grades and greater perfection as a physiological problem; and to shew that in the buried worlds of life this continual expansion of the general fundamental form, with a continual tendency to higher and higher development, can be placed in evidence as a matter of history. It is important to keep this distinction in mind.

DEVELOPMENT.

The author of the Vestiges of Creation placed before the English reader some sketches of the aspect of the animated world in successive geological ages, and has proposed in relation to the vegetable and animal kingdoms a full hypothesis of development to fit the gradation from the simple Lichen and Animalcule respectively up to the highest order of Dicotyledonous trees and the Mammalia. He attributes a great amount of change to the necessary effect of variations in the physical conditions which are influential on life: this change being progressive from lower to higher grades, and unlimited except by the range of physical conditions.

'While the external forms of the various vertebrate animals are so different, the whole are, after all, variations of a fundamental plan, which can be traced as a basis through the whole, the variations being merely modifications of that plan to suit the

particular conditions in which each particular animal has been designed to live. Starting from the primeval germ, which is the representative of a particular order of full-grown animals, we find all others to be merely advances from that type, with the extension of endowments and modification of forms which are required in each particular case: each form, also, retaining a strong affinity to that which precedes it, and tending to impress its own features on that which succeeds.

"The various organic forms of our world are bound up in one-a fundamental unity pervades and embraces them all, collecting them, from the humblest lichen up to the highest mammifer, in one system, the whole creation of which must have depended upon one law or decree of the Almighty, though it did not all come forth at one time. The idea of a separate creation for each must appear totally inadmissible. The single fact of abortive or rudimentary organs condemns it; for these, on such a supposition, could be regarded in no other light than as blemishes or blunders, the thing of all others most irreconcileable with that idea of Almighty Perfection which a general view of nature so irresistibly conveys. On the other hand, when the organic creation is admitted to have been effected by a general law, we see nothing in these abortive parts but harmless

peculiarities of development, and interesting evidences of the manner in which the Divine Author has been pleased to work,

"The whole train of animated beings, from the simplest and oldest up to the highest and most recent, are thus to be regarded as a series of advances of the principle of development, which have depended upon external physical circumstances to which the resulting animals are appropriate. I contemplate the whole phenomena,' he says, 'as having been in the first place arranged in the councils of the Divine Wisdom, to take place, not only upon this sphere, but upon all the others in space, under necessary modifications, and as being carried on, from first to last, here and elsewhere, under immediate favour of the creative will or energy. We are drawn to the supposition that the first step in the creation of life upon this planet was a chemicoelectric operation, by which simple germinal vesicles were produced.' After this it is suggested, 'as an hypothesis already countenanced by much that is ascertained, and likely to be further sanctioned by much that remains to be known, that the first step was an advance under favour of peculiar conditions, from the simplest forms of being, to the next more complicated, and this through the medium of the ordinary process of generation.'

I am relieved from the necessity of pointing out on how slight a basis these bold assumptions are rashly poised, by the opportunity of referring to the full and complete examination of the whole argument, in the Discourse on the Studies of the University of Cambridge, by Professor Sedgwick. In this luminous treatise, the hypothesis of development has been met at every point, on physiological and geological evidence; palæontology has been surveyed from a high point of view; the latest discoveries of Forbes, Falconer, and Owen, bearing on the subject, have been ascertained; and the true succession of physical phenomena has been traced through the long periods of time embraced by geology. From this large investigation, the general conclusion is that 'Geology, not seen through the mists of any theory, but taken as a plain succession of monuments and facts, offers one firm cumulative argument against the hypothesis of development'.'

CONSTANCY OF SPECIES.

It is curious to contrast with these views of the unlimited mutability of species, the conclusions of an anatomist and naturalist, who is so little fettered by ordinary formulæ, as to admit in the genus Homo,

1 Studies of the University of Cambridge. Preface, p. cxxviii. edit. 5.

sixteen distinct species. In discussing the geographical distribution of these families of men, and the animals associated with them, M. Charles Desmoulins1 takes occasion to affirm in the strongest manner the constancy of specific forms, unimpaired by time and physical changes:

'In future it will be vain to contest the inalterability of species, by means of the thousand and one suppositions suggested by ignorance or deception. For example, the carp and the barbel, which differ much less one from the other than a Negro and a Frenchman, have the central parts of their nervous system, different in number, differently arranged and shaped. Evidently cold, heat, light, obscurity, exercise, repose, more or less food, &c. have had no influence on that.

'A single objection has been offered to the certainty of these results, and this objection is merely a supposition. It is supposed that the actual diversity of species depends on an alteration of primitive forms, either by climate, or by the crossing of allied species, which would thus have multiplied differences, which were afterwards strengthened by time, so that the actual species would be for the most part only accidental varieties rendered definite, one knows not how.

1 Hist. Nat. des Races Humaines, 1826.