644 
NAVICULAR DISEASE. 
There is no particular clanger in passing frog-setons, though some care 
is required to avoid injuring the perforans tendon; the loop of tape must 
not be left too long, as it may be caught by the other foot and torn out. 
Restive horses require to be thrown for operation ; it is then convenient 
to fasten the limb to a broad plank provided with a long handle, by 
which it is steadied (see p. 84 of Dollar’s “ Operative Technique ”). 
The seton needle must be regularly but not too sharply curved ; some 
operators prefer a nearly straight needle, similar to that used in cellulitis 
of the fihro-fatty frog. 
If setoning fails, nothing remains but to perform neurectomy (see 
section on “Ring-bone ”). Holler doubts the utility of resection of the 
flexor perforans tendon, as in his hands it has usually left the horse 
either permanently lame or has necessitated so long a rest as to be of no 
practical service. 
A valuable carriage-horse, which had for a long time suffered from 
navicular disease, contracted acute inflammation of the navicular joint in 
consequence of bruised sole. Operation was at once resorted to, and the 
navicular bone and perforans tendon found to be chronically diseased. The 
case did well, and the horse returned to work, but for several months trotted 
slightly lame. 
Proper shoeing is of great importance, both in preventing and treating 
this disease. In general, it is well to shorten the toes and lengthen the 
heels, either by suitably paring the foot or by applying leathers or shoes 
with thick heels. 
In marked contraction of the foot, indiarubber or cork pads or long- 
heeled shoes may be employed. Defay’s shoes sometimes diminish 
lameness considerably ; their action is assisted by moderate exercise on 
soft ground and by foot-baths (see Dollar and Wheatley’s “Handbook of 
Horse-shoeing ”). 
Tenotomy, recommended by Smith to assist adhesion of the perforans 
tendon to the navicular bone, has not proved successful. 
XI.—DERMATITIS IN THE FETLOCK REGION. MUD- 
FEVER—CRACKED HEELS—GREASE. 
The terms “mud-fever,” “grease,” &c., have been used since olden 
times to designate a series of disease processes in the skin about the 
fetlock, particularly on its flexor surface, the nature and course of which 
are exceedingly varied. Certain characters are, however, common to all 
forms of these diseases, viz., their point of origin in the heel, their 
inflammatoiy natuie, and spontaneous appearance. The diseases may 
be divided into four varieties:— 
(1) An erythematous. 
(2) An exanthematous, typified by “mud-fever.” 
