Nature achieves through step by step

Nature achieves nothing except step by step.

An enormous length of time and considerable variation in the sequence of circumstances for nature to lead the organic structure of animals to the complexity and development that we see in those who are the most improved.

The varied and numerous strata making up the exterior crust of the earth proves its great age.

The very slow but continuous displacement of the sea basin (1) confirms the prodigious antiquity of the terrestrial globe.

then a consideration of the degree of improvement which the organic structures of most animals must have reached helps, in its turn, to provide the highest quality evidence of this truth.

To establish firmly the basis of this new proof, it will be necessary first to bring fully to light the proof relevant to the progress in organic structures themselves.

It will be necessary to:

• ascertain the reality of this progress
• collect the best established facts in this matter
• indicate the means which nature possesses to give to all its productions the existence which they enjoy.

Let us note, meanwhile, that although it is generally acceptable, in referring to the beings which make up each kingdom, to indicate them under the general term productions of nature, it nevertheless appears that people have no clear idea associated with this expression.

It seems that the prejudice against a particular origin prevents us from recognizing that nature possesses the ability and all the means to bring to life so many different beings on her own, continually to vary, although very slowly, the races of those which enjoy life, and to maintain throughout the general order which we observe.

In order to be able to include, in our thinking, all existing animals and to place these animals in a perspective easy to grasp, it is appropriate to recall that all the natural productions which we can observe have been divided up by naturalists, for a long time now, into three kingdoms, under the denominations animal kingdom, vegetable kingdom, and mineral kingdom. By this division, the entities comprising each of these kingdoms have been set up comparatively, as if on the same line, although some have an origin very different from others.

I have found it more convenient to use another primary division.

I separate all the natural productions comprising the 3 kingdoms into 2 main branches:

1. Organically structured bodies which are alive

Living bodies, like the animals and plants, are part of this.

2. Raw bodies without life.

But what people do not so readily know, because prevailing hypotheses do not allow them to believe it, is that living bodies, as a result of their organic action and faculties, as well as the mutations which bring about in them organic movements, form themselves their own substance and secretory material (Hydrogéologie, p. 112).

What people understand even less is that through their remains these living bodies give rise to the existence of all the composite materials, raw or inorganic, which we observe in nature.

The various types of this material multiply in nature over time according to the circumstances of their location, through changes which they undergo imperceptibly and which simplify them more and more and lead, after a great deal of time, to the complete separation of the main elements composing them.

These are the various raw non-living materials, solid or liquid, which comprise the second branch of the productions of nature and which, for the most part, are known under the name minerals.

Between raw materials and living bodies, there is an immense hiatus which does not allow us to rank on the same line these two sorts of bodies, nor to undertake to link them by any modification, something which has been attempted but in vain.

All the known living bodies divide themselves neatly into two particular kingdoms, based on essential differences which distinguish animals from plants. In spite of what people have said about this, I am convinced that there is no longer a real point of subtle melding between these two kingdoms and that, consequently, that there are no animal-plants (something expressed in the word zoophyte) nor plant-animals.

The irritability in all or in certain parts is the most general characteristic of animals. That is more common than the faculty of voluntary movements and of feeling, more even that that of guiding oneself. Now, all the plants, without omitting even the plants called sensitive, nor those which move certain of their parts at the first touch or at the first contact with air, completely lack irritability. I have observed this point elsewhere.

We know that irritability is a faculty essential to the parts or some of them in animals. The actions of irritability are never suspended or destroyed so long as the animal is alive and the irritable part has not suffered any lesion in its organic structure. The effect of irritability consists of a contraction which the entire irritable part undergoes instantaneously on contact with a foreign body. The contraction stops with the cause and comes again, after the relaxation of the part, when new contacts happen to irritate it. Now, nothing like this has ever been observed in any part of plants.

When I touch the extended branches of a sensitive (mimosa pudica), instead of a contraction, I observe immediately in the attachments of the branches and disturbed petioles, a relaxation which allows these branches and petioles of the leaves to collapse, something which makes even the leaflets in this case droop down on one another. Once this drooping occurs, it is a waste of time to touch the branches and the leaves of the plant again; the effect does not recur. A relatively long time is needed, unless it is very hot, for the cause which can swell the articulations of the small branches and the leaves of the sensitive to raise again and extend all its parts and to deal with the sagging in such a way that it can happen again through contact or a light tremor.

I do not recognize in this phenomenon any connection with irritability in animals. But I do know that with plants during periods of growth, above all when it is hot, a great deal of elastic fluid is created, some of which is exhaled constantly. Thus I have concluded that in leguminous plants, these elastic fluids can gather particularly in the articulations of the leaves before dissipating and that they can there strain these joints and extend out the leaves or leaflets.

In such a case, the slow dissipation of the elastic fluids we are talking about, stimulated in the legumes by the arrival of night or the sudden dissipation of the same fluids stimulated in the mimosa pudica by a small tremor gives rise, in the legumes generally, to the phenomenon known by the term plant sleep and in the sensitive to what people attribute incorrectly to irritability (2).

Since, as a consequence of observations which I reveal further on and the conclusions I have drawn from them, it is not generally true that animals are feeling beings, all endowed, without exception, with the power of making voluntary acts and, consequently, having the option of moving at their own will, the definition which has been given of animals up to the present to distinguish them from plants is totally inappropriate. Thus I have already proposed to substitute for it the following, on the ground that it conforms more closely to the truth and is more appropriate for characterizing the beings which constitute both kingdoms of living bodies.