NAVICULARTHRITIS. 
249 
being commonly but to one foot. Most horses, from the habit of 
leading in cantering or galloping with the off foot, exert the off 
limb in action more than the near ; and I find, on referring to my 
register, occurring in a given period of time, a proportion of ninety- 
three cases of lameness in the off fore foot to seventy-six in the 
near foot. 
The EXCITING Causes of navicularthritis will for the most part 
be found under the heading of what we denominate “ work a fact 
all our experience but tends to confirm, the simplest result of ob- 
servation being, that where most work is done there we find most 
horses lame in the navicular joints. At the same time, this gefieral 
cause of the mischief will be more or less operative, as regards 
navicularthritis or any disease in particular, accordingly as the 
kind of work the horse performs, the kind of foot he is possessed of, 
and the mode in which such foot is pared and shod, favours the 
approach of this or that disease. That navicularthritis may occur 
on a sudden, without there being any work in the question, from 
some mis-step or false step, some spring or jump, or leap or stumble, 
there is ample evidence to shew. A horse shall come fresh and 
sound out of his stable, make a stumble or a jump, and all at once 
fall dead lame : examination of the limb is immediately instituted ; 
nothing is found in the foot or elsewhere to account for the lame- 
ness, and the case at length turns out to have been from the first 
navicularthritis. or at least such lesion as is certain to lead thereto. 
This, it is true, may be regarded as an incidental occurrence. A 
tolerably certain way, however, of producing the disease would be 
to take a horse with a foot predisposed to it, and especially with 
one susceptible of it from having had the disease before, and give 
him a rattling trot or gallop upon a hard road, or take him for a 
day’s hunting, and over such a country as Surrey, where flints 
meet his foot at every step. 
In cavalry regiments, where the work of the horses is at times and 
seasons only such as can be called hard or trying, and that mostly 
during the summer, lengthened and accurate observation has shewn 
that cases of foot-lameness are more prevalent during such work- 
ing periods and seasons, and most of all prevalent in months when 
the ground upon which they exercise may be expected to be dry 
and hard. Looking back a period of eighteen years in my own 
regiment, I find recorded in the time 239 cases of ‘'lameness in 
the foot,” supposed to be navicularthritic. Dividing this period 
of eighteen years into two of nine each, I find but 71 of such 
cases occurred during the first half period ; 168 occurring in the 
course of the second : a circumstance to me accountable for on 
the score of there having been a smaller remount of horses in the 
former, as well as of the regiment having performed not only a less 
amount of work during the time, but that work consisting in slower 
