peesident's addeess. 275 



together of the puzzle of Life. "He discovered the Missing Link" 

 in a sense other than that cited. "The Origin," wrote Huxley 

 {22, vol. ii, p. 197), "provided us with the working hypothesis we 

 sought." The highest tribute to the successful way in which Darwin 

 elaborated and drove home the Theory is that paid by its co-originator, 

 the veteran Alfred Walhice, who, while he realized the value and 

 scope of the Theory, modestly says {60, fide 15, p. 131), "I have felt 

 all my life, and I still feel, the most sincere satisfaction that 

 Mr. Darwin had been at work long before me, and that it was not 

 left for me to attempt to write the Origin of Species. I have long 

 since measured my own strength, and know full well that it would 

 be quite unequal to that task." 



Darwin naturally relied mainly on " JS'atural Selection" to explain 

 the " Origin of Species," and subsequent observers have not been 

 slow to perceive, or backward to demonstrate, that other agencies are 

 also concerned in the production of species, notably the action of 

 'environment.' What many cavillers have overlooked, however, is 

 that Darwin himself, at the close of the Introduction to the first 

 edition of the "Origin," says, " I am convinced that Natural Selection 

 has been the main but not the exclusive means of modification " 

 {19, p. 6), while in the sixth edition {20, p. 421) he concludes that 

 species have been modified " chieflj* through the naturtil selection 

 of numerous, successive, slight, favourable variations ; aided in an 

 important manner by the inherited effects of the use and disuse of 

 parts ; and in an unimportant manner, that is in relation to adaptive 

 structures, Avhether past or present, by the direct action of external 

 conditions, and by variations which seem to us in our ignorance to 

 arise spontaneously. It appears that I formerly underrated the 

 frequency and value of these latter forms of variation, as leading 

 to permanent modifications of structure independently of natural 

 selection." He returns to the point in a letter to Moritz Wagner in 

 1876, when he writes {22, vol. iii, p. 159), "In my opinion the 

 greatest error w^hich I have committed has been not allowing sufiicient 

 weight to the direct action of the environment, i.e. food, climate, 

 etc., independently of natural selection . . . "When I wrote the 

 ' Origin,' and for some years afterwards, I could find little good 

 evidence of the direct action of the environment ; now there is a large 

 body of evi<lence." 



The present, however, is neither the time nor the place to enter 

 into a lengthy disquisition on Darwin and his work ; this has already 

 been done by those competent for the task, while an excellent 

 discussion of Darwinism as it appears to-day has lately been published 

 by Kellogg (44)- 



The following brief general statement appears to me to best 

 epitomize our present knowledge on the subject, and may be permitted 

 on account of what follows. 



Every organism possesses an inherent capacity to vary in a greater 

 or less degree in certain directions more or less peculiar to itself. 



The influences of environment, using that word in its widest 

 possible sense to include all influences exterior to the organism 



