72 Luck, or Cunning ? 
which still remains the sheet anchor of the early evolu- 
tionists. They believe, in fact, that more organic wealth 
has been made by saving than in any other way. The race 
is not in the long run to the phenomenally swift nor the 
battle to the phenomenally strong, but to the good average 
all-round organism that is alike shy of Radical crotchets 
and old world obstructiveness. Festina, but festina lente 
—perhaps as involving so completely the contradiction 
in terms which must underlie all modification—is the 
motto they would assign to organism, and Chi va piano 
va lontano, they hold to be a maxim’as old, if not as 
the hills (and they have a hankering even after these), 
at any rate as the ameeba. 
To repeat in other words. All enduring forms establish a 
modus vivendi with their surroundings. They can do this 
because both they and the surroundings are plastic within 
certain undefined but somewhat narrow limits. They are 
plastic because they can to some extent change their habits, 
and changed habit, if persisted in, involves corresponding 
change, however slight, in the organs employed ; but their 
plasticity depends in great measure upon their failure to 
perceive that they are moulding themselves. If a change 
is so great that they are seriously incommoded by its 
novelty, they are not likely to acquiesce in it kindly 
enough to grow to it, but they will make no difficulty about 
the miracle involved in accommodating themselves to a 
difference of only two or three per cent.* 
As long as no change exceeds this percentage, and as 
long, also, as fresh change does not supervene till the 
preceding one is well established, there seems no limit to 
the amount of modification which may be accumulated in 
the course of generations—provided, of course, always, 
that the modification continues to be in conformity with 
* See Professor Hering’s “‘ Zur Lehre von der Beziehung zwischen 
oat und Seele. Mittheilung iiber Fechner’s psychophysisches 
esetz.’ 
