“It is evident, that if some well authenticated facts could have been adduced to establish one complete step in the process of transformation, such as the appearance in individuals descending from a common stock, of a sense or organ entirely new, and a complete disappearance of some other enjoyed by their progenitors, that time alone might then be supposed sufficient to bring about any amount of metamorphosis. The gratuitous assumption, therefore, of a point so vital to the theory of transmutation, was unpardonable on the part of its advocate[9].” The transmutability of species is a point which has been maintained by many naturalists besides Lamarck, and the reasons they have adduced in support of their opinions are so various, that the full consideration of them would be inconsistent with our present purpose. It may be assumed as capable of most satisfactory proof, that the mutations which species undergo in accommodating themselves to a change of external circumstances, have a definite limit, and are regulated by constant laws; and that the capability of so varying, forms part of the specific character. Indefinite divergence from the original type is guarded against, in the case of intermixture of distinct species, by the sterility of the mule offspring; circumstances which show that species were designed to retain the individuality of character with which they were endowed at the time of their creation, and that they have a real existence in nature[10]. The intellectual faculties of animals, Lamarck regards as entirely the result of organization. Even in the case of the most perfect of them, the human species, there is no distinct recognition of a spiritual substance derived from heaven; and all intellectual phenomena whatever, are ascribed to some physical cause. Nature, he conceives, offers nothing cognizable by us but _body_; the movements, changes, and properties of _bodies_, form the only field open to our observation, and the only source of real knowledge and useful truths[11]. The place of the soul seems to be usurped by a certain _interior sentiment_, to which he continually refers, as exercising a most powerful influence over all the faculties, and giving rise to all the passions and affections[12]. Thus the noblest faculties of the mind, “the capability and godlike reason,” by which we are distinguished from other animals, ----and this spirit, This all-pervading, this all-conscious soul, This particle of energy divine, Which travels nature, flies from star to star, And visits gods, and emulates their powers; are made to emanate from a certain relation of parts and organs,--a particular conformation of material substances, just as a desired result is obtained by arranging in a certain order the parts of a piece of mechanism.