energy to convert into locomotive movement.' It is true that the more the nervous function is perfected, the more must the functions required to maintain it develop, and the more axacting, consequently, they become for them- selves. As the nervous activity has emerged from the protoplasmic mass in which it was almost drowned, it has had to summon around itself activities of all kinds for its support. These could only be developed on other activities, which again implied others, and so on indefinitely. Thus it is that the complexity of functioning of the higher organisms goes on to infinity. The study of one of these organisms therefore takes us round in a circle, as if every- thing was a means to everything else. But the circle has a centre, none the leas, and that is the system of nervous elements stretching between the sensory organs and the motor apparatus.
We will not dwell here on a point we have treated at length in a former work. Let us merely recall that the progress of the nervous system has been effected both in the direction of a more precise adaptation of movements and in that of a greater latitude left to the living being to choose between them. These two tendencies may appear antagonistic, and indeed they are so; but a nervous chain, even in its most rudimentary form, successfully reconciles them. On the one hand, it marks a well-de-
' Cuviereaid; "The nervous syBfem is, at bottom, the whole animal; the other syBtcma are there only to serve it." ("Sur un nouveau npprochement k ^(ahlir entre les classes qui mmposent le regne B.m~ mftl," Arch, du Mutttum d'histoire nalurellr., Paris. 1S12. pp. 73-84.) Of course, it would be neceesary to apply a great many restrictions to this Formula — for example, to allow for the cases of degradation and retrogression in which the nervous eystem passes iDt« the back- ground. And, moreover, with the nen-oua system must be included the sensorial apparatus on the one hand and the motor on the other, between which it acts as iatemcdiary. Cf. Foster, art. "Physiology,'' in the Encyclopatdia BrUanniea, Edinburgh, 1S85, p. 17.
{CHAP.
fined track between one point of the periphery and an- other, the one sensory, the other motor. It has therefore canalized an activity which was originally diffused in the protoplasmic mass. But, on the other hand, the elements that compose it are probably discontinuous; at any rate, even supposing they anastomose, they exhibit a functional discontinuity, for each of them ends in a kind of cross- road where probably the nervous current may choose its course. From the humblest Monera to the best endowed insects, and up to the most intelligent vertebrates, the I progress reahzed has been above all a progress of the ner\-oua 1 system, coupled at every stage with all the new construc- [ tions and complications of mechanism that this progress 1 required. As we foreshadowed in the beginning of this work, the r61e of life is to insert some iTuktermination into matter. Indeterminate, i.e. unforeseeable, are the forma it creates in the course of its evolution. More and more indeterminate also, more and more free, is the activity to which these forms ser\'e as the vehicle. A nervous system, with neurones placed end to end in such wise that, at the extremity of each, manifold ways open in which manifold questions present themselves, is a veritable reservoir of indetermination. That the main energy of the vital impidse has been spent in creating apparatus of this kind is. we believe, what a glance over the organ- ized world as a whole easily shows. But concerning the vital impulse itself a few explanations are necessary.
It must not be forgotten that the force which is evolv-
ing throughout the organized world is a limited force,
which is always seeking to transcend itself and always
remains inadequate to the work it would fain produce. .
The errors and puerilities of radical finalism aie due to
the misapprehension of this point. It has represented
n.i
the whole of the living world as a construction, and a conatmction analogous to a human work. All the pieces have been arranged with a view to the best possible funo- tioniug of the machine. Each species has its reason for existence, its part to play, its allotted place; and all join together, as it were, in a musical concert, wherein the seeming discords are really meant to bring out a funda- mental harmony. In short, all goes on in nature as in the works of hiunan genius, where, though the result may be trifling, there is at least perfect adequacy between the object made and the work of making it.
Nothing of the kind in the evolution of life. There, the disproportion is striking between the work and the result. From the bottom to the top of the organized world we do indeed find one great effort; but most often this effort turns short, sometimes paralyzed by contrary forces, sometimes diverted from what it should do by what it does, absorbed by the form it is engaged in tak- ing, hypnotized by it as by a mirror. Even in its most perfect works, though it seems to have triumphed over external resistances and also over its own, it is at the mercy of the materiality which it has had to assume. It is what each of us may experience in himself. Our freedom, in the very movements by which it is affirmed, creates the growing habits that will stifle it if it fails to renew itself by a constant effort : it is dogged by automa- tism. The most living thought becomes frigid in the for- mula that expresses it. The word turns against the idea.
The letter kills the spirit. And our most ardent enthusi- asm, as soon as it is externalized into action, is so naturally congealed into the cold calculation of interest or vanity, the one takes so easily the shape of the other, that we might confuse them together, doubt our own sincerity,
lOHAP.'
deny goodness and love, if we did not know that the dead retain for a time the features of the living.
The profound cause of this discordance lies in an ir- remediable difference of rhythm. Life in general is mo- bility itself; particular manifestations of hfe accept this mobility reluctantly, and constantly lag behind. It is always going ahead; they want to mark time. Evolution in general would fain go on in a straight line; each special evolution is a kind of circle. Like eddies of dust raised by the wind as it passes, the living turn upon themselves, borne up by the great blast of life. They are therefore relatively stable, and counterfeit immobility bo well that we treat each of them as a thing rather than as a progress, forgetting that the very permanence of their form is only the outline of a movement. At times, how- ever, in a fleeting vision, the invisible breath that bears them is materialized before our eyes. We have this sudden illumination before certain forms of maternal love, so striking, and in most animals so touching, ob- servable even in the sohcitude of the plant for its seed. This love, in which some have seen the great mystery of life, may possibly deliver us life's secret. It shows us each generation leaning over the generation that shall follow. It allows ua a glimpse of the fact that the living being La above all a thoroughfare, and that the essence of life is in the movement by which life is transmitted.
This contrast between life in general, and the forms in which it is manifested, has everywhere the same char- acter. It might be said that life tends toward the ut- most possible action, but that each species prefers to contribute the slightest possible effort. Regarded in what constitutes its true essence, namely, as a transition from species to species, life is a continually growing action. But each of the species, through which life passes, aims
only at its own convenience. It goes for that which demands the least labor. Absorbed in the form it is about to take, it falls into a partial sleep, in which it ignores almost all the rest of life; it fashions itself so as to take the greatest possible advantage of its immediate environment with the least possible trouble. Accord- ingly, the act by which hfe goes forward to the creation of a new form, and the act by which this form is shaped, are two different and often antagonistic movements. The first is continuous with the second, but cannot con- tinue in it without being drawn aside from its direction, fis would happen to a man leaping, if, in order to clear the obstacle, he had to turn bis eyes from it and look at himself all the while.
Living forms are, by their very definition, forms that are able to live. In whatever way the adaptation of the organism to its circumstances is explained, it has necessv lily been sufficient, since the species has subsisted. In this sense, each of the successive species that paleon- tology and zoology describes was a success carried ofE by life. But we get a very different impression when we refer each species to the movement that has left it behind on its way, instead of to the conditions into which it has been set. Often this movement has turned aside; very often, too, it has stopped short ; what was to have been a thoroughfare has become a terminus. From this new point of \-iew, failure seems the rule, success exceptional and always imperfect. We shall see that, of the four main directions along which animal life bent its course, two have led to blind alleys, and, in the other two, the effort has generally been out of proportion to the result.
Documents are lacking to reconstruct this history in
detail, but we can make out its main Unes. We have
Already sud that animals and vegetables must have
130 Creative Evolution
separated soon from their common stock, the vegetable falling asleep in immobility, the animal, on the con- trary, becoming more and more awake and marching on to the conquest of a nervous system. Probably the effort of the animal kingdom resulted in creating oi^anisms still very simple, but endowed with a certain freedom of action, and, above all, with a shape so undecided that it could lend itself to any future determination. These animals may have resembled some of our worms, but with this difference, however, that the worms living to- day, to which they could be compared, are but the empty and fixed examples of infinitely plastic forms, pregnant with an unlimited future, the common stock of the echino- denns, molluscs, arthropods, and vertebrates.
One danger lay in wait for them, one obstacle which
might have stopped the soaring course of animal life.
There is one peculiarity with which we cannot help
being struck when glancing over the fauna ol primitive
times, namely, the imprisonment of the animal in a more
or less solid sheath, which must have obstructed and
often even paralyzed its movements. The molluscs
of that time had a shell more universally than those of
to-day. The arthropods in general were provided with a
carapace; most of them were crustaceans. The more
ancient fishes had a bony sheath of extreme hardness."
The explanation of this general fact should be sought,
we believe, in a tendency of soft organisms to defend
themselves against one another by making themselves,
as far as possible, undevourable. Each species, in the act
by which it comes into being, trends towards that which
is most expedient. Just as among primitive organisms
there were some that turned towards animal life by re-
8e«. on these different points, tbe work of Gaudry, Etaai de jiaUon- MogU philotophique, fans, 1S90, pp. 14-10 and 78-79.