158 DOMESTICATED ANIMALS AND PLANTS 
about 68.6 inches for parents and 68.0 inches for children 
(see columns 17 and 16). The most significant fact about this 
table is its tendency to cluster about these average values, which 
are nearest represented by column 9 and row g. Where these 
two lines cross is the densest part of the table, — around the 
number 34. Note, too, how the arrays (columns or rows of 
figures) resemble the frequency distribution with which we 
became familiar in the chapter on Type and Variability. Each 
of these arrays has the characteristic shape, — large in the 
middle, dwindling at both ends. Moreover, this large middle 
is in a// cases, whatever the parentage, zot far from the middle 
point of this table, though the table is somewhat skewed by 
the difference in the parental heights. To note more particu- 
larly, consider the offspring of about the average parent (68.5 
inches, row g). Though these parents were all of an even 
height, their offspring were distributed from below 62.2 inches 
to 73.2, but the largest number (48) is very near to the average 
of the race. 
Again, note the offspring of the 65.5-inch parents, which are 
below the average height of parents. Here the range in the off- 
spring is from below 62.2 inches, as before, but stops at 72.2, 
with the highest numbers (11) at 66.2 and 67.2, both taller 
than their parcnts. Indeed, of this whole population of 66 
children of the 65.5-inch parents, all but 22, or exactly two 
thirds, are better than their parents. 
Still again, note the offspring of the 71.5-inch parents, which 
are extremely tall. Here the range is from 65.2 inches to above 
73-2, or over an inch shorter than their parents. Again, of the 
43 children of these extremely tall parents, 30, or nearly three 
fourths, are shorter than their parents. Again, of the 43 chil- 
dren of these extremely tall parents, 30, or nearly three fourths, 
are shorter than thetr parents. 
The principle is, that whatever the parents, — short, medium, 
or tall, —the offspring tend strongly toward the mean of the 
race. This principle of tendency toward mediocrity is known 
