460 
MYoITlS. 
in a muscle, is to produce a rigidity or contraction of its fibres ; 
that is to say, it is incapable of elongation to its full and natural 
extent; and as this change is one of gradual production, its true 
nature is unheeded : but another and opposite effect is also to be 
found — the state of flaccidity in which the contractile power is in 
a degree lost : this, a seeming paradox, is nevertheless true, and is, 
after all, but one other instance to shew that opposite extremes 
may be produced by one and the same exciting cause. 
Let us take for comparison two cases, common enough, and 
without any enlargement or thickening of the leg ; but simply, the 
one with the leg straight, the fetlock joint rather thrown forwards, 
the other with the leg bent forwards, projecting at the knee, and 
the pasterns thrown back. I have said that neither of these cases 
shall shew any of the ordinary forms of disease below the knee ; 
yet both shall be unsound, not limping with one leg, but lame of 
both : take the the first ; commence at the fetlock, the tendons are 
tense, firm, and have a metallic-like feel ; but their superficies par- 
ticularly well-defined, the suspensory-ligament less tense than 
usual, the knee straight, the arm hard and the muscles well-de- 
fined, especially the flexors ; but look closer, and you will perceive 
that the bodies of these muscles are shorter, the tendons appear to 
be given off higher up the arm than usual, and the leg has just 
the appearance which the limb assumes at that period after a 
death-blow, when the whole of the muscular fibres of the body 
contract with the last efforts of expiring life. Now take the 
second condition : instead of the leg appearing as if it were short- 
ened by the violent effort of the flexor muscles, it looks as if it 
would become longer if the bones would admit of it, just as a long 
man doubles himself to be able to lie down on a short bed ; the 
fetlock is thrown back, the knee thrown forwards, the suspensory 
ligament is tenser than the tendons, which are flabby, the muscles 
of the arm are in the same condition, and, if you look closer, it 
will be seen that the tendons appear as if given off unusually low 
down the arm; and hence it is often said of such horses, that the 
leg has no right to have gone in such a way, for what a good arm 
there is, and this appearance also applies very generally to the leg. 
But let us proceed a little farther in our investigation, and give 
each of these horses a brisk trot for a few minutes ; get them, as 
the jockeys say, “ warm,” and then these appearances are greatly 
removed : sometimes they will for a few minutes disappear ; in 
the first, the contracted fibres are relaxed — in the second, the re- 
laxed fibres are, by the stimulus of exertion, brought more into 
action — simply the result of stimuli : let them stand till this has 
subsided, and the pristine condition returns. 
