152 THE GENESIS OF SPECIES. [CHAP. 



tinued selection under domestication; and there is no 

 reason to suppose that any of the variations which have 

 been selected to form it have been other than gradual and 

 almost imperceptible. Suppose that it has taken five hun- 

 dred years to form the greyhound out of his wolf-like an- 

 , cestor. This is a mere guess, but it gives the order of the 

 magnitude." Now, if so, " how long would it take to ob- 

 tain an elephant from a protozoon, or even from a tadpole- 

 like fish ? Ought it not to take much more than a million 

 times as long ? " " 



Mr. Darwin 16 would compare with the natural origin of 

 a species " unconscious selection, that is, the preservation 

 of the most useful or beautiful animals, with no intention 

 of modifying the breed." He adds : " But by this process 

 of unconscious selection, various breeds have been sensibly 

 changed in the course of two or three centuries." 



" Sensibly changed ! " but not formed into " new spe- 

 cies." Mr. Darwin, of course, could not mean that species 

 generally change so rapidly, which would be strangely at 

 variance with the abundant evidence we have of the stabil- 

 ity of animal forms as represented on Egyptian monuments 

 and as shown by recent deposits. Indeed, he goes on to 

 say : " Species, however, probably change much more slow- 

 ly, and within the same country only a few change at the 

 same time. This slowness follows from all the inhabitants 

 of the same country being already so well adapted to each 

 other, that places in the polity of Nature do not occur until 

 after long intervals, when changes of some kind in the 

 physical conditions, or through immigration, have occurred, 

 and individual differences and variations of the right na- 

 ture, by which some of the inhabitants might be better 

 fitted to their new places under altered circumstances, 

 might not at once occur." This is true, and not only will 



15 " Habit and Intelligence," vol. i., p. 345. 



16 " Origin of Species," 5th edit, p. 353. 



