The World's Greatest Books - Volume 15 Part 15

(2) That every change in their wants necessitates new actions to supply them, and consequently new habits.

(3) That every new want calling for new actions for its satisfaction affects the animal in one of two ways. Either it has to make more frequent use of some particular member, and this will develop the part and cause it to increase in size; or it must employ new members which will grow in the animal insensibly in response to the inward yearning to satisfy these wants. And this I will presently prove from known facts.

How the new wants have been able to attain satisfaction, and how the new habits have been acquired, it will be easy to see if regard be had to the two following laws, which observation has always confirmed.

FIRST LAW.--In every animal which has not arrived at the term of its developments, the more frequent and sustained use of any organ strengthens, develops, and enlarges that organ, and gives it a power commensurate with the duration of this employment of it. On the other hand, constant disuse of such organ weakens it by degrees, causes it to deteriorate, and progressively diminishes its faculties, so that in the end it disappears.

SECOND LAW.--All qualities naturally acquired by individuals as the result of circ.u.mstances to which their race is exposed for a considerable time, or as a consequence of a predominant employment or the disuse of a certain organ, nature preserves to individual offspring; provided that the acquired modifications are common to the two s.e.xes, or, at least, to both parents of the individual offspring.

Naturalists have observed that the members of animals are adapted to their use, and thence have concluded hitherto that the formation of the members has led to their appropriate employment. Now, this is an error.

For observation plainly shows that, on the contrary, the development of the members has been caused by their need and use; that these have caused them to come into existence where they were wanting.

But let us examine the facts which bear upon the effects of employment or disuse of organs resulting from the habits which a race has been compelled to form.

_II.--The Penalties of Disuse_

Permanent disuse of an organ as a consequence of acquired habits gradually impoverishes it, and in the end causes it to disappear, or even annihilates it altogether.

Thus vertebrates, which, in spite of innumerable particular distinctions, are alike in the plan of their organisation, are generally armed with teeth. Yet those of them which by circ.u.mstances have acquired the habit of swallowing their prey without mastication have been liable to leave their teeth undeveloped. Consequently, the teeth have either remained hidden between the bony plates of the jaws, or have even been, in the course of time, annihilated.

The whale was supposed to have no teeth at all till M. Geoffrey found them hidden in the jaws of the foetus. He has also found in birds the groove in which teeth might be placed, but without any trace of the teeth themselves. A similar case to that of the whale is the ant-eater (_nyomecophaga_), which has long given up the practice of mastication.

Eyes in the head are an essential part of the organisation of vertebrates. Yet the mole, which habitually makes no use of the sense of sight, has eyes so small that they can hardly be seen; and the aspalax, whose habits-resemble a mole's, has totally lost its sight, and shows but vestiges of eyes. So also the proteus, which inhabits dark caves under water.

In such cases, since the animals in question belong to a type of which eyes are an essential part, it is clear that the impoverishment, and even the total disappearance, of these organs are the results of long continued disuse.

With hearing, the case is otherwise. Sound traverses everything.

Therefore, wherever an animal dwells it may exercise this faculty. And so no vertebrate lacks it, and we never find it re-appearing in any of the lower ranges. Sight disappears, re-appears, and disappears again, according as circ.u.mstances deny or permit its exercise.

Four legs attached to its skeleton are part of the reptile type; and serpents, particularly as between them and the fishes come the batrachians--frogs, etc.--ought to have four legs.

But serpents, having acquired the habit of gliding along the ground, and concealing themselves amid the gra.s.s, their bodies, as a consequence of constantly repeated efforts to lengthen themselves out in order to pa.s.s through narrow pa.s.sages, have acquired considerable length of body which is out of all proportion to their breadth.

Now, feet would have been useless to these animals, and consequently would have remained unemployed; for long legs would have interfered with their desire to go on their bellies; and short legs, being limited in number to four, would have been incapable of moving their bodies. Thus total disuse among these races of animals has caused the parts which have fallen into disuse totally to disappear.

Many insects, which by their order and genus should have wings, lack them more or less completely for similar reasons.

_III.--The Advantages of Use_

The frequent use of an organ, if constant and habitual, increases its powers, develops it, and makes it acquire dimensions and potency such as are not found among animals which use it less.

Of this principle, the web-feet of some birds, the long legs and neck of the stork, are examples. Similarly, the elongated tongue of the ant-eater, and those of lizards and serpents.

Such wants, and the sustained efforts to satisfy them, have also resulted in the displacement of organs. Fishes which swim habitually in great ma.s.ses of water, since they need to see right and left of them, have the eyes one upon either side of the head. Their bodies, more or less flat, according to species, have their edges perpendicular to the plane of the water; and their eyes are so placed as to be one on either side of the flattened body. But those whose habits bring them constantly to the banks, especially sloping banks, have been obliged to lie over upon the flattened surface in order to approach more nearly. In this position, in which more light falls on the upper than on the under surface, and their attention is more particularly fixed upon what is going on above than on what is going on below them, this want has forced one of the eyes to undergo a kind of displacement, and to keep the strange position which it occupies in the head of a sole or a turbot.

The situation is not symmetrical because the mutation is not complete.

In the case of the skate, however, it is complete; for in these fish the transverse flattening of the body is quite horizontal, no less than that of the head. And so the eyes of a skate are not only placed both of them on the upper surface, but have become symmetrical.

Serpents need princ.i.p.ally to see things above them, and, in response to this need, the eyes are placed so high up at the sides of the head that they can see easily what is above them on either side, while they can see in front of them but a very little distance. To compensate for this, the tongue, with which they test bodies in their line of march, has been rendered by this habit thin, long, and very contractile, and even, in most species, has been split so as to be able to test more than one object at a time. The same custom has resulted similarly in the formation of an opening at the end of the muzzle by which the tongue may be protruded without any necessity for the opening of the jaws.

The effect of use is curiously ill.u.s.trated in the form and figure of the giraffe. This animal, the largest of mammals, is found in the interior of Africa, where the ground is scorched and dest.i.tute of gra.s.s, and has to browse on the foliage of trees. From the continual stretching thus necessitated over a great s.p.a.ce of time in all the individuals of the race, it has resulted that the fore legs have become longer than the hind legs, and that the neck has become so elongated that the giraffe, without standing on its hind legs, can raise its head to a height of nearly twenty feet. Observation of all animals will furnish similar examples.

None, perhaps, is more striking than that of the kangaroo. This animal, which carries its young in an abdominal pouch, has acquired the habit of carrying itself upright upon its hind legs and tail, and of moving from place to place in a series of leaps, during which, in order not to hurt its little ones, it preserves its upright posture. Observe the result.

(1) Its front limbs, which it uses very little, resting on them only in the instant during which it quits its erect posture, have never acquired a development in proportion to the other parts; they have remained thin, little, and weak.

(2) The hind legs, almost continually in action, whether to bear the weight of the whole body or to execute its leaps, have, on the contrary, obtained a considerable development; they are very big and very strong.

(3) Finally, the tail, which we observe to be actively employed, both to support the animal's weight and to execute its princ.i.p.al movements, has acquired at its base a thickness and a strength that are extremely remarkable.

When the will determines an animal to a certain action, the organs concerned are forthwith stimulated by a flow of subtle fluids, which are the determining cause of organic changes and developments. And multiplied repet.i.tions of such acts strengthen, extend, and even call into being the organs necessary to them. Now, every change in an organ which has been acquired by habitual use sufficient to originate it is reproduced in the offspring if it is common to both the individuals which have come together for the reproduction of their species. In the end, this change is propagated and pa.s.ses to all the individuals which come after and are submitted to the same conditions, without its being necessary that they should acquire it in the original manner.

For the rest, in the union of disparate couples, the disparity is necessarily opposed to the constant propagation of such qualities and outward forms. This is why man, who is exposed to such diversity of conditions, does not preserve and propagate the qualities or the accidental defects which he has been in the way of acquiring. Such peculiarities will be produced only in case two individuals who share them unite; these will produce offspring bearing similar characteristics, and, if successive generations restrict themselves to similar unions, a distinct race will then be formed. But perpetual intermixture will cause all characters acquired through particular circ.u.mstances to disappear. If it were not for the distances which separate the races of men, such intermixture would quickly obliterate all national distinctions.

_IV.--The Conclusion_

Here, then, is the conclusion to which we have come. It is a fact that every genus and species of animal has its characteristic habits combined with an organisation perfectly in harmony with them. From the consideration of this fact one of two conclusions must follow, and that though neither of them can be proved.

(1) The conclusion admitted hitherto--that nature (or its Author) in creating the animals has foreseen all the possible sets of circ.u.mstances in which they would have to live, has given to each species a constant organisation, and has shaped its parts in a determined and invariable way so that every species is compelled to live in the districts and the climates where it is actually formed, and to keep the habits by which it is actually known.

(2) My own conclusion--that nature has produced in succession all the animal species, beginning with the more imperfect, or the simpler, and ending with the more perfect; that in so doing it has gradually complicated their organisation; and that of these animals, dispersed over the habitable globe, every species has acquired, under the influence of the circ.u.mstances amid which it is found, the habits and modifications of form which we a.s.sociate with it.

To prove that the second of these hypotheses is unfounded, it will be necessary, first, to prove that the surface of the globe never varies in character, in exposure, situation, whether elevated or sheltered, climate, etc.; and, secondly, to prove that no part of the animal world undergoes, even in the course of long periods of time, any modification through change of circ.u.mstances, or as a consequence of a changed manner of life and action.

Now, a single fact which establishes that an animal, after a long period of domestication, differs from the wild stock from which it derives, and that among the various domesticated members of a species may be found differences no less marked between individuals which, have been subjected to one use and those which have been subjected to another, makes it certain that the former conclusion is not consistent with the laws of nature, and that the second is.

Everything, therefore, concurs to prove my a.s.sertion, to wit--that it is not form, whether of the body or of the parts, which gives rise to the habits of animals and their manner of life; but that, on the contrary, in the habits, the manner of living, and all the other circ.u.mstances of environment, we have those things which in the course of time have built up animal bodies with all their members. With new forms new faculties have been acquired, and little by little nature has come to shape animals and all living things in their present forms.

JOHANN LAVATER

Physiognomical Fragments

Johann Caspar Lavater, the Swiss theologian, poet, and physiognomist, was born at Zurich on November 15, 1741. He began his public life at the age of twenty-one as a political reformer.

Five years later he appeared as a poet, and published a volume of poetry which was very favourably received. During the next five years he produced a religious work, which was considered heretical, although its mystic, religious enthusiasm appealed to a considerable audience. His fame, however, rests neither on his poetry nor on his theology, but on his physiognomical studies, published in four volumes between 1775-78 under the t.i.tle "Physiognomical Fragments for the Advancement of Human Knowledge and Human Life" ("Physiognomische Fragmente zur Beforderung des Menschenkenntniss und Menschenliebe"). The book is diffuse and inconsequent, but it contains many shrewd observations with respect to physiognomy and has had no little influence on popular opinion in this matter. Lavater died on January 2, 1801.

_I.--The Truth of Physiognomy_

There can be no doubt of the truth of physiognomy. All countenances, all forms, all created beings, are not only different from each other in their cla.s.ses, races, kinds, but are also individually distinct. It is indisputable that all men estimate all things whatever by their external temporary superficies--that is to say, by their physiognomy. Is not all nature physiognomy, superficies and contents, body and spirit, external effect and internal power? There is not a man who does not judge of all things that pa.s.s through his hands by their physiognomy--there is not a man who does not more or less, the first time he is in company with a stranger, observe, estimate, compare, judge him according to appearances. When each apple, each apricot, has a physiognomy peculiar to itself, shall man, the lord of the earth, have none?

Man is the most perfect of all earthly creatures. In no other creature are so wonderfully united the animal, the intellectual, and the moral.

And man's organisation peculiarly distinguishes him from all other beings, and shows him to be infinitely superior to all those other visible organisms by which he is surrounded. His head, especially his face, convinces the accurate observer, who is capable of investigating truth, of the greatness and superiority of his intellectual qualities.

The eye, the expression, the cheeks, the mouth, the forehead, whether considered in a state of entire rest, or during their innumerable varieties of motion--in fine, whatever is understood by physiognomy--are the most expressive, the most convincing picture of interior sensations, desires, pa.s.sions, will, and of all those properties which so much exalt moral above animal life.