{274} Several authors.{275} In the margin "Hogg" occurs as authority for this fact. For the reference, see p. 17, note 4.These facts must lead to the conviction, justly wonderful as it is, that almost infinitely numerous shades of disposition, of tastes, of peculiar movements, and even of individual actions, can be modified or acquired by one individual and transmitted to its offspring. One is forced to admit that mental phenomena (no doubt through their intimate connection with the brain) can be inherited, like infinitely numerous and fine differences of corporeal structure. In the same manner as peculiarities of corporeal structure slowly acquired or lost during mature life (especially cognisant in disease), as well as congenital peculiarities, are transmitted; so it appears to be with the mind. The inherited paces in the horse have no doubt been acquired by compulsion during the lives of the parents: and temper and tameness may be modified in a breed by the treatment which the individuals receive. Knowing that a pig has been taught to point, one would suppose that this quality in pointer-dogs was the simple result of habit, but some facts, with respect to the occasional appearance of a similar quality in other dogs, would make one suspect that it originally appeared in a less perfect degree, "_by chance_," that is from a congenital tendency{276} in the parent of the breed of pointers. One cannot believe that the tumbling, and high flight in a compact body, of one breed of pigeons has been taught; and in the case of the slight differences in the manner of hunting in young fox-hounds, they are doubtless congenital. The inheritance of the foregoing and similar mental phenomena ought perhaps to create less surprise, from the reflection that in no case do individual acts of reasoning, or movements, or other phenomena connected with consciousness, appear to be transmitted. An action, even a very complicated one, when from long practice it is performed unconsciously without any effort (and indeed in the case of many peculiarities of manners opposed to the will) is said, according to a common expression, to be performed "instinctively." Those cases of languages, and of songs, learnt in early childhood and _quite_ forgotten, being _perfectly_ repeated during the unconsciousness of illness, appear to me only a few degrees less wonderful than if they had been transmitted to a second generation{277}.{276} In the _Origin_, Ed. i., he speaks more decidedly against the belief that instincts are hereditary habits, see for instance pp.209, 214, Ed. vi. pp. 321, 327. He allows, however, something to habit (p. 216).

{277} A suggestion of Hering's and S. Butler's views on memory and inheritance. It is not, however, implied that Darwin was inclined to accept these opinions._Hereditary habits compared with instincts._ The chief characteristics of true instincts appear to be their invariability and non-improvement during the mature age of the individual animal: the absence of knowledge of the end, for which the action is performed, being a.s.sociated, however, sometimes with a degree of reason; being subject to mistakes and being a.s.sociated with certain states of the body or times of the year or day. In most of these respects there is a resemblance in the above detailed cases of the mental qualities acquired or modified during domestication. No doubt the instincts of wild animals are more uniform than those habits or qualities modified or recently acquired under domestication, in the same manner and from the same causes that the corporeal structure in this state is less uniform than in beings in their natural conditions. I have seen a young pointer point as fixedly, the first day it was taken out, as any old dog; Magendie says this was the case with a retriever which he himself reared: the tumbling of pigeons is not probably improved by age: we have seen that in the case above given that the young sheep inherited the migratory tendency to their particular birth-place the first time they lambed. This last fact offers an instance of a domestic instinct being a.s.sociated with a state of body; as do the "transandantes" sheep with a time of year. Ordinarily the acquired instincts of domestic animals seem to require a certain degree of education (as generally in pointers and retrievers) to be perfectly developed: perhaps this holds good amongst wild animals in rather a greater degree than is generally supposed; for instance, in the singing of birds, and in the knowledge of proper herbs in Ruminants. It seems pretty clear that bees transmit knowledge from generation to generation.Lord Brougham{278} insists strongly on ignorance of the end proposed being eminently characteristic of true instincts; and this appears to me to apply to many acquired hereditary habits; for instance, in the case of the young pointer alluded to before, which pointed so steadfastly the first day that we were obliged several times to carry him away{279}.This puppy not only pointed at sheep, at large white stones, and at every little bird, but likewise "backed" the other pointers: this young dog must have been as unconscious for what end he was pointing, namely to facilitate his master's killing game to eat, as is a b.u.t.terfly which lays her eggs on a cabbage, that her caterpillars would eat the leaves.So a horse that ambles instinctively, manifestly is ignorant that he performs that peculiar pace for the ease of man; and if man had never existed, he would never have ambled. The young pointer pointing at white stones appears to be as much a mistake of its acquired instinct, as in the case of flesh-flies laying their eggs on certain flowers instead of putrifying meat. However true the ignorance of the end may generally be, one sees that instincts are a.s.sociated with some degree of reason; for instance, in the case of the tailor-bird, who spins threads with which to make her nest will use artificial threads when she can procure them{280}; so it has been known that an old pointer has broken his point and gone round a hedge to drive out a bird towards his master{281}.{278} Lord Brougham's _Dissertations on Subjects of Science_, etc., 1839, p. 27.{279} This case is more briefly given in the _Origin_, Ed. i. p.213, vi. p. 326. The simile of the b.u.t.terfly occurs there also.{280} "A little dose, as Pierre Huber expresses it, of judgment or reason, often comes into play." _Origin_, Ed. i. p. 208, vi. p.320.{281} In the margin is written "Retriever killing one bird." This refers to the cases given in the _Descent of Man_, 2nd Ed. (in 1 vol.) p. 78, of a retriever being puzzled how to deal with a wounded and a dead bird, killed the former and carried both at once. This was the only known instance of her wilfully injuring game.There is one other quite distinct method by which the instincts or habits acquired under domestication may be compared with those given by nature, by a test of a fundamental kind; I mean the comparison of the mental powers of mongrels and hybrids. Now the instincts, or habits, tastes, and dispositions of one _breed_ of animals, when crossed with another breed, for instance a shepherd-dog with a harrier, are blended and appear in the same curiously mixed degree, both in the first and succeeding generations, exactly as happens when one _species_ is crossed with another{282}. This would hardly be the case if there was any fundamental difference between the domestic and natural instinct{283}; if the former were, to use a metaphorical expression, merely superficial.{282} See _Origin_, Ed. i. p. 214, vi. p. 327.{283} Give some definition of instinct, or at least give chief attributes. < p="">319, Darwin refuses to define instinct.> The term instinct is often used in