160 DOMESTICATED ANIMALS AND PLANTS 
that mediocrity is the most common and the most likely lot of 
man, and that regression is always at work. 
Progression. Now let us look at the other side of the ques- 
tion and see what is to be found after having disposed of this 
relatively large number of mediocre individuals, and let us see 
if, after all, the exceptional parent has not something to his 
advantage in the matter of offspring. 
Note again that the other end of this array of the offspring 
of the 70.5-inch parents shows 17 individuals, or exactly one 
fourth, better than their exceptionally good parents. Not only 
is this true, but the higher we get among the exceptional parents, 
— 71.5, 72.5, etc., —the more is this true and the larger is the 
proportion of exceptional offspring. This is progression, and, as 
a principle, it is just as true and just as much to be counted on 
as are regression and mediocrity. 
This principle of progression is the one that insures the 
results from natural selection and the survival of the fittest in 
nature, just as it is the one that insures that selection anywhere 
will be followed by offspring, some portion of which, not all, will 
be a distinct improvement over even their exceptional parents. 
It is on this principle that we rely for most of our improvement 
of domesticated animals and plants, and as it is the most impor- 
tant principle in evolution, the student is urged to remember it. 
The promptness and rapidity with which improvement follows 
selection under this principle of progression is best shown by 
the opposite table exhibiting the results of Dr. Hopkins’s ex- 
periments in altering the oil content of the grain of corn. 
In this experiment ears of the highest and others of the 
lowest oil content obtainable were planted in successive years. 
The table shows the results in the crop both as to distribution 
and average for each of nine years, and is the best exhibition 
known to the author of the principle of progression and the 
results of selection. 
In the study of this table it will be noticed that the oil content 
of the original seed was 4.70 per cent, but that the strain 
