2. EXAMINATION DU LIVRE DE M. DARWIN SUR L'ORIGINE DES ESPECES. PAR P. FLOURENS. Paris, 1864.
In the course of the present year  several foreign commentaries upon Mr. Darwin's great work have made their appearance. Those who have perused that remarkable chapter of the "Antiquity of Man," in which Sir Charles Lyell draws a parallel between the development of species and that of languages, will be glad to hear that one of the most eminent philologers of Germany, Professor Schleicher, has, independently, published a most instructive and philosophical pamphlet (an excellent notice of which is to be found in the Reader, for February 27th of this year) supporting similar views with all the weight of his special knowledge and established authority as a linguist. Professor Haeckel, to whom Schleicher addresses himself, previously took occasion, in his splendid monograph on the Radiolaria, to express his high appreciation of, and general concordance with, Mr. Darwin's views.
But the most elaborate criticisms of the "Origin of Species" which have appeared are two works of very widely different merit, the one by Professor Koelliker, the well-known anatomist and histologist of Wuerzburg; the other by M. Flourens, Perpetual Secretary of the French Academy of Sciences.
Professor Koelliker's critical essay "Upon the Darwinian Theory" is, like all that proceeds from the pen of that thoughtful and accomplished writer, worthy of the most careful consideration. It comprises a brief but clear sketch of Darwin's views, followed by an enumeration of the leading difficulties in the way of their acceptance; difficulties which would appear to be insurmountable to Professor Koelliker, inasmuch as he proposes to replace Mr. Darwin's Theory by one which he terms the "Theory of Heterogeneous Generation." We shall proceed to consider first the destructive, and secondly, the constructive portion of the essay.
We regret to find ourselves compelled to dissent very widely from many of Professor Koelliker's remarks; and from none more thoroughly than from those in which he seeks to define what we may term the philosophical position of Darwinism.
"Darwin," says Professor Koelliker, "is, in the fullest sense of the Word, a Teleologist. He says quite distinctly (First Edition, pp.199, 200) that every particular in the structure of an animal has been created for its benefit, and he regards the whole series of animal forms only from this point of view."
"7. The teleological general conception adopted by Darwin is a mistaken one.
"Varieties arise irrespectively of the notion of purpose, or of utility, according to general laws of Nature, and may be either useful, or hurtful, or indifferent.
"The assumption that an organism exists only on account of some definite end in view, and represents something more than the incorporation of a general idea, or law, implies a one-sided conception of the universe. Assuredly, every organ has, and every organism fulfils, its end, but its purpose is not the condition of its existence. Every organism is also sufficiently perfect for the purpose it serves, and in that, at least, it is useless to seek for a cause of its improvement."
It is singular how differently one and the same book will impress different minds. That which struck the present writer most forcibly on his first perusal of the "Origin of Species" was the conviction that Teleology, as commonly understood, had received its deathblow at Mr. Darwin's hands. For the teleological argument runs thus: an organ or organism (A) is precisely fitted to perform a function or purpose (B); therefore it was specially constructed to perform that function. In Paley's famous illustration, the adaptation of all the parts of the watch to the function, or purpose, of showing the time, is held to be evidence that the watch was specially contrived to that end; on the ground, that the only cause we know of, competent to produce such an effect as a watch which shall keep time, is a contriving intelligence adapting the means directly to that end.
Suppose, however, that any one had been able to show that the watch had not been made directly by any person, but that it was the result of the modification of another watch which kept time but poorly; and that this again had proceeded from a structure which could hardly be called a watch at all -- seeing that it had no figures on the dial and the hands were rudimentary; and that going back and back in time we came at last to a revolving barrel as the earliest traceable rudiment of the whole fabric. And imagine that it had been possible to show that all these changes had resulted, first, from a tendency of the structure to vary indefinitely; and secondly, from something in the surrounding world which helped all variations in the direction of an accurate time-keeper, and checked all those in other directions; then it is obvious that the force of Paley's argument would be gone. For it would be demonstrated that an apparatus thoroughly well adapted to a particular purpose might be the result of a method of trial and error worked by unintelligent agents, as well as of the direct application of the means appropriate to that end, by an intelligent agent.
Now it appears to us that what we have here, for illustration's sake, supposed to be done with the watch, is exactly what the establishment of Darwin's Theory will do for the organic world. For the notion that every organism has been created as it is and launched straight at a purpose, Mr. Darwin substitutes the conception of something which may fairly be termed a method of trial and error. Organisms vary incessantly; of these variations the few meet with surrounding conditions which suit them and thrive; the many are unsuited and become extinguished.
According to Teleology, each organism is like a rifle bullet fired straight at a mark; according to Darwin, organisms are like grapeshot of which one hits something and the rest fall wide.
For the teleologist an organism exists because it was made for the conditions in which it is found; for the Darwinian an organism exists because, out of many of its kind, it is the only one which has been able to persist in the conditions in which it is found.
Teleology implies that the organs of every organism are perfect and cannot be improved; the Darwinian theory simply affirms that they work well enough to enable the organism to hold its own against such competitors as it has met with, but admits the possibility of indefinite improvement. But an example may bring into clearer light the profound opposition between the ordinary teleological, and the Darwinian, conception.
Cats catch mice, small birds and the like, very well. Teleology tells us that they do so because they were expressly constructed for so doing -- that they are perfect mousing apparatuses, so perfect and so delicately adjusted that no one of their organs could be altered, without the change involving the alteration of all the rest. Darwinism affirms, on the contrary, that there was no express construction concerned in the matter; but that among the multitudinous variations of the Feline stock, many of which died out from want of power to resist opposing influences, some, the cats, were better fitted to catch mice than others, whence they throve and persisted, in proportion to the advantage over their fellows thus offered to them.
Far from imagining that cats exist in order to catch mice well, Darwinism supposes that cats exist because they catch mice well -- mousing being not the end, but the condition, of their existence. And if the cat-type has long persisted as we know it, the interpretation of the fact upon Darwinian principles would be, not that the cats have remained invariable, but that such varieties as have incessantly occurred have been, on the whole, less fitted to get on in the world than the existing stock.
If we apprehend the spirit of the "Origin of Species" rightly, then, nothing can be more entirely and absolutely opposed to Teleology, as it is commonly understood, than the Darwinian Theory. So far from being a "Teleologist in the fullest sense of the word," we should deny that he is a Teleologist in the ordinary sense at all; and we should say that, apart from his merits as a naturalist, he has rendered a most remarkable service to philosophical thought by enabling the student of Nature to recognise, to their fullest extent, those adaptations to purpose which are so striking in the organic world, and which Teleology has done good service in keeping before our minds, without being false to the fundamental principles of a scientific conception of the universe. The apparently diverging teachings of the Teleologist and of the Morphologist are reconciled by the Darwinian hypothesis.
But leaving our own impressions of the "Origin of Species," and turning to those passages specially cited by Professor Koelliker, we cannot admit that they bear the interpretation he puts upon them. Darwin, if we read him rightly, does not affirm that every detail in the structure of an animal has been created for its benefit. His words are (p.199): --
"The foregoing remarks lead me to say a few words on the protest lately made by some naturalists against the utilitarian doctrine that every detail of structure has been produced for the good of its possessor. They believe that very many structures have been created for beauty in the eyes of man, or for mere variety. This doctrine, if true, would be absolutely fatal to my theory -- yet I fully admit that many structures are of no direct use to their possessor."
And after sundry illustrations and qualifications, he concludes (p.200): --
"Hence every detail of structure in every living creature (making some little allowance for the direct action of physical conditions) may be viewed either as having been of special use to some ancestral form, or as being now of special use to the descendants of this form -- either directly, or indirectly, through the complex laws of growth."
But it is one thing to say, Darwinically, that every detail observed in an animal's structure is of use to it, or has been of use to its ancestors; and quite another to affirm, teleologically, that every detail of an animal's structure has been created for its benefit. On the former hypothesis, for example, the teeth of the foetal Balaena have a meaning; on the latter, none. So far as we are aware, there is not a phrase in the "Origin of Species," inconsistent with Professor Koelliker's position, that "varieties arise irrespectively of the notion of purpose, or of utility, according to general laws of Nature, and may be either useful, or hurtful, or indifferent."
On the contrary, Mr. Darwin writes (Summary of Chap. V.): --
"Our ignorance of the laws of variation is profound. Not in one case out of a hundred can we pretend to assign any reason why this or that part varies more or less from the same part in the parents.... The external conditions of life, as climate and food, &c. seem to have induced some slight modifications. Habit, in producing constitutional differences, and use, in strengthening, and disuse, in weakening and diminishing organs, seem to have been more potent in their effects."
And finally, as if to prevent all possible misconception, Mr. Darwin concludes his Chapter on Variation with these pregnant words: --
"Whatever the cause may be of each slight difference in the offspring from their parents -- and a cause for each must exist -- it is the steady accumulation, through natural selection of such differences, when beneficial to the individual, that gives rise to all the more important modifications of structure, by which the innumerable beings on the face of the earth are enabled to struggle with each other, and the best adapted to survive."
We have dwelt at length upon this subject, because of its great general importance, and because we believe that Professor Koelliker's criticisms on this head are based upon a misapprehension of Mr. Darwin's views -- substantially they appear to us to coincide with his own. The other objections which Professor Koelliker enumerates and discusses are the following: --
"1. No transitional forms between existing species are known; and known varieties, whether selected or spontaneous, never go so far as to establish new species."
To this Professor Koelliker appears to attach some weight. He makes the suggestion that the short-faced tumbler pigeon may be a pathological product.
"2. No transitional forms of animals are met with among the organic remains of earlier epochs."
Upon this, Professor Koelliker remarks that the absence of transitional forms in the fossil world, though not necessarily fatal to Darwin's views, weakens his case.
"3. The struggle for existence does not take place."
To this objection, urged by Pelzeln, Koelliker, very justly, attaches no weight.
"4. A tendency of organisms to give rise to useful varieties, and a natural selection, do not exist.
"The varieties which are found arise in consequence of manifold external influences, and it is not obvious why they all, or partially, should be particularly useful. Each animal suffices for its own ends, is perfect of its kind, and needs no further development. Should, however, a variety be useful and even maintain itself, there is no obvious reason why it should change any further. The whole conception of the imperfection of organisms and the necessity of their becoming perfected is plainly the weakest side of Darwin's Theory, and a pis aller (Nothbehelf) because Darwin could think of no other principle by which to explain the metamorphoses which, as I also believe, have occurred."
Here again we must venture to dissent completely from Professor Koelliker's conception of Mr. Darwin's hypothesis. It appears to us to be one of the many peculiar merits of that hypothesis that it involves no belief in a necessary and continual progress of organisms.
Again, Mr. Darwin, if we read him aright, assumes no special tendency of organisms to give rise to useful varieties, and knows nothing of needs of development, or necessity of perfection. What he says is, in substance: All organisms vary. It is in the highest degree improbable that any given variety should have exactly the same relations to surrounding conditions as the parent stock. In that case it is either better fitted (when the variation may be called useful), or worse fitted, to cope with them. If better, it will tend to supplant the parent stock; if worse, it will tend to be extinguished by the parent stock.
If (as is hardly conceivable) the new variety is so perfectly adapted to the conditions that no improvement upon it is possible, -- it will persist, because, though it does not cease to vary, the varieties will be inferior to itself.
If, as is more probable, the new variety is by no means perfectly adapted to its conditions, but only fairly well adapted to them, it will persist, so long as none of the varieties which it throws off are better adapted than itself.
On the other hand, as soon as it varies in a useful way, i.e. when the variation is such as to adapt it more perfectly to its conditions, the fresh variety will tend to supplant the former.
So far from a gradual progress towards perfection forming any necessary part of the Darwinian creed, it appears to us that it is perfectly consistent with indefinite persistence in one state, or with a gradual retrogression. Suppose, for example, a return of the glacial epoch and a spread of polar climatal conditions over the whole globe. The operation of natural selection under these circumstances would tend, on the whole, to the weeding out of the higher organisms and the cherishing of the lower forms of life. Cryptogamic vegetation would have the advantage over Phanerogamic; Hydrozoa over Corals; Crustacea over Insecta, and Amphipoda and Isopoda over the higher Crustacea; Cetaceans and Seals over the Primates; the civilization of the Esquimaux over that of the European.
"5. Pelzeln has also objected that if the later organisms have proceeded from the earlier, the whole developmental series, from the simplest to the highest, could not now exist; in such a case the simpler organisms must have disappeared."
To this Professor Koelliker replies, with perfect justice, that the conclusion drawn by Pelzeln does not really follow from Darwin's premises, and that, if we take the facts of Palaeontology as they stand, they rather support than oppose Darwin's theory.
"6. Great weight must be attached to the objection brought forward by Huxley, otherwise a warm supporter of Darwin's hypothesis, that we know of no varieties which are sterile with one another, as is the rule among sharply distinguished animal forms.
"If Darwin is right, it must be demonstrated that forms may be produced by selection, which, like the present sharply distinguished animal forms, are infertile when coupled with one another, and this has not been done."
The weight of this objection is obvious; but our ignorance of the conditions of fertility and sterility, the want of carefully conducted experiments extending over long series of years, and the strange anomalies presented by the results of the cross-fertilization of many plants, should all, as Mr. Darwin has urged, be taken into account in considering it.
The seventh objection is that we have already discussed (supra, p.329).
The eighth and last stands as follows: --
"8. The developmental theory of Darwin is not needed to enable us to understand the regular harmonious progress of the complete series of organic forms from the simpler to the more perfect.
"The existence of general laws of Nature explains this harmony, even if we assume that all beings have arisen separately and independent of one another. Darwin forgets that inorganic nature, in which there can be no thought of a genetic connexion of forms, exhibits the same regular plan, the same harmony, as the organic world; and that, to cite only one example, there is as much a natural system of minerals as of plants and animals."
We do not feel quite sure that we seize Professor Koelliker's meaning here, but he appears to suggest that the observation of the general order and harmony which pervade inorganic nature, would lead us to anticipate a similar order and harmony in the organic world. And this is no doubt true, but it by no means follows that the particular order and harmony observed among them should be that which we see. Surely the stripes of dun horses, and the teeth of the foetal Balaena, are not explained by the "existence of general laws of Nature." Mr. Darwin endeavours to explain the exact order of organic nature which exists; not the mere fact that there is some order.
And with regard to the existence of a natural system of minerals; the obvious reply is that there may be a natural classification of any objects -- of stones on a sea-beach, or of works of art; a natural classification being simply an assemblage of objects in groups, so as to express their most important and fundamental resemblances and differences. No doubt Mr. Darwin believes that those resemblances and differences upon which our natural systems or classifications of animals and plants are based, are resemblances and differences which have been produced genetically, but we can discover no reason for supposing that he denies the existence of natural classifications of other kinds.
And, after all, is it quite so certain that a genetic relation may not underlie the classification of minerals? The inorganic world has not always been what we see it. It has certainly had its metamorphoses, and, very probably, a long "Entwickelungsgeschichte" out of a nebular blastema. Who knows how far that amount of likeness among sets of minerals, in virtue of which they are now grouped into families and orders, may not be the expression of the common conditions to which that particular patch of nebulous fog, which may have been constituted by their atoms, and of which they may be, in the strictest sense, the descendants, was subjected?
It will be obvious from what has preceded, that we do not agree with Professor Koelliker in thinking the objections which he brings forward so weighty as to be fatal to Darwin's view. But even if the case were otherwise, we should be unable to accept the "Theory of Heterogeneous Generation" which is offered as a substitute. That theory is thus stated: --
"The fundamental conception of this hypothesis is, that, under the influence of a general law of development, the germs of organisms produce others different from themselves. This might happen (1) by the fecundated ova passing, in the course of their development, under particular circumstances, into higher forms; (2) by the primitive and later organisms producing other organisms without fecundation, out of germs or eggs (Parthenogenesis)."
In favour of this hypothesis, Professor Koelliker adduces the well-known facts of Agamogenesis, or "alternate generation;" the extreme dissimilarity of the males and females of many animals; and of the males, females, and neuters of those insects which live in colonies: and he defines its relations to the Darwinian theory as follows: --
"It is obvious that my hypothesis is apparently very similar to Darwin's, inasmuch as I also consider that the various forms of animals have proceeded directly from one another. My hypothesis of the creation of organisms by heterogeneous generation, however, is distinguished very essentially from Darwin's by the entire absence of the principle of useful variations and their natural selection; and my fundamental conception is this, that a great plan of development lies at the foundation of the origin of the whole organic world, impelling the simpler forms to more and more complex developments. How this law operates, what influences determine the development of the eggs and germs, and impel them to assume constantly new forms, I naturally cannot pretend to say; but I can at least adduce the great analogy of the alternation of generations. If a Bipinnaria, a Brachialaria, a Pluteus, is competent to produce the Echinoderm, which is so widely different from it; if a hydroid polype can produce the higher Medusa; if the vermiform Trematode 'nurse' can develop within itself the very unlike Cercaria, it will not appear impossible that the egg, or ciliated embryo, of a sponge, for once, under special conditions, might become a hydroid polype, or the embryo of a Medusa, an Echinoderm."
It is obvious, from these extracts, that Professor Koelliker's hypothesis is based upon the supposed existence of a close analogy between the phaenomena of Agamogenesis and the production of new species from pre-existing ones. But is the analogy a real one? We think that it is not, and, by the hypothesis, cannot be.
For what are the phaenomena of Agamogenesis, stated generally? An impregnated egg develops into an asexual form, A; this gives rise, asexually, to a second form or forms, B, more or less different from A. B may multiply asexually again; in the simpler cases, however, it does not, but, acquiring sexual characters, produces impregnated eggs from whence A once more arises.
No case of Agamogenesis is known in which, when A differs widely from B, it is itself capable of sexual propagation. No case whatever is known in which the progeny of B, by sexual generation, is other than a reproduction of A.
But if this be a true statement of the nature of the process of Agamogenesis, how can it enable us to comprehend the production of new species from already existing ones? Let us suppose Hyaenas to have preceded Dogs, and to have produced the latter in this way. Then the Hyaena will represent A, and the Dog, B. The first difficulty that presents itself is that the Hyaena must be asexual, or the process will be wholly without analogy in the world of Agamogenesis. But passing over this difficulty, and supposing a male and female Dog to be produced at the same time from the Hyaena stock, the progeny of the pair, if the analogy of the simpler kinds of Agamogenesis is to be followed, should be a litter, not of puppies, but of young Hyaenas. For the Agamogenetic series is always, as we have seen, A: B: A: B, &c.; whereas, for the production of a new species, the series must be A: B: B: B, &c. The production of new species, or genera, is the extreme permanent divergence from the primitive stock. All known Agamogenetic processes, on the other hand, end in a complete return to the primitive stock. How then is the production of new species to be rendered intelligible by the analogy of Agamogenesis?
The other alternative put by Professor Koelliker -- the passage of fecundated ova in the course of their development into higher forms -- would, if it occurred, be merely an extreme case of variation in the Darwinian sense, greater in degree than, but perfectly similar in kind to, that which occurred when the well-known Ancon Ram was developed from an ordinary Ewe's ovum. Indeed we have always thought that Mr. Darwin has unnecessarily hampered himself by adhering so strictly to his favourite "Natura non facit saltum." We greatly suspect that she does make considerable jumps in the way of variation now and then, and that these saltations give rise to some of the gaps which appear to exist in the series of known forms.
Strongly and freely as we have ventured to disagree with Professor Koelliker, we have always done so with regret, and we trust without violating that respect which is due, not only to his scientific eminence and to the careful study which he has devoted to the subject, but to the perfect fairness of his argumentation, and the generous appreciation of the worth of Mr. Darwin's labours which he always displays. It would be satisfactory to be able to say as much for M. Flourens.
But the Perpetual Secretary of the French Academy of Sciences deals with Mr. Darwin as the first Napoleon would have treated an "ideologue;" and while displaying a painful weakness of logic and shallowness of information, assumes a tone of authority, which always touches upon the ludicrous, and sometimes passes the limits of good breeding.
For example (p.56): --
"M. Darwin continue: 'Aucune distinction absolue n'a ete et ne peut etre etablie entre les especes et les varietes.' Je vous ai deja dit que vous vous trompiez; une distinction absolue separe les varietes d'avec les especes."
"Je vous ai deja dit; moi, M. le Secretaire perpetuel de l'Academie des Sciences: et vous
'Qui n'etes rien,
what do you mean by asserting the contrary?" Being devoid of the blessings of an Academy in England, we are unaccustomed to see our ablest men treated in this fashion even by a "Perpetual Secretary."
Or again, considering that if there is any one quality of Mr. Darwin's work to which friends and foes have alike borne witness, it is his candour and fairness in admitting and discussing objections, what is to be thought of M. Flourens' assertion, that
"M. Darwin ne cite que les auteurs qui partagent ses opinions." (P.40.)
Once more (p.65):
"Enfin l'ouvrage de M. Darwin a paru. On ne peut qu'etre frappe du talent de l'auteur. Mais que d'idees obscures, que d'idees fausses! Quel jargon metaphysique jete mal a propos dans l'histoire naturelle, qui tombe dans le galimatias des qu'elle sort des idees claires, des idees justes! Quel langage pretentieux et vide! Quelles personifications pueriles et surannees! O lucidite! O solidite de l'esprit Francais, que devenez-vous?"
"Obscure ideas," "metaphysical jargon," "pretentious and empty language," "puerile and superannuated personifications." Mr. Darwin has many and hot opponents on this side of the Channel and in Germany, but we do not recollect to have found precisely these sins in the long catalogue of those hitherto laid to his charge. It is worth while, therefore, to examine into these discoveries effected solely by the aid of the "lucidity and solidity" of the mind of M. Flourens.
According to M. Flourens, Mr. Darwin's great error is that he has personified Nature (p.10), and further that he has
"imagined a natural selection: he imagines afterwards that this power of selecting (pouvoir d'elire) which he gives to Nature is similar to the power of man. These two suppositions admitted, nothing stops him: he plays with Nature as he likes, and makes her do all he pleases." (P.6.)
And this is the way M. Flourens extinguishes natural selection:
"Voyons donc encore une fois, ce qu'il peut y avoir de fonde dans ce qu'on nomme election naturelle.
"L'election naturelle n'est sous un autre nom que la nature. Pour un etre organise, la nature n'est que l'organisation, ni plus ni moins.
"Il faudra donc aussi personnifier l'organisation, et dire que l'organisation choisit l'organisation. L'election naturelle est cette forme substantielle dont on jonait autrefois avec tant de facilite. Aristote disait que 'Si l'art de batir etait dans le bois, cet art agirait comme la nature.' A la place de l'art de batir M. Darwin met l'election naturelle, et c'est tout un: l'un n'est pas plus chimerique que l'autre." (P.31.)
And this is really all that M. Flourens can make of Natural Selection. We have given the original, in fear lest a translation should be regarded as a travesty; but with the original before the reader, we may try to analyse the passage. "For an organized being, Nature is only organization, neither more nor less."
Organized beings then have absolutely no relation to inorganic nature: a plant does not depend on soil or sunshine, climate, depth in the ocean, height above it; the quantity of saline matters in water have no influence upon animal life; the substitution of carbonic acid for oxygen in our atmosphere would hurt nobody! That these are absurdities no one should know better than M. Flourens; but they are logical deductions from the assertion just quoted, and from the further statement that natural selection means only that "organization chooses and selects organization."
For if it be once admitted (what no sane man denies) that the chances of life of any given organism are increased by certain conditions (A) and diminished by their opposites (B), then it is mathematically certain that any change of conditions in the direction of (A) will exercise a selective influence in favour of that organism, tending to its increase and multiplication, while any change in the direction of (B) will exercise a selective influence against that organism, tending to its decrease and extinction.
Or, on the other hand, conditions remaining the same, let a given organism vary (and no one doubts that they do vary) in two directions: into one form (a) better fitted to cope with these conditions than the original stock, and a second (b) less well adapted to them. Then it is no less certain that the conditions in question must exercise a selective influence in favour of (a) and against (b), so that (a) will tend to predominance, and (b) to extirpation.
That M. Flourens should be unable to perceive the logical necessity of these simple arguments, which lie at the foundation of all Mr. Darwin's reasoning; that he should confound an irrefragable deduction from the observed relations of organisms to the conditions which lie around them, with a metaphysical "forme substantielle," or a chimerical personification of the powers of Nature, would be incredible, were it not that other passages of his work leave no room for doubt upon the subject.
"On imagine une election naturelle que, pour plus de menagement, on me dit etre inconsciente, sans s'apercevoir que le contre-sens litteral est precisement la: election inconsciente." (P.52.)
"J'ai deja dit ce qu'il faut penser de l'election naturelle. Ou l'election naturelle n'est rien, ou c'est la nature: mais la nature douee d'election, mais la nature personnifiee: derniere erreur du dernier siecle: Le xix^e ne fait plus de
M. Flourens cannot imagine an unconscious selection -- it is for him a contradiction in terms. Did M. Flourens ever visit one of the prettiest watering-places of "la belle France," the Baie d'Arcachon? If so, he will probably have passed through the district of the Landes, and will have had an opportunity of observing the formation of "dunes" on a grand scale. What are these "dunes?" The winds and waves of the Bay of Biscay have not much consciousness, and yet they have with great care "selected," from among an infinity of masses of silex of all shapes and sizes, which have been submitted to their action, all the grains of sand below a certain size, and have heaped them by themselves over a great area. This sand has been "unconsciously selected" from amidst the gravel in which it first lay with as much precision as if man had "consciously selected" it by the aid of a sieve. Physical Geology is full of such selections -- of the picking out of the soft from the hard, of the soluble from the insoluble, of the fusible from the infusible, by natural agencies to which we are certainly not in the habit of ascribing consciousness.
But that which wind and sea are to a sandy beach, the sum of influences, which we term the "conditions of existence," is to living organisms. The weak are sifted out from the strong. A frosty night "selects" the hardy plants in a plantation from among the tender ones as effectually as if it were the wind, and they, the sand and pebbles, of our illustration; or, on the other hand, as if the intelligence of a gardener had been operative in cutting the weaker organisms down. The thistle, which has spread over the Pampas, to the destruction of native plants, has been more effectually "selected" by the unconscious operation of natural conditions than if a thousand agriculturists had spent their time in sowing it.
It is one of Mr. Darwin's many great services to Biological science that he has demonstrated the significance of these facts. He has shown that -- given variation and given change of conditions -- the inevitable result is the exercise of such an influence upon organisms that one is helped and another is impeded; one tends to predominate, another to disappear; and thus the living world bears within itself, and is surrounded by, impulses towards incessant change.
But the truths just stated are as certain as any other physical laws, quite independently of the truth, or falsehood, of the hypothesis which Mr. Darwin has based upon them; and that M. Flourens, missing the substance and grasping at a shadow, should be blind to the admirable exposition of them, which Mr. Darwin has given, and see nothing there but a "derniere erreur du dernier siecle" -- a personification of Nature -- leads us indeed to cry with him: "O lucidite! O solidite de l'esprit Francais, que devenez-vous?"
M. Flourens has, in fact, utterly failed to comprehend the first principles of the doctrine which he assails so rudely. His objections to details are of the old sort, so battered and hackneyed on this side of the Channel, that not even a Quarterly Reviewer could be induced to pick them up for the purpose of pelting Mr. Darwin over again. We have Cuvier and the mummies; M. Roulin and the domesticated animals of America; the difficulties presented by hybridism and by Palaeontology; Darwinism a rifacciamento of De Maillet and Lamarck; Darwinism a system without a commencement, and its author bound to believe in M. Pouchet, &c. &c. How one knows it all by heart, and with what relief one reads at p.65 --
"Je laisse M. Darwin!"
But we cannot leave M. Flourens without calling our readers' attention to his wonderful tenth chapter, "De la Preexistence des Germes et de l'Epigenese," which opens thus: --
"Spontaneous generation is only a chimaera. This point established, two hypotheses remain: that of pre-existence and that of epigenesis. The one of these hypotheses has as little foundation as the other." (P.163.)
"The doctrine of epigenesis is derived from Harvey: following by ocular inspection the development of the new being in the Windsor does, he saw each part appear successively, and taking the moment of appearance for the moment of formation he imagined epigenesis." (P.165.)
On the contrary, says M. Flourens (p.167),
"The new being is formed at a stroke (tout d'un coup), as a whole, instantaneously; it is not formed part by part, and at different times. It is formed at once; it is formed at the single individual moment at which the conjunction of the male and female elements takes place."
It will be observed that M. Flourens uses language which cannot be mistaken. For him, the labours of Von Baer, of Rathke, of Coste, and their contemporaries and successors in Germany, France, and England, are non-existent; and, as Darwin "imagina" natural selection, so Harvey "imagina" that doctrine which gives him an even greater claim to the veneration of posterity than his better known discovery of the circulation of the blood.
Language such as that we have quoted is, in fact, so preposterous, so utterly incompatible with anything but absolute ignorance of some of the best established facts, that we should have passed it over in silence had it not appeared to afford some clue to M. Flourens' unhesitating, a priori, repudiation of all forms of the doctrine of the progressive modification of living beings. He whose mind remains uninfluenced by an acquaintance with the phaenomena of development, must indeed lack one of the chief motives towards the endeavour to trace a genetic relation between the different existing forms of life. Those who are ignorant of Geology, find no difficulty in believing that the world was made as it is; and the shepherd, untutored in history, sees no reason to regard the green mounds which indicate the site of a Roman camp, as aught but part and parcel of the primaeval hill-side. So M. Flourens, who believes that embryos are formed "tout d'un coup," naturally finds no difficulty in conceiving that species came into existence in the same way.
 "Die Radiolarien: eine Monographie," p.231.
 Space will not allow us to give Professor Koelliker's arguments in detail; our readers will find a full and accurate version of them in the Reader for August 13th and 20th, 1864.
 If, on the contrary, we follow the analogy of the more complex forms of Agamogenesis, such as that exhibited by some Trematoda and by the Aphides, the Hyaena must produce, asexually, a brood of asexual Dogs, from which other sexless Dogs must proceed. At the end of a certain number of terms of the series, the Dogs would acquire sexes and generate young; but these young would be, not Dogs, but Hyaenas. In fact, we have demonstrated, in Agamogenetic phaenomena, that inevitable recurrence to the original type, which is asserted to be true of variations in general, by Mr. Darwin's opponents; and which, if the assertion could be changed into a demonstration, would, in fact, be fatal to his hypothesis.