he cause of the condition to be
due to sclerastomiasis.]

The seizures are accompanied with profuse sudation, tremors,
dilated nostrils, accelerated respirations and other symptoms of
pain and distress, all of which, together with the lameness,
disappear as rapidly as they had developed, leaving the animal in
an apparently perfect state of health, ready to fall with another
attack of precisely the same kind, as soon as enough exercise is
forced upon it. The rectal explorations may reveal a pulseless
state of one or more of the iliac arteries and a hardness and
enlargement of the aortic quadrifurcation, but sometimes this
palpation fails to disclose any _perceptible_ diminution of the
blood current of these vessels. The obturation being incomplete, it
may be impossible by palpation to decide that thrombosis really
exists. In this event and, in fact, in all eases, the clinical
symptoms are sufficiently characteristic to make a diagnosis
without reservation. It cannot be mistaken for any other disease,
once properly investigated. Any given seizure may easily be
mistaken for azoturia, at first, but a better examination soon
excludes that disease.

[Illustration: Fig. 49--Illustrative of thrombosis of the aorta, iliacs
and branches. Photo by Dr. L.A. Merillat.]

Prognosis and Treatment.--In the majority of instances, when
there is occasioned serious inconvenience, the outcome is not
likely to be favorable, according to Moeller. Detachment of a
portion of the thrombus, according to Hoare, may result in the
lodgment of an embolus in the brain or kidneys. The latter
authority also states that muscular atrophy may occur owing to lack
of blood supply in some of these cases. Moeller states that
moderate exercise or work stimulates the establishment of
collateral circulation. Massage per rectum is condemned as
dangerous by Cadiot.

Fracture of the Patella.

Etiology and Occurrence.--Patellar fractures are rarely met with in
the horse but may be caused by falls and heavy contusions. Violent
muscular contraction, it is said, may also bring about the same
condition.

Symptomatology.--Fracture may be transverse or vertical, and depending
on the manner in which the bone is broken, prognosis is either at once
rendered favorable or unfavorable. The patella performs a function which
is in a