THE 
Of the various methods of animal motion, the walk claims 
our first consideration; it is characterized by an immu¬ 
table sequence of limb movements, common alike to man 
and beast, and there is little doubt of its having been the 
primitive system of locomotion employed, on their evolution, 
by all the terrestrial vertebrates. 
The law governing this method of progress is, that the 
naturally superior or stronger limb takes precedence of its 
inferior lateral limb in being lifted, thrust forward, and 
again placed on the ground. 
During the walk of a quadruped whose constant habit 
is to travel on the surface of the ground, and to employ all 
tour of its feet for the purposes of support and propulsion, 
the successive foot-impacts, assuming the notation to 
commence with the landing of O, will be— 
A-‘ A 4 
0-9 
A being, of course, followed by O in the next stride. 
WALK. 
When a horse is standing with the weight of the body 
equitably distributed over his four legs, and under these 
conditions commences to walk, the initiatory movement will 
invariably be made with a hind-foot ; the lateral fore-foot 
will next follow, and under the normal conditions of regu¬ 
lar progress this fore-foot will be lifted in advance of the 
suspended hind-foot being placed on the ground. 
The rapidity with which any one foot follows any other 
foot, or the duration of its contact with the ground, vary 
greatly, not only with different species of animals, but also 
with the same animal under apparently similar conditions. 
Series i illustrates twelve consecutive phases of two 
steps, or one half of a complete stride of a horse, walking 
at a speed of about four and a quarter miles an hour. In 
phase i, although O is still flat on the ground, it has practi¬ 
cally relinquished its function of support, and, as in 2, 3, 
and 4, that duty is imposed on the diagonals • A ; 4 
exhibits A a fraction of an inch only above the ground, but 
it assists the labours of • A in 5. 
In 6 A has broken the alliance; in this phase, and also 
in 7, 8, and 9, the right laterals alone furnish the needed 
support. O comes to the aid of these laterals in 10 
just as A is being advanced beyond ▲. The toe of • 
