but also by the close relationship of the subjects of which they treat, and the common object proposed.

Mr. Darwin attempts to show, that all animals now in existence have been derived from the lowest and simplest forms of life, by transmutation of species acting through illimitable periods of time.

Mr. Huxley adopts this doctrine of transmutation, and thinks that he has proved that Man is the nearly allied if not immediate descendant of the Gorilla.

Sir Charles Lyell accepts, with approbation, slightly modified, these views of his friends, and undertakes to furnish them, from the records of Geology, all the time demanded by their speculations.

We propose to briefly review each of the above works, with a view to determine how much of scientific truth and philosophy each is entitled to claim. Preparatory to this task, wé desire to give expression to some thoughts in regard to the nature and distinction of Species,-as this is the main subject of the first two works we intend to review.

The question of Species-its origin, nature, and limits,has always been a most vexed subject of dispute, upon which naturalists are now divided, and will probably always differ in their views. We may observe the facts connected with its phenomena, note its distinctions, and speculate on its nature, but the laws which govern its Origin and Extinction are beyond the reach of Philosophy. Its causation, if not revealed, must ever remain hidden in the mind of the Creator-for Science holds no clue to guide her groping steps. Where Science ends, Faith begins.

Prof. J. D. Dana, in an Article as profound as it is original, which appeared in the November No., for 1857, of the "American Journal of Science and Arts," has established, in a conclusive manner, the existence of species as "essentially realities in nature." Reasoning from the general to the special, he shews that the true type idea, or notion of species, is not to be found in any one group, but in the potential element which lies at the basis of the existence of each individual of the group. He demonstrates that, in accordance with the universal law which governs all existence, and which pervades all na

ture, this potential element must be a fixed and definite unit, capable of multiplication in the inorganic world, by combination of fixed equivalents, and in the organic world, by selfreproduction. Thus he proves that permanency is a necessary attribute of species, demanded by the harmony of the universal law of existence; and he also shews that variation from the normal type-whatever that may be-is demanded by the universal law of" mutual sympathy," which determines all change of composition or decomposition, growth or decay. Hence he deduces, with great philosophical severity, the essential idea of a species, to be "a specific amount or condition of concentered force, defined in the act or law of creation."

This stringent formula is intended to embrace all the departments of nature; but while it expresses, with severe accuracy, the logical type idea of species, as a real existence, it by no means, as Prof. Dana admits, gives us a conception of the material type form. Though species is a reality, no type idea of it can be represented in any one material existence, nor be designated by any one example. Nor can we ascend, by induction, from a study of the individuals, to a correct conception of the type of the species,-inasmuch as "the variables," as well as "the constants," form an element of the type, and therefore the conception formed from the study of the individuals, is a conception only of its phases or modifications. Nevertheless, we may adopt this stringent formula as a safeguard against specious generalizations.

In applying it to the animal kingdom, we may construe it as meaning,—that specific degree and kind of vital organization necessary for the development of the individual under modifying circumstances, and which is defined by the act or law of its creation.

The above formula defines species in relation to its essence; but it is also desirable to consider it in relation to its manifestations of form, and to accompany the definition with some sure test, whereby to guide and correct our classification of individuals. Considered in this relation, we would define Species to be an original organized form, specific in its kind and immutable in its fundamental characteristics, but capable of developing varieties under modifying circumstances. The in

dividuals of a species constantly reproduce their like with those of the same species; but their offspring, by generation with any other species, is incapable of continuous fertility.

This definition recognizes a special law of being for each individual of a species, stamping immutability upon its generic seminal characteristics, in harmony with the general law of Nature, which determines, with mathematical precision, the component elements of all bodies and forces. But while it thus imposes constancy of fundamental characteristics on all, it allows to each individual great variety of development in accommodation to surrounding circumstances, and in obedience to that universal law of mutual sympathy and reciprocal action, which diversifies with change every department of Nature.

Could we ascertain with accuracy the fundamental seminal characteristics which distinguish one animal from another, we would be able to make our scientific classification of species accord with that distinction which really exists in nature. Our present classifications are, in no small degree, uncertain and arbitrary, based, frequently, on very slight differences of structure, form or color. Thus, for instance, "a slight peculiarity in the coloring of a minute part of the anterior wing" of a butterfly, (Vanessa atalanta,) is sufficient to create a doubt whether it should not be made the basis of a distinct species. So also the African, Indian and fossil Elephant, (E. primigenius,) are made distinct species in consequence of slight discrepancies of form in the markings on the wearing surfaces of their molars; which, in the first, are lozenge shaped, and in the last two, rather more rhomboidal.

Appealing to our present classifications, it is not strange that the advocates of the so-called development theory should find, in Nature, some few facts which apparently support their visionary hypothesis of transmutation of one species into another. These pretended instances of transmutation may be more correctly attributed to individual peculiarities, perpetuated under favorable circumstances, being simply varieties developed under certain conditions, and which present an apparent constancy, so long as the modifying conditions which developed them remain constant. Look at the vast changes that man has wrought by art in many domestic animals, developing

varieties, but never altering species. See the striking differences which separate the races of dogs, many of which occur naturally, and, under given circumstances, are constant. We class the brown and black bear as different species, yet what differences do they present at all comparable to those which distinguish the mastiff from the spaniel, or the greyhound from the bull-dog; or these again from the scent-hounds. So also the varieties of domestic fowls present as marked differences as those which distinguish many individuals of the parrot or grouse family, which are classified as distinct species.

Until the time of Lamarck, the scientific world generally accepted the definition of Linnæus, that "a species consisted of individuals, all resembling each other, and re-producing their like by generation." This definition, though vague, had the merit of fixing, by an infallible test, the line of distinction, but it did not recognize the law of change, by which varieties are developed from the influence of external causes. Lamarck, observing that some fossil "shells were so nearly allied to living species that it was difficult not to suspect that they had been connected by a common bond of descent," proposed to add to the above definition of Linnæus the following clause, viz: so long as the surrounding conditions do not undergo changes sufficient to cause their habits, characters and forms, to change." This addition was very good, inasmuch as it recognized the universal law of change, by which varieties are developed in every department of Nature, within fixed limits. Had Linnæus inserted it in his definition, it would have constituted the basis of a true development theory, and would have precluded the origin of the present transmutation hypothesis.

Lamarck, ignoring Linnæus' great test of distinction, and not duly appreciating Nature's great law of change, fixed his attention exclusively on the varieties developed under this law; and by an unwarrantable generalization of facts, carefully observed, he broached the startling doctrine of progressive transmutation of species, by which the origin of Man, God's master-piece, has been derived from a monkey, through the successive evolutions of a primary monad. According to him, a short-legged bird, constantly desiring to catch fish to

better advantage, gives rise to a race of long-legged waders. In like manner, the camel-leopard has acquired its present shape, by constantly stretching out its neck to reach the higher branches of trees, as the lower ones became scarce. These fanciful lucubrations of Lamarck clearly indicate the origin of Mr. Darwin's hypothesis.

The anonymous author of the "Vestiges of Creation," which appeared in 1844, following closely in the tracks of Lamarck, introduced, as a principal element of change, the force of maternal volition, acting on the embryo, thereby transmuting it into a higher grade than its parent.

Mr. Darwin has somewhat modified these materialistic hypotheses, but it is doubtful whether he has much improved them. To get rid of the imputation, to which the others are liable, of making the orderly arrangement of nature the result of blind chance, he imagines the existence of some vague controlling power, called "Natural Selection," equally blind and materialistic, operating solely through chance variations. He also attempts to get rid of another objection to Lamarck's theorywhich demands a continual creation of monads, by spontaneous generation, to supply the place of those which have been progressively advanced-by arguing that variation is not necessarily progressive, but that, in the struggle for existence, any animal, which has some slight advantage over his fellows, is "naturally selected" for transmutation into some other form, perhaps not superior in organization. This supposition, if true, involves no change of principle, but only a slight difference in the partial working of the machinery of development. The fundamental principle of both hypotheses is the same, viz :—that the Animal Creation has been progressively developed, from the lowest to the highest form, from a Monad to Man.

Mr. Darwin's scheme of creation is based entirely upon the following assumptions :

1st. That "all the organic beings, extinct and recent, which have ever lived on this earth," are the modified descendants, by natural generation, of one common ancestor, and in this common descent, "all have been connected by the finest gradations." His argument for this assumption is an unwarrant