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 all cases, whatever the parentage, not 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 6 5. 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 parents. 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 7 1.5 -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 their 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 



