178 THE GENESIS OF SPECIES. 



average individual 1 .' 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 sup- 

 poses. 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 di- 

 minished and finally lost. But Mr. Darwin tells us 

 that, ' when a new character appears, it is occasionally 

 from the first well-fixed 2 .' 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 



1 'Genesis of Species,' p. 57, quotation (somewhat obscure as it stands) 

 from the North British Review for June, 1867. 



2 'Animals and Plants under Domestication,' vol. ii. p. 63. 



