In one of his admirable little textbooks, intended to teach and to popularize science, he complacently enumerates the happy modifications effected by that "sublime magician," selection as understood by Darwin. He evokes the metamorphoses of the potato, which, on the mountains of Chili, is merely a wretched venomous tubercle, and those of the cabbage, which on the rocky face of oceanic precipices is nothing but a weed, "with a tall stem and scanty disordered leaves of a crude green, an acrid savour, and a rank smell"; he speaks of wheat, formerly a poor unknown grass; the primitive pear-tree "an ugly intractable thorny bush, with detestable bitter fruit"; the wild celery, which grows beside ponds, "green all over, hard, with a repulsive flavour, and which gradually becomes tenderer, sweeter, whiter," and "ceases to distil its poison." (9/2.) With profound exactitude this great biologist has also perceived the degree to which size may be modified; may dwindle to dwarfness when a niggardly soil refuses to furnish beast and plant alike with a sufficient nourishment. Without any communication with the other scientists who were occupied by the same questions, knowing nothing of the results which these experimenters had attained in the case of small mammiferous animals, and which prove that dwarfness has often no other cause than physiological poverty, he confirmed and expanded their ideas from an entomological point of view. (9/3.) Scarcely ever, indeed, was he first inspired by the doings of others in this or that direction; he read scarcely anything, and nature was his sole teacher. He considered that the knowledge to be obtained from books is but so much vapour compared with the realities; he borrowed only from himself, and resorted directly to the facts as nature presented them. One has only to see his scanty library of odd volumes to be convinced how little he owes to others, whether writers or workers. A true naturalist philosopher, this profound observer has also thrown a light upon certain singular anomalies which, in the insect world, seem to constitute an exception, at all events in our Europe, to the general rules. It is not only to the curiosity and for the amusement of entomologists that he proposes these curious anatomical problems, but also, and chiefly, to the Darwinian wisdom of the evolutionists. Why, for example, is the Scarabaeus sacer born and why does it remain maimed all its life; that is to say, deprived of all the digits on the anterior limbs? "If it is true that every change in the form of an appendage is only the sign of a habit, a special instinct, or a modification in the conditions of life, the theory of evolution should endeavour to account for this mutilation, for these creatures are, like all others, constructed on the same plan and provided with absolutely the same appendages."