10 EVOLUTION MADE PLAIN 
so, but these senses and instincts still live in 
him, making up, indeed, far the larger part of 
his current everyday life; while his higher psy¬ 
chical life is merely the outgrowth and flower 
of them.” 
The.old formula was: “Man is governed by 
reason; brutes by instinct.” But science has 
proved that lower animals are not guided al¬ 
together by instinct, that many of their actions 
are the results of mental activities remarkably 
similar to reasoning. On the other hand man 
himself has instinct—and well for him that he 
has, for his reason, as yet, is only partially 
developed. If we will but subtract from the 
sum of man’s actions, not only those prompted 
by instinct, but those also that result from 
habit, custom, prejudice, and the emotions of 
anger, revenge, vanity, and other elemental 
passions, we will not feel like crying from the 
housetops that “man is governed by reason.” 
Man and the lower animals have similar dis¬ 
eases. He is liable to contract from, or com¬ 
municate to them, such diseases as glanders, 
hydrophobia, cholera, tuberculosis. Drugs, to¬ 
bacco and alcohol have the same effects on 
animals as on us. 
Of course the dog, the ape, the horse and 
man do not perfectly agree in their correspond¬ 
ing parts and in their natures—if they did they 
would belong to the same species—but their 
similarities are so remarkable that they have 
a profound meaning for the thoughtful, how¬ 
ever meaningless they may be to the thought¬ 
less and the prejudiced. 
In embryonic development are found evi¬ 
dences not only of man’s close relationship 
