A

B

a

sciences; it is a mere description of nature. But it yields a far more accurate knowledge. In many cases it discloses, for the first time, the significance of organs, and gives to comparative anatomy the confirmation, and frequently the possibility of interpretation. The wing of a bird, in its individual parts, may be traced back without difficulty to the anterior extremities of a reptile or a mammal. But the leg of a bird, as a complete organ does not harmonize with the leg of other vertebrata until the development of the bird in the egg reveals that the disposition of the segments and of the articulations is precisely the same in both cases, and that the apparent anomaly is produced merely by the subsequent anchylosis of bones, which generally remain separate.

The complete leg of the bird (A) shows us at a, the femur, or thigh bone, and at b, the tibia, or lower leg bone; but instead of the bones of the tarsus and metatarsus, the latter of which

affords attachment to the

FIG. I.

m

n

toes, we find only the long bone c, and at its lower

extremity a small bone supporting the four toes. Earlier writers were content to say that the astragalus (c) replaces the tarsus and metatarsus. But this is not the case; for the chick in the egg (B) shows that the bird's leg consists of the thigh, or femur (a), and the shank or tibia (b), two tarsal (m n), and three or four metatarsal bones (c), and the toes, or phalanges; that the upper tarsal bone is anchylosed with the tibia, and the lower one with the consolidated metatarsus. Only thus do we obtain a true perception of the fact manifested in A, although the cause of the fact does not as yet

appear.

The next example is rather more difficult. Without the history of development, comparative anatomy is incapable of explaining why man possesses three little bones in the auditory apparatus, the bird only one. The history of development shows that out of the material which in man is applied to the formation of the malleus and incus, two other portions of the skull are evolved in the bird, having little or nothing to do with the auditory mechanism. In short, the history of development, which describes the gradual formation of the organism, is at every step a beacon to comparative anatomy. In itself, however, the history of development does not as yet exceed the rank of a merely descriptive branch of erudition.

But if we now perceive how the evolutionary stages of individuals represent series from the lower to the higher, analogous to the various members existing side by side in the same group of animals,-how, for instance, the mammal passes through stages at which the lower vertebrata remain fixed,-a connection, at first sight

mysterious, is indicated between the evolution of the individual and the general constitution of the animal. world. This connection requires a scientific solution, a reduction to causes, and this all the more urgently because their relations, though as yet hidden, are rendered more probable by a third series of phenomena, the conquest of which is likewise the achievement of natural history. We allude to the record of the primæval world.

Therefore, the knowledge of palæontological facts also forms part of the indispensable basis of our operations. Geology entered the right track forty years. ago. We now know that the world was not made backwards, but originated by gradual formations and metamorphoses; we may-nay, we must, infer that, at a definite epoch of refrigeration, life appeared in a natural manner, that is to say, without any incomprehensible act of creation; and during this slow transformation of the earth's crust, we see living beings also gradually increasing, differentiating, and perfecting themselves.

Yet more. As was first convincingly proved in detail by Agassiz, one of the most vehement antagonists of the theory of descent, we behold the palæontological or historical series of organisms in the same sequence as the phases of the development of the individual. There are here vast chasms yet to be filled up by future observation, though in many points we must not altogether despair of success. But that the process of palæontological development is, in general, the one indicated, is disputed only by naturalists, who, like Barrande, years ago anchored themselves to inalterable convictions in science, as in creed, to dogmas.

These groups of facts, thus mutually referring to each other, must be, in some degree, examined by any one desirous of understanding them. In other words, we must first review this vast material, before we turn our attention to the magic spell which sifts and makes it comprehensible. The toil is great, but the reward is glorious! For, as regards the organic world, the craving inherent in the human mind for the knowledge of reasons -the need of causality, is satisfied singly and solely by the doctrine of Descent. As yet we do not regard it as complete; in many special cases it still owes us an answer; but, on the whole, it does as much as any other ingenious theory has done; it interprets by a single principle those great phenomena which without its aid remain a mass of unintelligible miracles. In a word, it raises the knowledge of organic nature to a science. Even now much of mere professional knowledge is wont to style itself science. But as the doctrine of Descent includes all life, it cannot stop on approaching Man. Were we doubtful as to the origin of language, or even forced to admit total ignorance on this point, we could not, from the existence of language, deduce the inapplicability to man of the doctrine of Descent, without, as it seems to us, arbitrarily breaking the chain of ratiocination.

We will now return to the preliminary question already indicated, as to the limits of the investigation of nature. It is the more important, as incompetent judges are wont to assert, that these limits are exceeded. The frivolity of the logic by which such accusations are rendered plausible to the multitude surpasses all licence. We open, for instance, Luthardt's "Apologetic Lectures on the Fundamental Truths of Christianity," ("Apolo

getische Vorträge über die Grundwahrheiten des Christenthums,") and see how he defends the reality of miracles. "Miracles," he says, "are not even miracles. They do not even repeal the laws of nature; they merely release single occurrences from the dominion of those laws, and place them under the law of a higher will and a higher power. Of this we have many analogies in lower spheres. If my arm hurls a stone into the air, this is contrary to the nature of the stone, and is not an effect of the law of gravitation, but the interposition of a higher power and a higher will, producing effects which are not the effects of the inferior powers. These powers and these laws are not hereby repealed, but still subsist."

Let us pause a moment. To say that it is contrary to the nature of the stone that gravity should be apparently overpowered for a few moments by muscular agency, is physically absurd. The stone remains the same weight, its nature is wholly the same, even while in the motion of projection; and it is utterly unjustifiable and sophistical to prate about muscular force as a higher power opposed to gravity. If the stone weighs two hundred-weight, where is the higher power then?

But when the champion of supernaturalism has misled and prepared his hearers by his worthless analogy, he proceeds: "Thus in the miracle, a higher causality interposes, and evokes an effect which is not the effect of the concatenation of those lower causalities, and yet subsequently submits to these concatenations. But this higher causality ultimately coincides with the highest moral objects of existence. To serve them is nature's highest and most glorious pursuit. Therefore if miracle