56 
PROOFS OF EVOLUTION. 
animal teeth, peculiar muscles and hairy covering 
possessed by some men and women. The barnacle, 
once a free-swimmer, is now a lazy ride-stealer, a 
free-booter and pirate of the sea, threatening to 
scuttle the ship. Some island insects and many 
varieties of birds have lost the power to fly by 
long disuse of their wings, safety and food not 
requiring flight. The whale has lost his ability to 
walk on dry land. In general, when any organ 
has become useless, it tends to retrogression, and 
finally becomes rudimentary. Nature abhors the 
useless. But this reversion is always slow, as 
Heredity is ever jealous of her store. 
Reversions are but eddies in the great stream of 
Evolution, and like eddies show the direction of 
the current. It is as though Nature had sent a 
courier back a little way to guide us more clearly 
on in our investigations. This feature of Evolu¬ 
tion, theology should accept since it recognizes the 
principle of “ back-sliding.” The mites and ticks 
have doubtlessly fallen from spiders and scorpions. 
The insect, Stylops, with aborted wings, has sunk 
from a free-flyer to the ignoble life of a parasite. 
In closing this branch of the subject I will 
quote Professor Wilson: “While progressive Evo- 
