fresh investigation of the facts bearing upon the distribution, gradation, and variability of species, much presumptive proof of evolution has accumulated. What was required further, and what "natural selection" has now to some extent supplied, was not so much additional positive arguments, as the production of a theory that should not in its mode of operation do violence to the facts pointing so strongly in an opposite direction. A secondary cause, known to operate within certain limits, and which may have operated through the whole extent of organic life, and bound all species of an order into a united whole is brought to light. It is endeavored thus to put the advocates of the independent creation of species on the defence, and to throw the burden of proof upon those who deny the organic unity of the animal and vegetable creation. Of the defences put forth for the oldtime view of the manner of the production of species we will speak in the next chapter.

CHAPTER III.

OBJECTIONS TO DARWINISM AND THE REJOINDERS OF ITS ADVOCATES.

I. A Mere Theory.

THE comprehensive objection to the view that species have been transmuted into one another mainly through the agency of natural selection is, that it is a mere theory, supported by some vague analogies and by very few facts. It is alleged that nearly all the facts upon which the view is based had been before the world for a half-century or more, and that it is not likely that so simple a clue to the maze as Mr. Darwin proposes would have escaped the notice of preceding naturalists.

The objection is well taken, when urged against the sweeping generalizations of many who have espoused the doctrine. Very likely Mr. Darwin, even, with all his caution, has not escaped altogether the danger of being the servant, rather than the master, of his theory. It should, however, be remembered that Darwin was not in haste to publish, but, after he was recognized as among the most careful of scientific observers, worked assidu

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ously, but silently, over his problem for twenty years. Furthermore, the publication was hastened by the circumstance that another scientific observer (Mr. Wallace) had been led independently to a similar, or even identical, theory.

However much value this objection of novelty might have had at the beginning, the theory has now been too long under discussion, and swept too many students of nature under its influence, lightly or sneeringly to be set aside. One thing is certain; it has not proved an easy task to invalidate the theory altogether. Indeed, little has been attempted by the candid opponents of natural selection except to set metes and bounds to its operations. As to the importance of the facts adduced, they must speak for themselves. The contemporaries of Newton derided him for taking notice of the analogy between the falling of an apple and the motion of the moon. Comte, the father of what is called the "positive philosophy," spoke with contempt of those who, from the analogy between light and heat, endeavored to correlate their laws of action. It is to be remembered that there is analogy and analogy. The argument from analogy applies to almost every subject, and carries every degree of probability. It would be difficult to go into a forest of gigantic trees in California, and prove, except by analogy, that these princely forms were ever mere seedlings.

One of the ablest of the defences of Christianity is Butler's" Analogy."

II. Abrupt Appearance of Species.

The fact that geological history can be divided 'into periods, appears to militate against a gradual development of the species of one epoch into those of another. At first thought, it would seem that, upon the theory under discussion, there ought to be such a minute and continuous gradation of species from beginning to end of the geological formations that the divisions of the strata into Palaeozoic, Mesozoic, and Cainozoic should be altogether arbitrary. Innumerable forms of transitions must have existed. Why have they disappeared? Why, in fact, are the beginnings of these periods so abrupt?

Barrande, one of the most eminent of modern palaeontologists, has pressed this objection with great force in his work on the Trilobites of the Silurian epoch. This widely extended family of Crustaceans appears suddenly and in a highly developed form. If we except the still controverted Eozoon Canadense, the Trilobite is one of the oldest forms of life whose remains have thus far been discovered. Yet hundreds of species swarmed in the Cambrian and Silurian seas of Europe and America, and the remarkable eyes of these animals were apparently as well developed in the earlier,

as in the later, periods of the existence of the family. If these species were transmuted from previously existing and lower organisms, why are there no premonitions of their approach in the epochs immediately preceding? But there is no direct evidence that they had any ancestry.1

Again, fishes appear with equal abruptness in the Devonian formation. Below the very uppermost divisions of the Silurian system not a single bone of any aquatic animal of the Vertebrate class has been detected. Yet in the Old Red Sandstone, immediately above the Silurian, there are found the fossil remains of more than a hundred species to which the anatomist would assign "by no means a low place in the Piscene class." 2

Again, "The transition from the Palaeozoic to the Mesozoic forms of life was strongly marked in geological history." "At the close of the Carboniferous age there was a complete extermination of all living species.' 993 In this step upward we have passed from the age of fishes to the age of reptiles with an abruptness that is somewhat startling to any theory of transmutation, and especially to a theory one of whose fundamental principles

1 See Summary of Barrande in Winchell, pp. 125–144.

2 See Lyell, Principles of Geology, Vol. i. p. 151 f. Also, Hugh Miller, Footprints of the Creator.

8 Dana, Manual of Geology (1st ed.), pp. 413, 403. The second edition is much more guarded and omits this with many other like sweeping assertions.