CHAPTER XXIX 
ON EVIL IN SMALL DOSES 
In all our theories of evolution there is a gap, and one 
that is fatal, for no argument can be considered complete, 
rounded off, and quite satisfactory until it is adequately 
filled in. , 
This weak point is the origin of variations. We have 
seen that climate-changes produce, 1n all vegetable cells, 
modifications which are of the nature of fitting responses 
to a new crisis, But how and why are those modifica- 
tions, those fitting responses always or at any rate so 
frequently ready to deal with the new emergency ? 
It is no answer to refer with Weissmann to the germ 
cells, which are, according to him, immortal, irrespon- 
sible, and entirely uninfluenced by the experiences of the 
individual. 
The mutant of De Vries is again not an explanation, 
but a new name for a change of type. 
Many attempts have been made to trace the number 
and character of variations by direct observation and 
measurement, 
Some of these researches involved an enormous 
amount of arithmetical calculation and of mathematical 
ingenuity which unfortunately makes it impossible for 
any one save mathematicians to appreciate them as they 
deserve.! 
But on the whole these biometrical researches dis- 
tinctly show that in any one generation, and if a single 
measurable character is taken, the majority of individuals 
are found to have the average character, and that those 
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