50 FIFTY YEARS OF DARWINISM 



steps, that it was f continuous ', not ' discon- 

 tinuous '. 



In his Presidential Address 1 to the British 

 Association at Cape Town in 1905, Sir George 

 Darwin argued from analogy against the ' con- 

 tinuous transformation of species '. It is impor- 

 tant to observe that the word ' continuous ' here 

 expresses uniformity in the rate of specific change, 

 and does not refer, as in the present address, 

 to the minuteness of the steps by which the 

 change is effected. The argument itself, which 

 is of great interest, is as follows : 



' In the world of life the naturalist describes those forms 

 which persist as species ; similarly the physicist speaks of 

 stable configurations or modes of motion of matter ; and the 

 politician speaks of States. The idea at the base of all 

 these conceptions is that of stability, or the power of resist- 

 ing disintegration. In other words, the degree of persistence 

 or permanence of a species, of a configuration of matter, or 

 of a State depends on the perfection of its adaptation to its 

 surrounding conditions.' 



After maintaining that the stability of states 

 rises and declines, culminating when it reaches 

 zero in revolution or extinction, and that the 

 physicist witnesses results analogous with those 

 studied by the politician and the historian, the 

 author continues : 



1 Report Brit. Assoc. (1905), 8. In this address as originally 

 delivered and printed in Fifty Years of Darwinism I fell into the 

 error of believing that Sir George Darwin was advocating evolution 

 by large steps. I was misled by the consideration that the word 

 ' continuous ' as used in the present address is a subject of contro- 

 versy among biologists, whereas a ' continuous transformation ' in 

 Sir George's sense would not, as I believe, be supported by any 

 naturalist. 



