420 ANEUKISM. 



especially in deep-seated arteries. The posterior aorta, at 

 the origin of the anterior mesenteric artery, is very subject 

 to aneurism as animals grow old. Some remarkable cases 

 are reported in journals. I may quote a few instances 

 referred to by Mr Percivall in his Hippo-Pathology : 



" ANEURISM OP THE AORTA. 



" Although aneurism is by no means an uncommon disease in our 

 own bodies, in horses it is comparatively rare; so rare, that it scarcely 

 has become an object of veterinary practice. Nevertheless, as extra- 

 ordinary occurrences, accounts of cases must be at all times interesting 

 to the veterinarian, and as such I give those that have come under my 

 own observation, together with some others, of which there are several 

 to be found scattered through the pages of The Veterinarian. 



" The first I shall notice is a dried preparation belonging to my 

 father's museum, at Woolwich, a very fine specimen of aneurism of the 

 thoracic aorta. In shape, and indeed in magnitude, it may well be 

 compared to a gourd of ordinary growth. Through the bottom of the 

 aneurismal sac are two large circular apertures, where, evidently, it had 

 burst into the cavity of the chest. In several places the sac is much 

 attenuated, and appears as far as one can judge in its dried state to 

 have been in an ulcerated condition at the time of death. Whether 

 the sac is formed of the dilated or augumented coats of the vessel, or 

 is composed of adventitious coatings, it seems impossible, correctly, to 

 determine: its appearance most favours the latter supposition. No 

 other history attaches to the preparation than that ' it was brought 

 from the slaughter-house.' 



" Mr Field has, in his museum in London, a preparation of the same 

 kind as the one described above, and in most respects very similar 

 to it. 



"Mr Bowles, V.S., Blanavon, in 1841, sent Mr Morton, of the Eoyal 

 Veterinary College, a specimen of ossified aneurism of the posterior 

 aorta, a little anterior to the first lumbar vertebra, taken from a mare 

 that died of ruptured spleen. 



" Hen Bbhling (or Rohling), from four cases he relates of aneurism, 

 comes to the following conclusions: Aneurism of the large arteries, in 

 any of the cavities, particularly the aorta or mesenteric, may be ascer- 

 tained by certain signs, through which a sure diagnosis may be estab- 

 lished. The surest of these signs is the pulsation of the parts. Besides 



