THE 
VETERINARIAN. 
VOL. XVII, No. 195. MARCH 1844. New Series, No. 27 
LECTURES ON HORSES. 
By William PerCIVALL, M.R.C.S., Veterinary Surgeon 
First Life Guards. 
PROGRESSION. 
LOCOMOTION implies vaguely the act or power of moving 
from place to place, and is equally applicable to animals with and 
without feet ; PROGRESSION carries in its meaning the notion of 
feet, and signifies stepping forward : RETRO -GRESSION being its 
antagonist term — the word we use for stepping backward. 
From the bare facts of quadrupeds being known to be the fleet- 
est of the creatures that move upon the earth’s surface, those that 
are capable of the greatest feats of saltation, as well as of the 
greatest speed and endurance in running, we might safely infer 
that four legs constituted a number better calculated for progression 
than any other. Men can run and jump with, considering they have 
but two legs, surprising effect ; but neither in the act of progres- 
sion nor in that of saltation can they compete with certain qua- 
drupeds ; neither are many-footed creatures — centipedes , as some 
of them are denominated — to be compared in these respects with 
quadrupeds, or even, indeed, with bipeds : the number four ap- 
pearing, in relation to legs, to be that which most happily answers 
the purposes of succession in stepping and propulsion, as well as 
for that continual shifting of the centre of gravity which necessarily 
takes place in the transportation of the body. 
The CENTRE OF GRAVITY, in a quadruped standing with its 
legs in their natural position, will be found to fall anterior to a 
point equidistant from each of the four feet, owing to the pre- 
ponderance forward of the head and neck : the precise point upon 
which the line of gravitation will fall it will be difficult or impos- 
sible to determine, that in some inconsiderable degree continually 
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