Taking the earth as a whole, and the human race in its entirety, the numbers of mankind, like those of animals, should remain nearly constant throughout time; for they depend upon an equilibrium of physical causes which has long since been reached, and which neither man's moral nor his physical efforts can disturb, inasmuch as these moral efforts do but spring from physical causes, of which they are the special effects. No matter what care man may take of his own species, he can only make it more abundant in one place by destroying it or diminishing its numbers in another. When one part of the globe is overpeopled, men emigrate, spread themselves over other countries, destroy one another, and establish laws and customs which sometimes only too surely prevent excess of population. In those climates where fecundity is greatest, as in China, Egypt, and Guinea, they banish, mutilate, sell, or drown infants. Here, we condemn them to a perpetual celibacy. Those who are in being find it easy to assert rights over the unborn. Regarding themselves as the necessary, they annihilate the contingent, and suppress future generations for their own pleasure and advantage. Man does for his own race, without perceiving it, what he does also for the inferior animals: that is to say, he protects it and encourages it to increase, or neglects it according to his sense of needaccording as advantage or inconvenience is expected as the consequence of either course. And since all these moral effects themselves depend upon physical causes, which have been in permanent equilibrium ever since the world was formed, it follows that the numbers of

mankind, like those of animals, should remain constant.

"Nevertheless, this fixed state, this constant number, is not absolute, all physical and moral causes, and all the results which spring from them, balance themselves, as though, upon a see-saw, which has a certain play, but never so much as that equilibrium should be altogether lost. As everything in the universe is in movement, and as all the forces which are contained in matter act one against the other and counterbalance one another, all is done by a kind of oscillation; of which the mean points are those to which we refer as being the ordinary course of nature, while the extremes are the periods which deviate from that course most widely. And, as a matter of fact, with animals as much as with plants, a time of unusual fecundity is commonly followed by one of sterility; abundance and dearth come alternately, and often at such short intervals that we may foretell the production of a coming year by our knowledge of the past one. Our apples, pears, oaks, beeches, and the greater number of our fruit and forest trees, bear freely but about one year in two. Caterpillars, cockchafers, woodlice, which in one year may multiply with great abundance, will appear but sparsely in the next. What indeed would become of all the good things of the earth, what would become of the useful animals, and indeed of man himself, if each individual in these years of excess was to leave its quotum of offspring? This, however, does not happen, for destruction and sterility follow closely upon excessive fecundity, and, independently of the contagion which follows inevitably upon

overcrowding, each species has its own special sources of death and destruction, which are of themselves sufficient to compensate for excess in any past generation.

"Nevertheless the foregoing should not be taken in an absolute sense, nor yet too strictly,-especially in the case of those races which are not left entirely to the care of Nature. Those which man takes care of-commencing with his own-are more abundant than they would be without his care, yet, as his power of taking this care is limited, the increase which has taken place is also fixed, and has long been restrained within impassable boundaries. Again, though in civilized countries man, and all the animals useful to him, are more numerous than in other places, yet their numbers never become excessive, for the same power which brings them into being destroys them as soon as they are found inconvenient.” *

The Carnivora-Sensation.

Buffon begins his seventh volume with some remarks on the carnivora in general, which I would gladly quote at fuller length than my space will allow. He dwells on the fact that the number, as well as the fecundity of the insect races is greater than that of the mammalia, and even than of plants; and he points out that "violent death is almost as necessary an usage as is the law that we must all, in one way or another, die." This leads him to the question whether animals can feel. "To speak seriously," (au réel) he says (and why this, if he had *Tom. vi. p. 252, 1756.

always spoken seriously? *), "can we doubt that those animals whose organization resembles our own, feel the same sensations as we do? They must feel, for they have senses, and they must feel more and more in proportion as their senses are more active and more perfect." Those whose organ of any sense is imperfect, have but imperfect perception in respect of that sense; and those that are entirely without the organ want also all corresponding sensation. "Movement is the necessary consequence of acts of perception. I have already shown that in whatever manner a living being is organized, if it has perceptions at all, it cannot fail to show that it has them by some kind of movement of its body. Hence plants, though highly organized, have no feeling, any more than have those animals which, like plants, manifest no power of motion. Among animals there are those which, like the sensitive plant, have but a certain power of movement about their own parts, and which have no power of locomotion; such animals have as yet but little perception. Those, again, which have power of locomotion, but which, like automata, do but a small number of things, and always after the same fashion, can have only small powers of perception, and these limited to a small number of objects. But in the case of man, what automata, indeed, have we not here! How much do not education and the intercommunication of ideas increase our powers and vivacity of perception. What difference can we not see in this respect between civilized and uncivilized races, between the peasant girl, and the woman of the world? And in like manner among

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* Discours sur la Nature des Animaux,' vol. iv. and p. 113 of this vol.

animals, those which live with us have their perceptions increased in range, while those that are wild have but their natural instinct, which is often more certain but always more limited in range than is the intelligence of domesticated animals."

"For perception to exist in its fullest development in any animal body, that body must form a whole—an ensemble, which shall not only be capable of feeling in all its parts, but shall be so arranged that all these feeling parts shall have a close correspondence with one another, and that no one of them can be disturbed without communicating a portion of that disturbance to every other part. There must also be a single chief centre, with which all these different disturbances may be connected, and from which, as from a common point d'appui, the reactions against them may take their rise. Hence man, and those animals whose organization most resembles man's, will be the most capable of perceptions, while those whose unity is less complete, whose parts have a less close correspondence with each other— which have several centres of sensation, and which seem, in consequence, less to envelope a single existence in a single body than to contain many centres of existence separated and different from one another-these will have fewer, and duller perceptions. The polypus, which can be reproduced by fission; the wasp, whose head even after separation from the body still moves, lives, acts, and even eats as heretofore; the lizard which we deprive neither of sensation nor movement by cutting

* Tom. vii. p. 9, 1758.