EXPERIMENTAL EVOLUTION 
525 
departs from the average for 
that character, the less fre- 
quent is its occurrence. 
In another experiment, 
ears of corn, harvested from 
the same crop, were meas- 
ured and found to vary 
in length from 4}^ inches 
to 9 inches; the largest num- 
ber of ears (20) were 7 
inches long. The greater 
the departure from this 
length, in either direction, 
the fewer the individuals; 
for the lengths 4 inches and 
FIG. 392. Demonstration of 
Quetelet's law of fluctuating varia- 
bility in the length of seeds of the 
common bean (Phaseolus mdgaris) . 
Description in the text. (Redrawn 
from de Vries.) 
FIG. 393. Curve of fluctuating variation (Quetelet's curve), formed by 
arranging 82 ears of corn in ten piles, according to the length of the ears. 
The extremes were 4.5 and 9 inches. The ears were taken from unselected 
material from a field of corn. (After Blakeslee.) 
