impassable obstruction; different bloods are differently constructed, and cannot be injected into veins of different animals without fatal consequences.

If the blood introduced into the veins of a living animal differs merely in the size, not in the form of its globules, a disturbance or derangement of the whole economy, more or less remarkable, supervenes: the pulse is increased in frequency, the temperature falls rapidly, the alvine secretions become tinged with blood, and death generally happens after the lapse of a few days. The effects produced by the injection of blood having circular globules into the veins of an animal the globules of whose blood are elliptical, or vice versâ, are still more remarkable; death then usually takes place amidst nervous symptoms of extreme violence, and comparable, in their rapidity, to those that follow the introduction of the most energetic poisons.*

The application of these facts as an answer to the Theory of Transmutation is obvious, as the supposed change of animals would have to encounter this obstacle, and to admit into the veins of the transforming animal a stream of death in parting with its own proper original stream of life. In that Theory it is gravely suggested that the bird came out of the reptile, partly owing, it is to be presumed, to their contemporaneous appearance in geological record, and partly to some peculiarity of internal structure. We hear on good authority that 'the crocodile is the connecting link between Reptiles and Birds, and in almost every part of its body it presents a type of structure almost intermediate between the two. The stomach of this creature might, in fact, be almost mistaken for the gizzard of a rapacious bird. The

* Milne Edwards, who refers to the experiments of Messrs Prevost and Dumas.

æsophagus terminates in a globular receptacle, the walls of which are very muscular, and the muscular fibres radiate from a central tendon precisely in the same manner as those of a bird,'* &c. This is quite enough for a Transmutationist; with this degree of similarity the next step to the change of the reptile into the bird would be very easy. In this school similitude, with sufficient time intervening, is the same thing as metamorphose.

In a common-sense view of the subject such a transition must appear, of any that could be suggested, the least probable for, taking reptiles as we find them, and especially the crocodile, we should, without the revelations of anatomy, be unable to find in that animal any the most distant resemblance to a bird of prey, except in its rapacity and ferocity. Comparative anatomy, however, detects many unsuspected facts; but still, even with this evidence of comparative anatomy, we should say, in the supposition of such a change as this, that a cold-blooded animal had to be transformed into one of the warmest temperature; that a tripartite heart had to be changed into one of four cavities; that an animal of the lowest respiration had to pass into a process of the highest; and to assume a blood of different-sized particles, though such a change is, as we have seen, decreed to be impossible by a law of Nature.

To these difficulties we should have to add the change of the animal's nature in the view of character. The reptile that leaves its progeny to chance, and is indifferent to its existence, would have to assume a disposition characterized by strong affection to the young brood, with a heart more changed in a moral aspect than the other physical change of the great pulsatory cavities of circulation.

Jones, Animal Kingdom, 562.

In addition to all these considerations there would be the total change of the whole creature in its aspect, the use and destination of its limbs, the wonderful remodelling of the limbs, its general habits, and all its relation to the external world. Comparative anatomy, therefore, helps the Transmutationists but little; on the contrary, it seems to increase their difficulties, by approximating animals in certain points, and bringing them as it were together, as if to make manifest the exceeding great difference and strong dissimilarity in general character and habit. It has done this in the instance of the man and the ape, and in Mr Darwin's favourite example, the horse and the tapir, and here we have it again in the reptile and the bird.

In the mean while, in spite of these similarities of comparative anatomy, there are organic distinctions, as we have seen, which interpose with a strong prohibition in the scheme of gradual change; and these distinctions are of

*The bones of birds, especially those of flight, present the opposite extreme of lightness; not but that the osseous tissue itself is more compact than in most mammalia, but its quantity in any given bone is much less, the most admirable economy being traceable throughout the skeleton of birds in the advantageous arrangement of the weighty material for the office it is destined to perform. Thus in the long bones, the cavities, analogous to the medullary in mammals, are more extensive, and the solid walls of the bone much thinner. A large aperture called the foramen pneumaticum, near one or both ends of the bone, communicates with its interior, and an air-cell or prolongation of the lung is continued into aud lines the cavity of the bone, which is thus filled with rarefied air instead of mar row. The extremities of the bone, instead of being occupied by a spongy diploë, present a light open network, slender columns shooting across in different directions from wall to wall, and these columns are likewise hollow. The vastly-expanded beak, with its hornlike process, in the Hornbill, forins one great air-cell, with thin bony parietes: and in this bird, in the Swifts, and the Humming Birds, every bone of the skeleton, down to the phalanges of the claws, is pneumatic.'—Owen.

·

We cannot but admire the great ability, science, and skill exhibited by Mr Darwin's Sequence of events as observed by us,' in producing such a structure, and the more so as it has been produced without object, aim, or design. In Mr Darwin's theory the bones of a bird are a lucky hit, one of the best throws in the game of chance ever recorded.

greater weight in the scale of life than the anatomical analogies.

Mr Darwin, who does not tell us from what antecedent animal a bird was formed, seems to think that the only dif ficult point in the manufacturing of birds was making a pair of wings, just, we may presume, as Dædalus supposed, when he fabricated wings for his ill-fated son: but everything in the bird, if elaborated out of some other animal, had to be changed,-many important points of its internal structure, the circulation of its blood, its lungs, its respiration, the form of its bones, the texture of its bones, its skeleton, its muscles, the arrangements and number of its nerves, the mould and texture of its eye, its mind and its will; and all changed simultaneously, if ever such a dream was realized as the mutating a wingless animal into one that could soar into the air with plumed body and wings.

*

'It might require a long succession of ages,' says Mr Darwin, to adapt an organism to some new and peculiar line of life, for instance, to fly through the air, and consequently the transitional forms would often long remain confined to some one region: but when this adaptation had once been effected, and a few species had thus acquired a great advantage over other organisms, a comparatively short time would be necessary to produce many

*Cuvier's description of the eye of the bird deserves attention: 'L'œil des oiseaux est disposé de manière à distinguer également bien les objets de loin et de près; une membrane vasculeuse et plissé, qui se rend du fond du globe au bord du cristallin, y contribue probablement en deplacant cette lentille. La face anterieure du globe est d'ailleurs renforcée par un cercle de pièces osseuses; et, outre les deux paupières ordinaires, il y en a toujours une troisième placée à l'angle interne, et qui, au moyen d'un appareil musculaire remarquable, peut couvrir le devant de l'œil comme un rideau. La cornée est très convexe, mais le cristallin est plat, et le vitré petit.'

The compartiely than time and the rapidity are, indeed, skiet invasions of the fundamental law of the system, for Mr. Darwin has repeatedly hid it down that

Natural Selection aŭıraya acta very slowly' 114; but in this history of birds there was much to account for, as the feathered tribe is rich in orders, families, genera, species, and sub-species, and to concede the usual measure of time which the Theory requires, for each distinct species, would be making too large a demand even on the millions of