734 An Exegesis of Darwinism. [December, 
duftions will have often have been exposed to more sudden 
and to less continuously uniform conditions ” (ii., 401). We 
shall also presently see that Mr. Darwin considers lasting 
rather than sudden influence to be the inducement of the 
tendency to vary. . 
For further evidence that “natural selection acts ow/y by 
the preservation and accumulation of small ” (p. 75 ) t* ^ n ~ 
finitesimally small ” ed. i. p. 95 J variations, consult the 
works cited passim. 
The case is similar as regards instindts ; that is to say, 
“ no complex instindt can possibly be produced through 
natural seledtion, except by the slow and gradual accumula- 
tion of numerous slight, yet profitable variations” (p. 207). 
“ With respedt to the lapse of time not having been 
sufficient for the assumed amount of organic change . . . 
this objedtion, as urged by Sir William Thomson, is 
probably one of the gravest as yet advanced ” (p. 409). 
11. In proof of this I may refer to works cited, passim ; to 
the ever-recurring phrase “ accumulation of slight successive 
variations”; to the constant insisting that “there is no 
necessity for supposing” simultaneity; to his distinction 
between initial variation and final co-adaptation (ii., 312), 
and to section 7 ante ; for the question of co-ordination may 
be “ put out of court ” if there be no co-ordinator. Maybe 
co-ordination does occur now and then — that is, a variation 
would fail to benefit were it to occur alone, or a prejudicial 
variation be neutralised by a concomitant one-— but it would 
be accidental — a word often used and well defended by Mr. 
Darwin ; a word like “ slight ” and “ accumulation,” which 
is one of the vertebrae of Darwinism. 
12. This is a very important sedtion, and is really one 
with Section 14. 
“ The many slight differences which appear in the off- 
spring of the same parents, or which it may be presumed have 
thus arisen, . . . may be called individual differences” (p. 34), 
and Mr. Darwin “ looks at individual differences, though of 
small interest to the systematist, as of the highest importance 
for us, as being the first steps towards such slight varieties ” 
as ultimately become species (p. 41). “ Under the term of 
‘ variations ’ it must never be forgotten that mere individual 
differences are included ” (p. 64, also p. 80) ; and all “ the 
individuals of the same species differ in some slight degree 
from each other” (p. 84). We read of variations “useful 
to each being's own welfare ” (p. 102) ; “ if any one being 
varies ever so little ” it may supplant “ some other inha- 
bitant ” (p. 143). Confer ii., 276. This individual variability 
