And it is worth noting that they all seem to be utterly unconscious of wrong-doing.  Their repugnance to novel hypotheses is only the natural and healthy one.  A change of a wonted line of thought is not made without an effort, nor need be made without adequate occasion.  Some courage was required of the man who first swallowed an oyster from its shell; and of most of us the snail would still demand more.  As the unaccustomed food proves to be good and satisfying, and also harmless, we may come to like it.  That, however, which many good and eminent naturalists find to be healthful and reasonable, and others innocuous, a few still regard as most unreasonable and harmful.  At present, we call to mind only two who not only hold to the entire fixity of species as an axiom or a confirmed principle, but also as a dogma, and who maintain, either expressly or implicitly, that the logical antithesis to the creation of species as they are, is not by law (which implies intention), but by chance.  A recent book by one of these naturalists, or rather, by a geologist of eminence, the “Story of the Earth and Man,” by Dr. Dawson,4 is now before us.  The title is too near that of Guyot’s “Earth and Man,” with the publication of which popular volume that distinguished physical naturalist commenced his career in this country; and such catch-titles are a sort of trade-mark.  As to the nature and merits of Dr. Dawson’s work, we have left ourselves space only to say:  1.  That it is addressed ad populum, which renders it rather the more than less amenable to the criticisms we may be disposed to make upon it. 2.  That the author is thoroughly convinced that no species or form deserving the name was ever derived from another, or originated from natural causes; and he maintains this doctrine with earnestness, much variety of argument and illustration, and no small ability; so that he may be taken as a representative of the view exactly opposed to that which is favored by those naturalists whose essays we have been considering—­to whom, indeed, he stands in marked contrast in spirit and method, being greatly disposed to argue the question from the remote rather than the near end. 3.  And finally, he has a conviction that the evolutionary doctrines of the day are not only untrue, but thoroughly bad and irreligious.  This belief, and the natural anxiety with which he contemplates their prevalence, may excuse a certain vehemence and looseness of statement which were better avoided, as where the geologists of the day are said to be “broken up into bands of specialists, little better than scientific banditti, liable to be beaten in detail, and prone to commit outrages on common-sense and good taste which bring their otherwise good cause into disrepute;” and where he despairingly suggests that the prevalence of the doctrines he deprecates “seems to indicate that the accumulated facts of our age have gone altogether beyond its capacity for generalization, and, but for the vigor which one sees everywhere, might be taken as an indication that the human mind has fallen into a state of senility.”