Also in “l’integration croissante de la force evolutive a mesure qu’elle se partage dans les formes produites, et la decroissance proportionelle de la plasticite de ces formes a mesure qu’elles s’eloignent davantage de leur origine, et qu’elles sont mieux arretees.”  As they get older, they gain in fixity through the operation of the fundamental law of inheritance; but the species, like the individual, loses plasticity and vital force.  To continue in the language of the original: 

“C’est dire qu’il y a eu, pour l’ensemble du monde organique, une periode de formation ou tout etait changeant et mobile, une phase analogue a la vie embryonnaire et a la jeunesse de chaque etre particulier; et qu’a cet age de mobilite et de croissance a succede une periode de stabilite, au moins relative, une sorte d’age adulte, ou la force evolutive, ayant acheve son oeuvre, n’est plus occupee qu’a la maintenir, sans pouvoir produire d’organismes nouveaux.  Limitee en quantite, comme toutes les forces en jeu dans une planete ou dans un systeme sideral tout entier, cette force n’a pu accomplir qu’un travail limite; et du meme qu’un organisme, animal ou vegetal, ne croit pas indefiniment et qu’il s’arrete a des proportions que rien ne peut faire depasser, de meme aussi l’organisme total de la nature s’est arrete a un etat d’equilibre, dont la duree, selon toutes vraisemblances, doit etre beaucoup plus longue que celle de la phase de developpement et de croissance.

A fixed amount of “evolutive force” is given, to begin with.  At first enormous, because none has been used up in work, it is necessarily enfeebled in the currents into which the stream divides, and the narrower and narrower channels in which it flows with slowly-diminishing power.  Hence the limited although very unequal duration of all individuals, of all species, and of all types of organization.  A multitude of forms have disappeared already, and the number of species, far from increasing, as some have believed, must, on the contrary, be diminishing.  Some species, no doubt, have suffered death by violence or accident, by geological changes, local alteration of the conditions, or the direct or indirect attacks of other species; but these have only anticipated their fate, for M. Naudin contends that most of the extinct species have died a natural death from exhaustion of force, and that all the survivors are on the way to it.  The great timepiece of Nature was wound up at the beginning, and is running down.  In the earlier stages of great plasticity and exuberant power, diversification took place freely, but only in definite lines, and species and types multiplied.  As the power of survival is inherently limited, still more the power of change:  this diminishes in time, if we rightly apprehend the idea, partly through the waning of vital force, partly through the fixity acquired by heredity—­like producing like, the more certainly in proportion to the length and continuity of the ancestral chain And so the small variations