LAMENESS IN HORSES. 
66 
the horny frog, a part to which Bracy Clark has given the name 
of Frog-stay ; and the mortice sort of connexion thus subsisting 
between the sensitive foot and horny hoof, while it operates in 
preventing any dislocation between them, at the same time 
admits of such motion between the one and the other as is 
requisite for the play or performance of the functions of their 
several respective parts during the time the animal is in action. 
But motion of no kind, however limited, can go on, especially 
between organized and inorganized parts, without lubrifaction of 
some sort, and this is, in the instance in question, provided for by 
a peculiar sebaceous kind of secretion known to us more per- 
haps by peculiarity of odour than by any other property it may 
possess. This secretion naturally escapes through the pores of 
the horn into the cleft of the frog where it becomes absorbed 
and disappears. Should it, however, from irritation or inflam- 
mation of the parts secreting it, become so redundant in quan- 
tity as to give rise to the appearance of moisture in the cleft, 
and perceptible smell likewise — and it never does so without 
undergoing at the same time alteration in quality — the dis- 
charge of it constitutes frush. Coleman used to compare this 
secretion to the exudation taking place between the toes of our 
own feet, to prevent them growing together ; and, no doubt, 
some similar purpose is answered by it in the cleft ; though I 
would rather make a comparison between the secretion in the 
axilla of man and that in the cleft of the frog, seeing that there 
is something in both instances beyond mere exposed superficies. 
Bracy Clark has represented frush to be a fracture of the 
frog-stay ; and has distinguished it into natural and secondary 
or acquired. “ The frog-stay,” he says, is “ the last of the foot 
in obtaining its perfect growth and consolidation — being in some 
perfected at two years and a half, in others not until three and 
a half or four; and, if opposed by natural weakness or exter- 
nally destructive agents of the horn, such as wet, dirt, urine, 
& c., then the frog will never be properly closed, and a frush 
will be the consequence through life *' 7 In proof of which 
opinions being founded in fact, he gives an account of having 
visited some colts belonging to the East India Company at 
pasture near Epping Forest, and finding several among them 
with frushes : a circumstance plainly explicable in my mind by 
the “ place where they were confined being,” as he himself 
states, “ particularly wet.” 
Frush is only on rare occasions attended with 
Lameness. — Horses having frushes — and the exceptions, in a 
general way, are not numerous — appear to go, and to do their 
* See his “Essay on Running Frush. 1 
