Those animals whose anatomical structure closely resembles ours, not to say that it is exactly analogous to ours, such as cattle and sheep, give proof of a moral activity that is insignificant beside the real genius shown by the bee and so many other insects whose nervous systems are still rudimentary in comparison with those of the mammals. Certain sea animals, the barnacles, have suffered, because of their sedentary existence, an anatomical regression. We know that the mobile larvæ of the barnacles possess more complicated organisms than those of the adult and stationary animal. To conclude from that that this anatomical regression is a lowering of the species is to assume a great deal, and it is to accord to movement a very debatable significance. There exist species of plant life, especially among the conifers and the ferns, which, for thousands of centuries, seem to have remained in an almost stable anatomical and functional stage. These species are none the less very widely scattered and very long-lived, very adaptable. They offer an outward appearance of happiness and prosperity. On the other hand, nothing permits us to affirm that certain species, like the orchids, which have undergone a delirious evolution resulting in forms of extreme anatomical complexity, have attained a true progress, have improved, that is to say, their moral destiny: we see them subject to innumerable external servitudes. Their reproduction, even, is only possible thanks to the intervention of outside agencies and is fraught with perils. A seductive argument that smacks of anthropomorphism inclines us to believe that these species, intoxicated with their material difficulties, ought to have a less free and less serene philosophical existence. The complexity of the individual organism, which corresponds strictly to the political, economic and scientific complexity of societies, adds neither to the possibilities of life, nor to its scope of activity, nor to its hopes. Certain fish, the pleuronectes, have sought their salvation in a very bold, precocious development that ends in a displacement of their eyes, of their mouth and in a profound disorder of their original symmetry. Looking at them, one has the impression that this development has thrown them into an impasse, into a _cul-de-sac_ from which it would be difficult for them to escape into a new evolution; one has the impression that this whole biological stratagem has considerably restricted the destiny of the species. Besides, and the naturalists know it very well, the species that are most highly evolved, most differentiated, to employ the consecrated expression, are in a certain sense the oldest species, imprisoned in their own tradition and scarcely to be counted upon for a new adaptation, a profound reformation of their organs and their habits. IV