insuperable. For those lowest forms of irritability in the animal kingdom, which, I suppose, Mr. Martineau refers to as the "beginning of mind," are not distinguishable from the irritability which plants display: they in no greater degree imply consciousness. If the sudden folding of a sensitive-plant's leaf when touched, or the spreading out of the stamens in a cistus-flower when you brush them, is to be considered as a vital action of a purely physical kind, then so too must be considered the equally slow retraction of a polype's tentacles. And yet, from this simple motion of an animal having no nervous system, we may pass by insensible stages through ever-complicating forms of actions, with their accompanying signs of feeling and intelligence, until we reach the highest. Even apart from the evidence derived from the ascending grades of animals up from zoophytes, as they are significantly named, it needs only to observe the evolution of a single animal to see how baseless is the assumption that there exists any break or chasm between the life that shows no mind and the life that shows mind. The yolk of an egg which the cook has just broken not only yields no sign of mind, but yields no sign of life. It does not re-