234 ON ANEURISM OF THE AORTA IN THE HORSE. 
The Editor of ^‘The Veterinarian'' gave, in the early 
part of this spring, a scruple of the farina of the croton seed to 
a horse, on vv^hom six. drachms of aloes, administered two days 
before, had not operated. The animal died from superpurga¬ 
tion. To another horse, to whom it was almost impossible to 
administer a ball, the same quantity wis given in a mash. It 
purged briskly; but the patient underwent a severe salivation. 
Edit. 
ON ANEURISM OF THE AORTA IN THE HORSE. 
f 
By T. 
« 
NONE of our veterinary writers have given us any account 
of the symptoms and progress of aneurism of the aorta in the 
horse. 
• Mr.‘Blaine accidentally saw a case of rupture of the anterior 
aorta. The horse was proceeding slowly, and apparently in 
perfect health, and suddenly dropped and died. Mr. Percivall 
describes a specimen of aneurism of the thoracic aorta; but no¬ 
thing was known of the previous history of the animal. 
* A true aneurism is a dilatation of an artery, either in a small 
part of its course, and then called a circumscribed true aneurism, 
or for a considerable length, and then teraied a diffused true 
aneurism. 
These dilatations are confined principally to the pulmonary, 
the coeliac, and the mesenteric arteries; and mostly, in old sub¬ 
jects, the coats of the artery are unnaturally thin. 
A false aneurism has been said to be when the blood has 
escaped from a wound in the artery into the surrounding cellular 
substance. A cyst is then formed, constituting a circumscribed 
tumour. 
I would rather say that the false aneurism either surrounds 
the artery, and communicates with it during its whole extent, 
or is attached to one of its sides, generally the inferior face, and 
sometimes merely by a pedicle at thepoint where the aneurismal 
pouch opens into the cavity of the artery. These pouches or 
tumours usually appear to be formed by an extraordinary dis¬ 
tension of all the tunics of the artery. Instead of being rup¬ 
tured by the pressure of the blood, they yield to an incon¬ 
ceivable extent. But these coats, although distinctly to be 
traced, have generally undergone mRch alteration. The middle 
coat is converted' into an osseous substance, which is covered 
