Another system, supported by the most illustrious names, makes of man a sort of special entity, differing from other organised beings by the distinct and clear nature of his intelligence. It is an opinion adopted and defended to the last by a learned man, to whose memory we cannot, _en passant_, prevent ourselves from rendering the homage which is his due, Isidore Geoffroy Saint-Hilaire. We find in the second volume of his _Histoire Naturelle Générale_, almost a return to Cartesian ideas. According to him animals do not think, they possess only that sensibility that plants have not.[23] And the celebrated naturalist agreed with the adoption of a human kingdom, appearing as the crowning-point of the organic and inorganic kingdoms,[24] and as distinct from the second as this is from the third. Before proceeding further, we may be permitted to make one preliminary remark. We may thus declare it:-- PROPOSITION.--_Man nearly approaches the Anthropomorphous Apes in his Physical Organism._ Whether one is a partisan or not of the “Human Kingdom,” this resemblance is a fact which it will be in no person’s ideas to contest. And it is not merely in the external forms; we find it even greater if, going to the foundation of the facts, we give our attention to the essential parts composing the body,--to the anatomical elements,--to those delicate particles visible only in the microscope, and which always show, among animals of the same group, a marvellous uniformity. It is here where, if not an impossibility, at least a sort of contradiction presents itself to the defenders of the “human kingdom;” for there are two organisms, scarcely different, at the service of two directing powers, of two intelligences absolutely and radically dissimilar. Doubtless all the forces of organised matter are not known to us, but does not this resemblance, though even a superficial one, surprise us; and does it not seem that every organism constituted directly by reason of the influences which it is qualified to receive or to transmit, ought to vary like these influences, and in the same proportion? It is very easy to admit that there is more distance between the intelligence of man and that of the anthropomorphous apes, than between the intelligence of these last and that of the smooth-brained squirrel, and that at the same time the immense distance is only marked in the first case by very superficial variations of the organ of intellectual manifestations, whilst, in the second case, this lesser distance is explained by enormous differences. To admit, with Bossuet,[25] that this superior intelligence, the appanage of man, is not attached to the organs reserved for the manifestations of this inferior intelligence common to man and animals, is to return to Descartes, and this is to fall again into new difficulties. Will this superior intelligence, thus detached from the material world, be then inaccessible to physical violence?