{86} That is truly winged fish.

{87} The terrestrial woodp.e.c.k.e.r of S. America formed the subject of a paper by Darwin, _Proc. Zool. Soc._, 1870. See _Life and Letters_, vol. iii. p. 153.

The gradations by which each individual organ has arrived at its present state, and each individual animal with its aggregate of organs has arrived, probably never could be known, and all present great difficulties. I merely wish to show that the proposition is not so monstrous as it at first appears, and that if good reason can be advanced for believing the species have descended from common parents, the difficulty of imagining intermediate forms of structure not sufficient to make one at once reject the theory.

-- III. The mental powers of different animals in wild and tame state [present still greater difficulties] require a separate section. Be it remembered I have nothing to do with origin of memory, attention, and the different faculties of the mind{88}, but merely with their differences in each of the great divisions of nature. Disposition, courage, pertinacity , suspicion, restlessness, ill-temper, sagacity and reverse unquestionably vary in animals and are inherited (Cuba wildness dogs, rabbits, fear against particular object as man Galapagos{89}). Habits purely corporeal, breeding season &c., time of going to rest &c., vary and are hereditary, like the a.n.a.logous habits of plants which vary and are inherited. Habits of body, as manner of movement d^o. and d^o.

Habits, as pointing and setting on certain occasions d^o. Taste for hunting certain objects and manner of doing so,--sheep-dog. These are shown clearly by crossing and their a.n.a.logy with true instinct thus shown,--retriever. Do not know objects for which they do it. Lord Brougham's definition{90}. Origin partly habit, but the amount necessarily unknown, partly selection. Young pointers pointing stones and sheep--tumbling pigeons--sheep{91} going back to place where born.Instinct aided by reason, as in the taylor-bird{92}. Taught by parents, cows choosing food, birds singing. Instincts vary in wild state (birds get wilder) often lost{93}; more perfect,--nest without roof. These facts [only clear way] show how incomprehensibly brain has power of transmitting intellectual operations.{88} The same proviso occurs in the _Origin_, Ed. i. p. 207, vi. p.319.{89} The tameness of the birds in the Galapagos is described in the _Journal of Researches_ (1860), p. 398. Dogs and rabbits are probably mentioned as cases in which the hereditary fear of man has been lost. In the 1844 MS. the author states that the Cuban feral dog shows great natural wildness, even when caught quite young.{90} In the _Origin_, Ed. i. p. 207, vi. p. 319, he refuses to define instinct. For Lord Brougham's definition see his _Dissertations on Subjects of Science etc._, 1839, p. 27.{91} See James Hogg (the Ettrick Shepherd), Works, 1865, _Tales and Sketches_, p. 403.{92} This refers to the tailor-bird making use of manufactured thread supplied to it, instead of thread twisted by itself.{93} _Often lost_ applies to _instinct_: _birds get wilder_ is printed in a parenthesis because it was apparently added as an after-thought. _Nest without roof_ refers to the water-ousel omitting to vault its nest when building in a protected situation.Faculties{94} distinct from true instincts,--finding [way]. It must I think be admitted that habits whether congenital or acquired by practice [sometimes] often become inherited{95}; instincts, influence, equally with structure, the preservation of animals; therefore selection must, with changing conditions tend to modify the inherited habits of animals.If this be admitted it will be found _possible_ that many of the strangest instincts may be thus acquired. I may observe, without attempting definition, that an inherited habit or trick (trick because may be born) fulfils closely what we mean by instinct. A habit is often performed unconsciously, the strangest habits become a.s.sociated, d^o.tricks, going in certain spots &c. &c., even against will, is excited by external agencies, and looks not to the end,--a person playing a pianoforte. If such a habit were transmitted it would make a marvellous instinct. Let us consider some of the most difficult cases of instincts, whether they could be _possibly_ acquired. I do not say _probably_, for that belongs to our 3rd Part{96}, I beg this may be remembered, nor do I mean to attempt to show exact method. I want only to show that whole theory ought not at once to be rejected on this score.{94} In the MS. of 1844 is an interesting discussion on _faculty_ as distinct from _instinct_.{95} At this date and for long afterwards the inheritance of acquired characters was a.s.sumed to occur.{96} Part II. is here intended: see the Introduction.Every instinct must, by my theory, have been acquired gradually by slight changes of former instinct, each change being useful to its then species. Shamming death struck me at first as remarkable objection. I found none really sham death{97}, and that there is gradation; now no one doubts that those insects which do it either more or less, do it for some good, if then any species was led to do it more, and then escaped &c. &c.{97} The meaning is that the att.i.tude a.s.sumed in _shamming_ is not accurately like that of death.Take migratory instincts, faculty distinct from instinct, animals have notion of time,--like savages. Ordinary finding way by memory, but how does savage find way across country,--as incomprehensible to us, as animal to them,--geological changes,--fishes in river,--case of sheep in Spain{98}. Architectural instincts,--a manufacturer's employee in making single articles extraordinary skill,--often said seem to make it almost , child born with such a notion of playing{99},--we can fancy tailoring acquired in same perfection,--mixture of reason,--water-ouzel,--taylor-bird,--gradation of simple nest to most complicated.{98} This refers to the _transandantes_ sheep mentioned in the MS.of 1844, as having acquired a migratory instinct.{99} In the _Origin_, Ed. i. p. 209, vi. p. 321, Mozart's pseudo-instinctive skill in piano-playing is mentioned. See _Phil.Trans._, 1770, p. 54.Bees again, distinction of faculty,--how they make a hexagon,--Waterhouse's theory{100},--the impulse to use whatever faculty they possess,--the taylor-bird has the faculty of sewing with beak, instinct impels him to do it.{100} In the discussion on bees' cells, _Origin_, Ed. i. p. 225, vi. p. 343, the author acknowledges that his theory originated in Waterhouse's observations.Last case of parent feeding young with different food (take case of Galapagos birds, gradation from Hawfinch to Sylvia) selection and habit might lead old birds to vary taste and form, leaving their instinct of feeding their young with same food{101},--or I see no difficulty in parents being forced or induced to vary the food brought, and selection adapting the young ones to it, and thus by degree any amount of diversity might be arrived at. Although we can never hope to see the course revealed by which different instincts have been acquired, for we have only present animals (not well known) to judge of the course of gradation, yet once grant the principle of habits, whether congenital or acquired by experience, being inherited and I can see no limit to the [amount of variation] extraordinariness of the habits thus acquired.{101} The hawfinch-and _Sylvia-_types are figured in the _Journal of Researches_, p. 379. The discussion of change of form in relation to change of instinct is not clear, and I find it impossible to suggest a paraphrase._Summing up this Division._ If variation be admitted to occur occasionally in some wild animals, and how can we doubt it, when we see [all] thousands organisms, for whatever use taken by man, do vary.If we admit such variations tend to be hereditary, and how can we doubt it when we resemblances of features and character,--disease and monstrosities inherited and endless races produced (1200 cabbages).If we admit selection is steadily at work, and who will doubt it, when he considers amount of food on an average fixed and reproductive powers act in geometrical ratio. If we admit that external conditions vary, as all geology proclaims, they have done and are now doing,--then, if no law of nature be opposed, there must occasionally be formed races, [slightly] differing from the parent races. So then any such law{102}, none is known, but in all works it is a.s.sumed, in flat contradiction to all known facts, that the amount of possible variation is soon acquired. Are not all the most varied species, the oldest domesticated: who think that horses or corn could be produced? Take dahlia and potato, who will pretend in 5000 years{103} : perfectly adapted to conditions and then again brought into varying conditions. Think what has been done in few last years, look at pigeons, and cattle. With the amount of food man can produce he may have arrived at limit of fatness or size, or thickness of wool , but these are the most trivial points, but even in these I conclude it is impossible to say we know the limit of variation. And therefore with the [adapting] selecting power of nature, infinitely wise compared to those of man, that it is impossible to say we know the limit of races, which would be true kind; if of different const.i.tutions would probably be infertile one with another, and which might be adapted in the most singular and admirable manner, according to their wants, to external nature and to other surrounding organisms,--such races would be species. But is there any evidence species been thus produced, this is a question wholly independent of all previous points, and which on examination of the kingdom of nature ought to answer one way or another.{102} I should interpret this obscure sentence as follows, "No such opposing law is known, but in all works on the subject a law is (in flat contradiction to all known facts) a.s.sumed to limit the possible amount of variation." In the _Origin_, the author never limits the power of variation, as far as I know.{103} In _Var. under Dom._ Ed. 2, ii. p. 263, the _Dahlia_ is described as showing sensitiveness to conditions in 1841. All the varieties of the _Dahlia_ are said to have arisen since 1804 (_ibid._ i. p. 393).PART II{104}.{104} In the original MS. the heading is: Part III.; but Part II.is clearly intended; for details see the Introduction. I have not been able to discover where -- IV. ends and -- V. begins.---- IV. & V. I may premise, that according to the view ordinarily received, the myriads of organisms peopling this world have been created by so many distinct acts of creation. As we know nothing of the will of a Creator,--we can see no reason why there should exist any relation between the organisms thus created; or again, they might be created according to any scheme. But it would be marvellous if this scheme should be the same as would result from the descent of groups of organisms from [certain] the same parents, according to the circ.u.mstances, just attempted to be developed.With equal probability did old cosmogonists say fossils were created, as we now see them, with a false resemblance to living beings{105}; what would the Astronomer say to the doctrine that the planets moved according to the law of gravitation, but from the Creator having willed each separate planet to move in its particular orbit? I believe such a proposition (if we remove all prejudices) would be as legitimate as to admit that certain groups of living and extinct organisms, in their distribution, in their structure and in their relations one to another and to external conditions, agreed with the theory and showed signs of common descent, and yet were created distinct. As long as it was thought impossible that organisms should vary, or should anyhow become adapted to other organisms in a complicated manner, and yet be separated from them by an impa.s.sable barrier of sterility{106}, it was justifiable, even with some appearance in favour of a common descent, to admit distinct creation according to the will of an Omniscient Creator; or, for it is the same thing, to say with Whewell that the beginnings of all things surpa.s.s the comprehension of man. In the former sections I have endeavoured to show that such variation or specification is not impossible, nay, in many points of view is absolutely probable. What then is the evidence in favour of it and what the evidence against it.With our imperfect knowledge of past ages [surely there will be some] it would be strange if the imperfection did not create some unfavourable evidence.{105} This pa.s.sage corresponds roughly to the conclusion of the _Origin_, see Ed. i. p. 482, vi. p. 661.{106} A similar pa.s.sage occurs in the conclusion of the _Origin_, Ed. i. p. 481, vi. p. 659.Give sketch of the Past,--beginning with facts appearing hostile under present knowledge,--then proceed to geograph. distribution,--order of appearance,--affinities,--morphology &c., &c.Our theory requires a very gradual introduction of new forms{107}, and extermination of the old (to which we shall revert). The extermination of old may sometimes be rapid, but never the introduction. In the groups descended from common parent, our theory requires a perfect gradation not differing more than breed of cattle, or potatoes, or cabbages in forms. I do not mean that a graduated series of animals must have existed, intermediate between horse, mouse, tapir{108}, elephant [or fowl and peac.o.c.k], but that these must have had a common parent, and between horse and this parent &c., &c., but the common parent may possibly have differed more from either than the two do now from each other. Now what evidence of this is there? So perfect gradation in some departments, that some naturalists have thought that in some large divisions, if all existing forms were collected, a near approach to perfect gradation would be made. But such a notion is preposterous with respect to all, but evidently so with mammals. Other naturalists have thought this would be so if all the specimens entombed in the strata were collected{109}. I conceive there is no probability whatever of this; nevertheless it is certain all the numerous fossil forms fall in, as Buckland remarks, _not_ present cla.s.ses, families and genera, they fall between them: so is it with new discoveries of existing forms.Most ancient fossils, that is most separated s.p.a.ce of time, are most apt to fall between the cla.s.ses--(but organisms from those countries most separated by s.p.a.ce also fall between the cla.s.ses Ornithorhyncus?). As far as geological discoveries they tend towards such gradation{110}. Ill.u.s.trate it with net. Toxodon,--tibia and fibula,--dog and otter,--but so utterly improbable is , in _ex. gr._ Pachydermata, to compose series as perfect as cattle, that if, as many geologists seem to infer, each separate formation presents even an approach to a consecutive history, my theory must be given up. Even if it were consecutive, it would only collect series of one district in our present state of knowledge; but what probability is there that any one formation during the _immense_ period which has elapsed during each period will _generally_ present a consecutive history. [Compare number living at one period to fossils preserved--look at enormous periods of time.]{107} See _Origin_, Ed. i. p. 312, vi. p. 453.{108} See _Origin_, Ed. i. pp. 280, 281, vi. p. 414. The author uses his experience of pigeons for examples for what he means by _intermediate_; the instance of the horse and tapir also occurs.{109} The absence of intermediate forms between living organisms (and also as regards fossils) is discussed in the _Origin_, Ed. i.pp. 279, 280, vi. p. 413. In the above discussion there is no evidence that the author felt this difficulty so strongly as it is expressed in the _Origin_, Ed. i. p. 299,--as perhaps "the most obvious and gravest objection that can be urged against my theory."But in a rough summary written on the back of the penultimate page of the MS. he refers to the geological evidence:--"Evidence, as far as it does go, is favourable, exceedingly incomplete,--greatest difficulty on this theory. I am convinced not insuperable."Buckland's remarks are given in the _Origin_, Ed. i. p. 329, vi. p.471.