181 
ON THE EFFECT OF PRESSURE ON THE FEET OF 
HORSES, IN REPLY TO MR. REEVE. 
By u Amicus.” 
“ The sciences are not human inventions. Every science has for its basis a 
system of principles, as fixed and unalterable as those by which the universe is 
regulated and governed. Man cannot make principles; he can only discover 
them.” 
To the Editor of' 11 The Veterinarian .” 
Sir,—M y object was to induce Mr. Reeve to reconsider this 
subject in the same manner he did at p. 198, in The VE¬ 
TERINARIAN for April 1850, and my reasons were these : Mr. 
Reeve there gave “ the base and perpendicular to find the 
hypothenuse of the sole.” I knew there could not be a sole 
having for its perpendicular 5 of an inch, unless it had per¬ 
manently descended 3 of an inch, i. e., had become in this 
degree a flat sole; the perpendicular of a sole at this part, in a 
foot 5 inches wide, being 8 of an inch. 
Again, the crust is passive; the sole is the agent acting upon 
it, and, therefore, should alone have formed the bases of the 
right angled triangles. The statement should have been, base 
1 inch, 8 perpendicular 8 of an inch less, 6 of an inch equal to 
2 inches, the square of which is 4, equal to the square of the 
hypothenuse. 
There, again, the frog should have been retained, and the 
bases of the triangles should have been carried across the foot; 
as it thus shews, by descent of the hypothenuse, the degree of 
downward pressure on the frog, that Mr. Gloag was so parti¬ 
cular in describing as the results of his experiments; and which 
is one of the differences, a very important one, in Mr. Gloag’s 
physiology, from that of the late Professor Coleman, who con¬ 
sidered counter-pressure of the ground against the frog as the 
means of expanding the upper part of the heels and quarters, 
which is its secondary use, when it does happen. Mr. Gloag 
has proved that its primary use is its descent, and in this he 
also differs from Mr. B. Clark, who considered the use of the 
frog to admit of lateral expansion of the heels, from heel to toe, 
like a hinge shoe. Mr. B. Clark, at his lecture in 1813, held 
in one hand the crust and bars, from which the sole and frog 
had been removed by maceration, and put the fore-finger of 
the other on the point of the bars, and by pressure opened the 
heels in the above described manner, by the opening of the 
commissures, and Mr. Reeve closes his paper with the same 
theory. Here the circumstance of the sole abutting against 
