120 EVOLUTION 



variations that have been studied have proved 

 themselves to have remarkable staying power 

 in inheritance, being anything but liable to 

 swamping; and (3) that we have not, even 

 to this day, sufficient knowledge of what 

 Darwin never seems to have doubted, namely 

 the degree of heritability of the minute fluc- 

 tuations. It was probably a false step on 

 Darwin's part when he turned so fully away 

 from discontinuous variations. 



Modern Study of Variations. — One of 

 the great steps of progress in evolution lore 

 since Darwin's day has been what we see, for 

 instance, in Dr. J. A. Allen's pioneer measure- 

 ments of American birds (1871), in Bateson's 

 *' Materials for the Study of Variation" 

 (1894), and in the pages of the journal called 

 "Biometrika" — the recording and registra- 

 tion of the variations that do actually occur 

 in nature. A few results may be noted. 



It has been clearly shown that Darwin did 

 not in the least exaggerate the available 

 supply of raw material. "Even Darwin 

 himself," as Wallace says, "did not realize 

 how much and how universally w^ild species 

 vary. " It has been proved that great varia- 

 tion is as frequent in wild as in domesticated 

 animals. The fountain of change is even 

 more copious than was dreamed of. 

 - Another important fact has come out 



