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ATROPHY OF THE PLANTAR CUSHION. 369 
F.—The observation of some pathological facts furnishes us a 
sure proof that the velvety tissue of the anterior region cannot 
be submitted to the slightest pressure from the bone or the 
sole without the immediate manifestation of a severe lameness. 
( a .) When a horse accidentally loses his shoe the lameness becomes 
visible only when the sole is too thin, either from the cutting by 
the blacksmith or from wearing, and that then it gives way to 
the pressure from the ground. (7a) The want of hollowness (ajust- 
ure) of the shoe does not produce lameness unless when the shoe 
is too thin or that the sole, thinned too much, gives way to the 
pressure. ( c .) In the case of acute laminitis the lameness is most 
certainly in great part, the effect of the compression of the velvety 
tissue by the os pedis, which, pushed by the hypertrophied lami¬ 
nated tissue, executes a motion backwards and downwards bv its 
anterior border. 
So far we have reached conclusions as to the fixity of the os 
pedis by deduction ; let us now do it by induction. To verify ex¬ 
perimentally, if the pressure upon the velvety tissue by the os pedis 
was painful, we have made upon the anterior foot of a glandered 
horse a solution of continuity on a level with the superior face of 
the sole, involving the wall almost in its entire thickness, leaving, 
however, a thin layer of horn over the living tissues be¬ 
neath, thus avoiding any local pain and, therefore, any false inter¬ 
pretation of the results of the experiment. After this operation 
a severe lameness showed itself; the resting upon the leg was 
done only after much hesitation and as much as possible on the 
posterior parts of the foot, as in acute laminitis. 
To resume, for us, as for M.M. Lafosse, Goyau, etc., the os 
pedis is immovable in the horny box, it is suspended to the wall, 
to which, exclusively, it transmits integrally and without a real 
movement downward, the pressure that it receives. 
The closing of the edges of a toe crack at the moment of rest, 
due “ to the traction of the os pedis inside of the arch represented 
at the toe by the wall” (L. Lafosse) proves to us, however, that 
though deprived of elasticity, the tissues which unite the os pedis 
to the horny box are not entirely inextensible, and that there must 
exist a motion of the bone downwards. But, as said M. Lafosse, 
