It remains only to say a few words on the argument from the calculation of chances which is supposed to reduce the survival by natural selection of any particular useful variation almost or altogether to an arithmetical impossibility. ‘The advantage,’ we are told, ‘whatever it may be, is utterly outbalanced by numerical inferiority. A million creatures are born: ten thousand survive to produce offspring. One of the million has twice as good a chance as any other of surviving: but the chances are fifty to one against the gifted individual’s being one of the hundred survivors. No doubt the chances are twice as great against any one other individual, but this does not prevent their being enormously in favour of _some_ average individual[69].’ In this calculation it seems to be overlooked that every individual will vary more or less, and that out of a million variations there is a very great probability that _one_ should give much more than the amount of advantage which the calculation supposes. Nor does it follow that a variation conferring great advantage in the struggle for life should be great in comparison with a creature’s general organization. There is a very probable alternative, that when the advantages are exceedingly slight they may be shared by a great many, and that when falling to the lot of only one or a few, they may be exceedingly important. The doctrines of reversion and inheritance are pressed into the service of the arithmetical argument to show that the acquired advantage would be gradually diminished and finally lost. But Mr. Darwin tells us that, ‘when a new character appears, it is occasionally from the first well-fixed[70].’ The chances upon one principle that a character will not be transmitted are not worth consideration, if, under the operation of some other principle known or unknown, the transmission of the character actually takes place. We are asked whether one white man, introduced into an island otherwise inhabited only by negroes, would be likely to give the whole island eventually a white, or even a yellow, population. Without trying the experiment, we may perhaps safely answer in the negative. But the illustration loses much or all of its point, when we consider how little the circumstances of the experiment would correspond with what ordinarily happens in nature, how little we know whether the white man’s colour would be really an advantage or the reverse, and how complicated are the differences between a white man and a negro. If the blackness of the negro be due to Natural Selection in any considerable degree, we should expect it to suit the conditions which surround him in his native habitation better than a white skin would do. In this case the pallor introduced into the breed by a solitary stranger would gradually disappear in obedience to the principles of Natural Selection, not in opposition to them. To take once more the instance of the giraffe; the useful variation is