394 The Bird 
When one trains in college for a long-distance race, 
one rule to observe is, never touch your heels to the ground; 
run wholly on the ball of the foot. Untold centuries 
ago, wise old Nature whispered the very same direction 
to those of her children who had most need to run for 
their lives in life’s great race, and down through the 
ages some of them have never broken training. When 
an animal acquires 
great speed in running 
or leaping, there is a 
tendency for one toe 
to become greatly en- 
larged at the expense 
of the others, as is 
seen in the case of the 
horse, the kangaroo, 
and the ostrich. 
In the horse only 
the middle toe is 
functional, the second 
and fourth having de- 
generated into the 
small splint-bones at 
Fic. 308.—Feet and legs of Cassowary. 
the side of the leg. The kangaroo progresses upon 
the fourth and fifth toes, the second and third being 
small and skin-bound. The ostrich has but two toes, 
one of which, the third, as in the case of the horse, is 
very large and armed with a thick claw, which, hoof- 
like, grows close to the toe. This toe supports most of 
the bird’s weight, while the fourth or outer toe is only 
