478 
H. S. DRAKE. 
branes lining the joint are crushed and bruised by the very ma¬ 
terial which nature had bestowed as a defense.” 
We learn from this writer that the bruising of the synovial 
membrane lining this joint is the veritable source of this dis¬ 
ease, it is engendered in the stable, but becomes permanently 
established by sudden violence out of it. Horses doing fast 
work on our hard roads, and those subject to the whims of fash¬ 
ion by being trained to high knee action are the ones that suffer 
most from this dreaded disease. 
From the time of its discovery, Turner shows conclusively 
that he was acquainted with the cause of navicular disease, and 
its pathological changes. 
Symptoms .—In the early stage the symptoms are obscure. 
The animal may be taken suddenly lame for a few days and 
then the lameness may entirely disappear for a short period, 
only to reappear in a more violent form, which finally becomes 
constant and aggravated. In the primary stage there may be 
heat about the base and posterior part of the foot. But in some 
instances there is no perceptible change in the temperature 
about the parts. One of the most characteristic symptoms is 
pointing of affected foot when at rest, and clean appearance of 
limb due to atrophy of muscles from imperfect use. This may 
be seen before the lameness is manifested. The affected foot 
always takes a short step and the toe of the foot first strikes the 
ground, so the shoe is most worn at that point, shows a stum¬ 
bling gait, and when both feet are affected at the same time, 
shows a stilty movement, as though he had both legs tied 
closely together. When made to work shows much pain and 
sweats profusely, also shows much pain on pressure over the 
seat of disease. There never was yet a philospher who could 
withstand a toothache, but think of a poor horse with 20 tooth¬ 
aches compressed into one agony. The leg is bent with diffi¬ 
culty and with pain, owing to the flexion of the perforans ten¬ 
don upon the navicular bone. The process of this disease is 
mostly inflammatory, followed by ulceration, necrosis, or ossifi¬ 
cation of the bones of the coffin joint. If the disease is of long 
