separated succession of the evidence in its favour, that is to say, of the systems of stratification, the fixed conception of a fossil was, that whatever had lived before the appearance of man on the threshold of the Alluvial period was fossil. It has been proved that the existence of man is far more ancient; that species and races which surrounded the cradle of mankind have become extinct; hence that they, like the Mammoth, for example, are fossil to us only, and not to our diluvial forefathers; while many other animal forms which existed before man have been preserved till now. On the whole, from the Tertiary period forwards, the herbivorous Mammals. precede the Carnivora. The monkeys appear only shortly before man.

Notwithstanding many gaps in the palæontological record, the progress of development is manifest in the organic world, including the vegetal kingdom. No fossil animal controverts the system. On the contrary, the most varied adjustments and accommodations are afforded by the antediluvian animals. If, for instance, the present Pachyderms are sharply distinguished from the Ruminants, an unbroken bridge between them is established by the extinct forms. If the present time shows us only single scattered genera of the Edentata, the Diluvial period exhibits a considerable number under far more heterogeneous forms. Thus in the types as in the divisions of the classes, the system advances from the older to the more recent periods; while the more ancient groups gradually increase and then diminish, as newer, more perfectly or specifically integrated forms, are interposed. The former either vanish entirely or outlast the more recent periods, and continue in scanty remnants down

to the present day. The formations mostly have their characteristic organisms, but almost everywhere the connecting links have been exhibited. Everything conduces to show that it is a question of evolution, not revolution. Wherever there seems to be a sudden break, the case is the same as in the revolutions of human history, in which likewise only reforms long-prepared, and practically necessary, come to a rapid issue.

If we sum up the result of the comparison of fossil with living animal life, we are first of all struck by the accordance between the grades succeeding one another in the order of time, and the members now ranged side by side in the system. Secondly, when this is confirmed, the parallelism between the geological succession of animals. and the grades of the individual development of present animals follows as a matter of course. Agassiz, in his great work on fossil fishes, pointed out this fact with irresistible force, and confirmed it in his later writings by renewed, valuable, and convincing observations on the investigations of the development and growth of corals. The same examples which served in the preceding chapter to illustrate the parallelism of individual development with the systematic stages, may be repeated here; though many newer and very striking instances. have been brought to light by the special researches of the last ten years. To express this relation, Agassiz introduced the term "embryonic types," or "embryonic representatives." Thus the stalked stone-lilies are the embryonic types of the present genus Comatula; the most ancient Echinæ are the embryonic representatives of the higher families of the Clypeastra and Spatanga; the Mastodon, on account of its persistent molar teeth,

is the embryonic type of the elephant, which only transitorily possesses such teeth. If the term implies nothing further than the vague assertion of "the working of the same creative Mind through all times and upon the whole surface of the globe," 12 scarcely any solution is obtained. Let us rather, with Rütimeyer in his admirable researches on fossil horses,13 allow our attention to be drawn by these and similar facts "to a close connection between the phases of development in the individual and in the species," that is, to a natural connection.

All who absolutely require a personal God in the current history of creation, draw from these facts no other inference than that their God had the whim of producing at first imperfect and subsequently more and more perfect organisms, and of applying in the development of the last reminiscences of the first.

As worthless as the formula of embryonic types is another, invented by Agassiz, for the shapes in which, in some fossil groups, mechanical and physiological results were imperfectly obtained, and for which provision is made in later organisms by other more adequate and perfect arrangements. These are his "prophetic types." The Pterodactyl is, for example, supposed to stand in this relation towards the bird. Does this quibble aid in the comprehension of either one or the other? Is any rational idea obtained if, besides the prophecy of the Pterodactyl, the geologically antecedent insect is regarded as its prophet, or the bird as the forerunner of the bat? There is no sense at all unless the prophet becomes the progenitor, which in these cases cannot be supposed.

V.

The Standpoint of the Miraculous, and the Investigation of Nature-Creation or Natural Development-Linnæus-Cuvier-Agassiz-Examination of the Idea of Species.

"I hear your message well, it cannot wake my faith.

To faith is miracle her dearest child."*

HAVING quoted these words of Faust, we will proceed without further digression to examine the standpoint occupied by the Natural Philosopher with regard to a domain where the sceptre is wielded, not by the lucid intellect, but by the imagination looking through coloured glasses; not by Logic, but by arbitrary ideas; where the laws of causality are turned upside down; a domain where, indeed, many unquestionably honourable men still feel themselves at home, but which at best fosters only pious self-deception, and indolence of mind.

We must take up a decided position without regard to consequences, as after the discussion of the actual record of the animal world in its three aspects, namely, its present tenantry of complete forms, the evolution of the individuals, and the historical succession during the earlier periods of the earth's formation,—after this superficial work of registration and enrolment, the actual study of our subject must begin.

*Die Botschaft hör'ich wohl, allein mir fehlt der Glaube.
Das Wunder ist des Glaubens liebstes Kind."

This is, however, the case only with those to whom the miracle of creation is absolutely without existence; whereas an observer, who regards any miracle, however slight, or any sort of disturbance of the order of nature, as possible, must deem his science of Biology complete with the erudition formerly propounded, and subsequently extended by countless items of special information. We cannot therefore do otherwise than give to Goethe's maxim, "Belief is not the beginning, but the end of all knowledge," the interpretation that belief is incompatible with knowledge, and that hence belief in a creation of life is incompatible with the investigation of it.

But if Life did not originate in an incomprehensible manner, it must have been developed. Many decades elapsed before this idea with its consequences could be stated; and in order to comprehend the obstinacy with which the contrary was maintained, and a circle of opinions allowed to take root, against which modern Biology alone has waged a successful war, it is necessary to call to mind some of the chief epochs in the history of Geology, and their representatives. This will naturally lead us to the point whence the shaft of knowledge has been sunk.

After the middle of the last century, Comparative Anatomy, almost independently of systematic Zoology, took a prosperous course, and became far richer in ideas than this descriptive Natural History. One of its maxims, however, was accepted without examination— the constancy and immutability of species; and this maxim forms the centre of the views entertained by Linnæus. The continued authority of this great de