VARIATION AND DIFFERENTÏATÏON 179
'
from the study of 5
shes,
from these—« material errors than from?
the normal variation of the shes thems‘ielves;, A' pure .
«
*
group therefore is very difcult to
but it should be
aimed at.
,
,
—
,
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,
,
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The importance of the.use of the mathematical method
of treating variations
in
,
,
drawing c0nclusions.
One is
to,—, think
:
characters are not constant but vary,—up, and down about a
in this Wayone
habit ofbalancing;
the possibilities, Thé mathematiCal
extended into
the calculation of_the correla—
tion 'Ïbetween tWovarÿing Characters, the death rate or
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aga- ……ä1
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”ss
FrG46—Theformôf shesexpmssed bÿ{Ço—_brdiriaté lines}
,
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d’Amy
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Î Selection of individuals and the félatiohbetweenparenæ
,
and osPring, and has everywhere prdved'its
'
,
Of great interest and promise also is the graphic method
’
of studying larger variations in form which has ,been
intro—,
' r—î L
ducedz;recently into the study of shes by Prof.
W
Thompson In this method the form of a sh is represented—?
byasyätem of
lines and we can, see how from one
,
,
'
form, many
be: derived,by a simple
‘
ment of.thé'ln either îbÿ changing the ,ang1e,fth
,
,
o_rby
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