342 vADDU'S VETERINARY MEDICINE AND SURGERY. 
foot. The navicular bone (sometimes called the shuttle-bcne) & 
so placed as to strengthen the union between the lower pastern 
and the coffin bone, and to enable the flexor tendon, which passes 
over it, in order to be inserted into the bottom of the coffin kone, 
to act with more advantage. There is a good deal of weight 
thrown on the navicular bone, and from the navicular bone t 
the tendon, and there is a great deal of motion or play between 
them in the bending and extension of the pasterns. It is verw 
easy, therefore, to conceive that from sudden concussion, or from 
rapid and unrestrained motion, the delicate membrane which: covers 
the bune, or the cartilage of the bone, may become diseased. The 
bone sometimes becomes ulcerated and fractured, so that it renders 
the horse almost perpetually lame. 
Symptoms.—The principal symptom of this affection is pointing 
of the foot. Ifthe horse be watched, when standing still in the 
stable or on the street, it wiil be noticed that the affected limb ig 
advanced or pointed in such a manner as to relieve the navicula: 
bone of any pressure from the flexor tendon, and this occurs in 
the chronic stage as well as in the acute. It will be observed, 
also, that the animal, when traveling, takes short steps, goes on 
the toe, and tries to favor the heel, or posterior parts, as much as 
possible. The favoring of the heel tends to destroy the function 
of expansibility of the hoof, and contraction of the same is the 
result. 
Treatment.—Should the disease be discovered early, that is, in 
the acute stage, the foot should be placed in a boot lined with a 
sponge. The latter is to be kept constantly wet with a portion 
of vinegar and water, equal parts. This may be continued for a 
period of twenty-four hours, at the end of which time bathe the 
coronct and heels with tincture of arnica. Light diet and perfect 
quiet, as in every other variety of inflammatory disease, are always 
wecessary. 
In old chronic cases we resort to counter-irritation, {rough re 
peatec ipplications of the acetate of cantharides. Should there b 
xny appearance of contraction, the heels of the hoof must be we!: 
cpened, and the walls of the hoof, near the heels, must be rasped 
thin, so as not only to favor the expansibility of the foot, but ale. 
with a view to relieve the navicular region of any undue pres: 
wre, 
