XVII THE METHOD OF ORGANIC EVOLUTION 369 



elimination of the unfit. AVith the above figures (which 

 would have to be enormously greater with many species) 

 we see that for every 80 born only 1 on the average 

 survives to breed. With such an amount of selection it 

 is evident that whenever it happened that the mean 

 point, or " typical centre " of the curve of variation, ceased 

 to be the most advantageous point in relation to the 

 whole conditions of existence, then a new typical centre 

 would rapidly be produced by the elimination of all which 

 diverged from it to any injurious extent. There could 

 not possibly be any permanent regression from the new 

 typical centre unless the inevitable survival of the fittest 

 in a rapidly increasing population can be got rid of 



We are now in a position to discuss Mr. Galton's 

 theory, that there are certain variations which possess 

 " organic stability," and that these are the real factors of 

 evolution " without any help whatever from the process of 

 selection." And first, what is the exact character of these 

 stable variations, which form races and ultimately new 

 species by their own inherent force of stability ? Is the 

 stability in relation to the actual conditions of the en- 

 vironment or altogether independent of those conditions ? 

 If the former, how did it come to be in harmony with them ? 

 If this harmonious relation depends upon a mere chance 

 coincidence, we have to consider the comparative rarity 

 of these large or discontinuous variations, and that only a 

 small proportion of them have the alleged character of 

 " stability." Moreover this class of variations is generally 

 a variation in a single part or organ, and Herbert Spencer 

 (as well as many other writers) has argued forcibly that 

 modifications of single characters would in all cases be 

 useless unless accompanied by the correlative modifications 

 of a number of other characters. I have myself shown 

 that in the case of ordinary variations this is no difficult}^, 

 because all characters are varying more or less in every 

 generation, and thus the needful harmonious relation 

 between the different organs or parts can be easily 

 maintained ; but in the case of these large exceptional 

 variations the difficulty is an overwhelming one. And we 

 must always remember that these alleged " stable " vari- 



VOL. I. B B 



