ON ANEURISM OF THE AORTA IN THE HORSE. 237 
was distended with blood. It was coagulated, and had 
adapted itself to the shape of the heart, so as to present the 
exact appearance of hypertrophy of the heart. A small rupture 
was found at the base of the trunk of the aorta, which was 
evidently owing to the remarkable thinness of the parietes of 
the artery at that spot. On opening the ventricular cavity, 
only one of the columns which traverse it from side to side was 
found, and that was as large as a quill, and entirely muscular. 
‘ M. Vatel remarks, that this case is principally valuable, 
because the mare did not, during life, exhibit a single symptom 
which could indicate the existence of the aneurism. . 
M. Rigot, anatomical professor at Alfort (Journal de Med. 
Vet. July 1827), says, that an old horse was bled to death at 
Alfort. On dissectino' him a false aneurism of the aorta and 
^ O 
anterior mesenteric arteiy was found. It was eight inches long 
and four wide, the parietes were bony, and it contained a fibrons 
clot of considerable consisten'ce. There seemed to be in this 
horse an aneurismal diathesis; for the pulmonary artery was 
evidently dilated, and likewise the carotids at the point of their 
division into three branches. There was no symptom in the 
living animal by which the existence of the aneurism could have 
been indicated. 
Of the cause of these aneurisms we can say but little. 
Something may be attributed to the thickness and power of 
the parietes of the left ventricle; the cuiwed direction of the 
arteries ; their proximity to the heart sustaining the whole force 
of the rush of the blood; the inequality betw^een the capacity 
of the large arteries, and the strength of their coats; any sudden 
increase of the arterial circulation; undue or long continued 
muscular efforts, and many other circumstances which wall 
immediately occur to the reader. 
It w^ould appear, on the wRole, that no symptoms will 
indicate the existence of aneurism ; or, should the aneurism be 
suspected, no medical treatment will remove it. If surgeons 
wall carefully attend to the post-mortem appearances in cases 
of sudden death, aneurism of the aorta may be found of more 
frequent occiuTence than is imagined. 
