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tion, entertains grave doubts on this subject." For our own part, governed by the motto of the parent society for the promotion of natural knowledge, "nullius in verba," our attention was principally directed, in the first perusal of Mr. Darwin's work, to the direct observations of nature which seemed to be novel and original, and to the additional grounds, based on fact, on which a more lasting superstructure of the theory of the mutability of species might be raised. These observations, therefore, claim our notice before we proceed to discuss the general theory of the work.
No naturalist has devoted more painstaking attention to the structure of the barnacles than Mr. Darwin. In reference to the transitions of organs, and the probability of their conversion from one function to another, he states:—
"Peduncnlateil cirripedcs hnve two minnto folds of skin, called by me the ovigcrous frenn, which serve, through the means of a sticky secretion, to retain the eggs until they are hatched within tho sack. These cirripcdes hare no branchiae, the whole surface of the body and sack, including tho small frena, serving for respiration. The Balanidaj or sessile cirripedcs, on the other hand, have no ovigerous frena, tho eggs lying loose at tho bottom of the sack, in the well-enclosed shell; bat they have largo folded branchire. Now I think no one will dispute that the ovigcrous frena in the one family are strictly homologous with the branchio; of the other family; indeed, they graduate into each other."—P. 191.
That is, a series of modifications are affirmed to have been met with in different species, changing a respiratory into an ovigerous organ. Should this graduation of parts be confirmed, and the respiratory function of the folded membranes in Baianidaj be determined, Mr. Darwin will have contributed both an interesting observation, and a valuable discovery. But neither in the present work, nor in the two volumes published and illustrated at the cost of the Ray Society, are those relations of the folded membranes in the Balanidte with the heart or vascular system demonstrated, which could alone prove the respiratory function of such membranes.
Mr. Darwin has by no means limited himself to dissections of dead animals, but has devoted much time to observation of the living. Desirous of testing the truth of the assertions respecting the slave-making ants (.Formica Sanguined), he opened
"fourteen nests of that species and found a few slaves in all. Males and fertile females of the slave species (Format fusca) are found only in their proper communities, and have never heen observed in the nests of /'. sanijuinea, Tho slaves ore black, and not above half the size of their red masters, so that the contrast in their appearance is very great. When the nest is slightly disturbed, tho slaves occasionally come oat, and, like their masters, are much agitated and defend the nest: when the nest is much disturbed and the larva; and pupa? are exposed, the slaves work energetically with their masters in carrying them away to a place of safety. Hence, t is clear, that tho slaves feel quite at home. During the months of June and July, on three successive years, I have watched for many hours several nests in Surrey and Sussex, and never saw a slave cither leave or enter a nest. Durng tho present year, however, in the month of July (1859), 1 came across a community with an unusually largo stock of slaves, and I observed a few slaves mingled with their masters eaving the nest, anil marching along the same) road to a tall Scotch fir-tree, twenty-five vards distant, which they ascended together, probably n search of aphides or cocci. According to i In!n-r, who had ample opportunities for observation, in Switzerland, the slaves habitually work with their masters in making the nest, and :hcy alone open and close the doors in the mornng and evening; and, as Hubcr expressly states, heir principal office is to search for aphides. Another day my attention was struck by abont a score of the slave-makers haunting the same spot, and evidently not in scorch of food; they approached and were vigorously repulsed by an independent community of the slave species (F. fusca); sometimes as many as three of these ants clinging to the legs of the slave-making F. sanguinta. The latter ruthlessly killed their small opponents, and carried their dead bodies its food to their nest, twenty-nine yards distant; but they were prevented from getting any pupx to rear as slaves. I then dug up a small parcel of the pupa: of F. fusca from another nest, and put them down on n bare spot near tho place of combat; they were eagerly seized, and carried off by the tyrants, who perhaps fancied that, after all, they had been victorious in their late combat."—V. 221.
Many other direct observations on the J*. sanguined of England are recounted, and are contrasted with those first recorded by Huber, relative to the slave-holding F. rufetcens of Switzerland.
"Such are the facts, though they did not need confirmation by mo in regard to tlio wonderful instinct of making slaves. Let it be observed what a contrast the instinctive habits of F. songuinea present with those of the F. niftscens. The latter docs not build its own nest, does not determine its own migrations, docs not collect food for itself or its young, and cannot even feed itself: it is absolutely dependent on its numerous slaves. F. sanyuinea, ou the other hand, possesses much fewer slaves, and in the early part of the summer extremely few. The masters; determine when and where a new nest shall be formed, and when they migrate the masters carry the slaves. Both in Switzerland and England the slaves seem to have the exclusive caro of the lan-ie, and the masters alone go on slavemaking expeditions. In Switzerland the slaves and masters work together, making and bringing materials for the nest: both, but chiefly the slaves, tend, and milk, as it may be called, their •phidcs; and thus both collect food for the community. In England the masters alone usually leave the nest to collect building materials and food for themselves, their slaves, and larva-. So that the masters in this country receive much less service from their slaves than they do in Switzerland."—P. 223.
The instincts of the bee have received not less attention from Mr. Darwin than those of the ant; and he has also enriched this interesting part of natural history by new and original remarks.* Desirous of testing the mechanical hypothesis of the formation of the hexagonal cell, out of an original cylindrical form, by pressure of surrounding cylinders, Mr. Darwin
"separated two combs, and put between them a long, thick, square (rectangular ?)' strip of wax; the Dees instantly began to excavate minute circular pits in it; and as they deepened these little pits they made them wider and wider nntil they were converted into shallow basins, appearing to the eye perfectly true or parts of a sphere, and of about the diameter of a cell. It was most interesting to me to observe that wherever several bees had begun to excavate these basins near together, they had begun their work at such a distance from each other, that by the time the basins had acquired the above stated width (i.e. about tho width of an ordinary cell), and were in depth about one-sixth of tho diameter of tho sphere of which they formed a part, the rims of the basins intersected or broke into each other. As soon as this occurred, the bees ceased to excavate, and began to build up flat walls of wax on the lines of intersection between the basins, so that each hexagonal prism was built upon the festooned edge of a smooth basin, instead of on the straight edges of a three-sided pyramid as in the case of ordinary cells.1'—P. 228.
With regard to the mechanical origin of the bee's cell, Mr.-Darwin proceeds to say :—
"In one well-marked instance, I put the comb back into the hive, and allowed the bees to go on working for a short time, and again examined tho cell, and I found that the rhombic plate had been completed, and had become perfectlyJlat; it was
* In the remarkable volume recently published by Lord Brougham, entitled " Tracts, Mathematical and Physical," which have been produced by his lordship* at various times from tho year 1790 to the year 1S58. will be found nn excellent paper on the mathematical structure of bees' cells, read before the National Institute of France, by I,ord Brougham, in the French language, in May, 1868. It is a scientific and literary curiosity.
absolutely impossible, from the extreme thinness of the little rhombic plate, that they could have effected this by gnawing nwny tho convex side; and I suspect that tho bees in such cases stand in tho opposed cells and push and bend the ductile and warm wax (which, ns I have tried, is cosily done) into its proper intermediate plane, and thus flatten it.
"From tho experiment of tho ridge of vermillion wax, we can clearly see that if the bees were to build for themselves a thin wall of wax, :hcy could make their cells of tho proper shape, ]y standing at the proper distance from each other, by excavating at the same rate, and by endeavoring to make equal spherical hollows, bat never allowing the spheres to break into each other."—P. 230.
Mr. Darwin, while collecting objects of natural history in the rivers of Brazil, was surprised at the similarity of the fresh-water insects, shells, etc., and at the dissimilarity of the surrounding terrestrial beings, compared with the fauna of Great Britain, and he was led to ponder on this power, as it seemed, in fresh-water productions, of ranging widely. He offers many ingenious suggestions to account for the phenomena, and gives, what is of greater value, the following original observation and experiment:—
"Two facts which I have observed—and no doubt many others remain to bo observed—throw some light on this subject. When n duck suddenly emerges from a pond covered with duckweed, I have twice seen these little plants adhering to its back; and it luis happened to me in removing a little duckweed from one aquarium to another, that I have qnito unintentionally stocked tho one with fresh-water shells from tho other. But another agency is perhaps more effectual: I suspended a duck's feet, which might represent those of a bird sleeping in a natural pond, in an aquarinm, where many ova of freshwater shells wcro hatching; and I found that numbers of tho extremely minute and just hatched shells crawled on the leet, and clnng to them so firmly that when taken out of the water they could not bo jarred off, though at a somewhat more advanced ago they would voluntarily drop olT. These just-hatched molluscs, though aquatic in their nature, survived on the duck's feet, in damp air, from twelve to twenty hours; and in this length of time a duck or heron might fly at least six or seven hundred miles, and would bo sure to alight on a pool or rivulet, if blown across sen to an oceanic island or to any other distant point."—P. 385.
The mud adhering to the feet of wading birds may serve to transmit species of aquatic plants far away from their native streams.
"I do not believe (writes Mr. Dnrwin) that botanists are awaro how charged tho mud of ponds is with seeds. I have tried several little experiments, but will here give only the most striking case. I took, in February, three tablespoonfuls of mud from three different points beneath tho water, on tho edge of a little pond. This mud, when dry, weighed only six and three-fourths ounces." I kept it covered up in my study for six months, pulling up and counting each plant .is it grew. The plants were of many kinds, and were altogether five hundred and thirty-seven in number; and yet the viscid mud was all contained in a breakfast cup! Considering these facts, I think it would be an inexplicable circumstance if water-birds did not transport the seeds of fresh-water plants to vast distances, and if consequently the range of these plants was not very great. The same agency may have come into play with the eggs of some of the smaller fresh-water animals."— P. 386.
Facing the difficulty of the transport of fresh-water or land shell-fish across long tracts of ocean, on the supposition of a transporting bird occasionally resting on, or dipping in, the salt sea, or in the case of such shells adhering to drifted timber, Mr. Dar\rin made more experiments, and found—
"That several species did in this state withstand uninjured an immersion in sea-water during seven days : one of these shells was the Helix pomatia, and after it had again hybernated I put it in sea-water for twenty days, and it perfectly recovered. As this species has a thick calcareous opcrculum, 1 removed it, and when it had formed a new membranous one, I immersed it for fourteen days in sea-water, and it recovered and crawled away."—P. 397.
Pigeons being monogamous, and proverbial for their constancy, are peculiarly favorable for experiments and practices establishing and propagating varieties. Such varieties consequently have become, under the selective caro of man, numerous and extreme. Believing it to be best, in reference to the question of the origin of varieties, to study some special group, Mr. Darwin took up domestic pigeons, associated himself with several eminent pigeon-fanciers, and joined two of the London Pigeon Clubs. He gives descriptions of the leading varieties: and amongst his own observations, the following, perhaps, conveys the newest matter :—
"As the evidence appears to me conclusive, that the several domestic breeds of pigeon have descended from one wild species,—the Rockpigeon (Columba Iwia), — I compared young pigeons of various breeds, within twelve hours after being hatched; I carefully measured the proportions (but will not here give details) of the beak, width of mouth, length of nostril and of eyelid, size of feet and length of leg, in the wild stock, in pouters, fantails, runts, barbs, dragons, carriers, and tumblers. Now eomo of these birds, when mature, differ so extraordinarily in length and form of beak, that they would, I cannot doubt, be ranked in distinct genera, had they been natural productions. But when the nestling birds of these several breeds were placed in a row, though most of them could be distinguished from each other, yet their proportional differences in the above specified several points
were incomparably less than in the full-grown birds. Some characteristic points of difference —for instance, that of the width of mouth— could hardly be detected in the young. But there was one remarkable exception to this rule, for the young of the short-faced tumbler differed from the young of the wild rock-pigeon and of the other breeds, in all its proportions, almost exactly as much as in the adult state." — P. 445.
These are the most important original observations, recorded in the volume of 1859: they ore, in our estimation, its real gems,—few indeed and far apart, and leaving the determination of the origin of species very nearly where the author found it j but a rich mine of such researches is alluded to and promised by Mr. Darwin, in a more voluminous collection of his researches, extending over a period of eighteen years j and to these every naturalist now looks forward with keen interest.
The interdependences of living beings of different kinds and grades, and the injurious results of their interruption, have long attracted the attention of observant and philosophic naturalists. An undue importance indeed was at one time attached to this principle; it was deemed to be so absolute as that no one species could be permitted to perish without endangering the whole fabric of organization. So Pope sang :—
"From Nature's chain, whatever link you strike, Tenth or ten thousandth, breaks the chain alike."
Manifold subsequent experience has led to a truer appreciation and a more moderate estimate of the importance of the dependence of one living being upon another. Mr. Darwin contributes some striking and ingenious instances of the way in which the principle partially affects the chain, or rather net-work of life, even to the total obliteration of certain meshes. And truly, extinction has made wide rents in the reticulation as now represented by the co-affinities of living species!
"From experiments which I have tried, I havo found that the visits of bees, if not indispensable, are at least highly beneficial to the fertilization of our clovers^ but humble-bees alone visit the common red clover (Trifolium Pratense), as other bees cannot reach the nectar. Hence I havo very little doubt, that if the whole genus of humble-bees became extinct or very rare in England, the heartsease and red clover would become very rare, or wholly disappear. The number of humble-bees in any district depends in a great degree on the number of fieldmice, which destroy their combs and nests; and Mr. H. Newman, who has long attended to the habits of humble-bees, believes 'that more than two-thirds of them are thus destroyed nil over Kngland.' Now the number of mice is largely dependent, as every one knows, on the number of cats; and Mr. Newman says, 'Near villages and small towns I have found the nests of humble-bees moro numerous than elsewhere, which I attribute to tlic number of cats that destroy tho mite.' Hence it is quite credible that the presence of a feline animal in largo numbers in a district might determine, through the intervention first of mice and then of bees, tho frequency of certain flowers in that district 1"—P. 73.
This i« very characteristic of the ingenious turn of thought of our author [ the more sober, or perhaps duller, naturalist •would, no doubt, appreciate more highly a dry statement of investigations, suggested by the actual extinction of red clover, and tracing that extinction inductively, by the ascertained absence of humble-bees and mice, back to the want of cats in the neighborhood. For the direct observation, however (if it should be confirmed), of the exclusive relation olBombus terreatria, as the mechanical fecundator of Trifolivm pratense, natural history may be indebted to Mr. Darwin. We wish we could cite other instances augmenting this debt from the present work; its chief part, however, is devoted to speculations on the origin of species ; and its main object is the advocacy of a view which we find most clearly expressed in the following passage. Mr. Darwm refers to the multitude of tho individuals of every species, which, from one cause or another, perish cither before, or soon after attaining maturity.
"Owing to this struggle for life, any variation, however slight and from whatever cause proceeding, if it be in any degree profitable to an individual of any species, in its infinitely complex relations to other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring. The offspring, also, will thus have a better chance of surviving, for, of the ninny individuals of any species which arc periodically born, but n small number can suryirc. I have called this principle, by which each (light variation, if useful, is preserved, by the term of Natural Selection, in order to mark its relation to man's power of selection. We have seen that man by selection can certainly produce great results, and can adapt organic beings to his own use*, through tho accumulation of slight bat useful variations, given to him by the hand of Mature. But Natural Selection, as wo shall hereafter sec, is a power incessantly ready for action, and i- as immeasurably superior to man's feeble efforts, us tho works of Nature ore to those of Art."—P. 61.
The scientific world has looked forward with great interest to the facts which Mr. Darwin might finally deem adequate to the support of his theory on this supreme question in biology, and to the course of inductive original research which might issue in throwing light on "that mystery of mysteries." But having now cited the chief, if
not the whole, of the original observations adduced by its author in the volume now before us, our disappoin tment may be conceived. Failing the adequacy of such observations, not merely to carry conviction, but to give a color to the hypothesis, we were then left to confide in the superior grasp of mind, strength of intellect, clearness and precision of thought and expression, which might raise one man so far above his contemporaries, as to enable him to discern in the common stock of facts, of coincidences, correlations and analogies in Natural History, deeper and truer conclusions than his fellowlaborers had been able to reach.
These expectations, v/e must confess, received a check on perusing the first sentence in the book.
"When on board II.M.S. ' Beagle," as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to tho past inhabitants of that continent. These facts seemed to me to throw some light on tho origin of species—that mystery of mysteries, as it has been called by some of our greatest phi•.ers."—P. 1.
What is there, we asked ourselves, as we closed the volume to ponder on this paragraph,—what can there possibly be in the inhabitants, we suppose he means aboriginal inhabitants of South America, or in their distribution on that continent, to have suggested to any mind that man might be a transmuted ape, or to throw any light on the origin of the human or other species? Mr. Darwin must be aware of what is commonly understood by an " uninhabited island;" he may, however, mean by the inhabitants of South America, not the human kind only, whether aboriginal or otherwise, but all the lower animals. Yet again, why arc the freshwater polypes or sponges to be called " inhabitants " more than the plants? Perhaps what was meant might be, that the distribution and geological relations of the organized beings generally in South America, had suggested transmutational views. They have commonly suggested ideas as to the independent origin of such localized kinds of plants and animals. But what the "certain facts " were, and what may be the nature of the light which they threw upon the mysterious beginning of species, is not mentioned or further alluded to in the present work.
The origin of species is the question of questions in zoology; the supreme problem which the most untiring of our original laborers, the clearest zoological thinkers, and the most successful generalizes, have never lost sight of, whilst they have approached it with due reverence. We have a right to expect that the mind proposing to treat of, and assuming to have solved, the problem, should show its equality to the task. The signs of such intellectual power we look for in clearness of expression, and in the absence of all ambiguous or unmeaning terms. Now, the present work is occupied by arguments,' beliefs, and speculations on the origin of | species, in which, as it seems to us, the fundamental mistake is committed, of confounding the questions, of species being the re-! suit of a secondary cause or law, and of the j nature of that creative law. Various have been the ideas promulgated respecting its i mode of operation; such as the reciprocal' action of an impulse from within, and an influence from without, upon the organization (Demaillet, Lamarck); premature birth of an embryo at a phase of development, so distinct from that of the parent, as, with the power of life and growth, under that abortive phase, to manifest differences equivalent to specific (Vestiges of Creation); the hereditary transmission of what are called "accidental monstrosities ;" the principle of gradual transmutation by "degeneration" (Buffon) as contrasted with the "progressional" view.
In reference to the definition of species, Lamarck,* in 1809, cited, as the most exact, that of " a collection of like (scmblables) individuals produced by other individuals equally like them (pareils a eux)." But the progress of discovery, especially, perhaps, in palaeontology, led him to affirm that species were not as ancient as nature herself, nor all of the same antiquity; that this alleged constancy was relative to the circumstances and influences to which every individual was subject, and that as certain individuals, subjected to certain influences, varied so as to constitute races, such variations might and do graduate (s'avancent) towards the assumption of characters which the naturalist would arbitrarily regard, some as varieties, others as species. He comments in almost the words of Mr. Darwin, on the embarrassment and confusion which the different interpretation of the nature and value of such observed differences, in the works of different naturalists, had occasioned.! The true method of surveying the diversities of organization is from the simple to the compound forms, which course Lamarck affirms to be graduated and regularly progressive, save where local circumstances, and others influencing the mode of life, have occasioned anomalous diversities.
Cuvier had preceded Lamarck in specifying the kinds and degrees of variation, which his own observations and critical judgment of the reports of others led him to admit.
* Philosophic Zoologiquc, 8vo. 1809, vol. i. p. 61. tlb.p. 66.
"Although organisms produce only bodies similar to themselves, there are circumstances which, in the succession of generations, alter to a certain point their primitive form." • Here it may be remarked, that the whole question at issue hinges upon the proof of the determination of that limit of variety. Cuvier gives no proof that the alteration stops "at a certain point." It merely appears from what follows, that his means of knowing by his own and others' observations had not carried him beyond the point in question, and he was not the man to draw conclusions beyond his premises.
"Less abundant food," lio goes on to say, "makes the young acquire less size and forco. Climate more or less cold, nir more or less moist, exposure to light more or less continuous, produce analogous effects; bat, abovo oil, the pains bestowed by man on the nnimnl and vegetable productions whieli lie raises for his uses, the consecutive attention with which he restricts them in regard to exercise, or to certain kinds of food, or to influences other than those to which they would he subject in a state of nature, all tend to alter more quickly and sensibly their properties."
Cuvier admits that the determination by experiment of these variable properties, of the precise causes to which they are due, of the degree of variability and of the powers of the modifying influences, is still very imperfect (" mais ce travail est encore tres-imparfait.") The most variable properties in organisms are, according to Cuvier, size and color.
"Tho first mainly depends on abundance of food; the second on light and many other causes so obscure that it seems to vary by clmncc. The length and strength of the hairs arc very variable. A villons plant, for example, transported to a moist place, becomes smooth. Beasts lose hair in hot countries, but gain hair in cold. Certain external parts, such as stamens, thorns, digits, teeth, spines, arc subject to variations of number both in the more and the less; parts of minor importance, such as barbs of wheat, etc., vary as to their proportions; homologous parts ('des parties do nature analogue') change one into another, i.e., stamens into petals as in double flowers, wings into fins, feet into jaws, and wo might add, adhesive into breathing organs [as in the cose of the barnacles cited by Mr. Darwin]."
As to the alleged test of the difference between a species and a variety by the infecundity of the hybrid of two parents which may differ in a doubtful degree, Cuvier, in reference to this being the case when the parents are of distict species, and not mere varieties, emphatically affirms, " Cette assertion ne repose sur aucune preuve" (p. 11); it is at
* Cuvier, "Tableau El<!inentairc de THistoire Naturelle," 8vo. 1788, p. 9.