490 EQUILIBRIUM OF ANIMALS :—BASE OF SUPPORT. 
which its feet cover and inclose between them; and tl 
wider this space, in proportion to the height of the centre | 
gravity, the more stable will the equilibrium be, since tl 
body may be more displaced without being upset. Thus : 
fig. 231 the table a must be upset ; because the line of dire 
tion ¢ from the centre of gravity ¢ falls outside the base | 
support d; whilst the table b, although equally inclined, wi 
not be upset but will return to its proper place, because tl 
line of direction e from is centre of gravity ¢ falls within i 
base d. Hence an animal which is supported upon four le; 
will stand much more firmly than one which rests on ty 
only ; since its real base is the whole space included betwee 
its four points of support. And again, an animal is moi 
firm when standing upon two legs, than when resting upc 
one only. 
652. Moreover when an animal rests upon four legs, tl 
extent of its base is but little influenced by the size of th 
feet ; and thus to render ther 
broad would be to increas 
their weight without addin 
much to their use as support 
This is easily understood hb 
comparing a quadruped to 
four-legged table; if the leg 
are sufficiently strong to suppo 
the weight that rests upo 
them, it matters little in regaa 
to the steadiness ‘of the tabl 
whether they bear upon tk 
ground by mere points or by fl 
surfaces ; since it is the large su 
face that would be enclosed 
lines joining them, which const 
tutes the real base. Hence w 
find that, in most quadruped 
the limbs only touch the groun 
by slightly-dilated extremities ; and the number of fingers - 
reduced more and more, without diminishing their effect 2 
instruments of locomotion. Thus in Ruminant animals, « 
the Deer, the number of toes is reduced to two in each foot, a 
seen in fig. 232, where ¢ represents the tibia, ta the bones ¢ 
Fig. 232. Fig. 233. 
Foor or DEER. Foor or Horse. 
