XX.— AORTIC INSUFFICIENCY IN THE HORSE. 



To-day we saw in the clinique a horse with very well-marked 

 aortic insufficiency, and I mentioned to you in some detail the pecu- 

 liarities shown by the animal. I have had opportunities of seeing a 

 very considerable number of similar cases. To-day I intend to treat 

 of this condition, and while describing certain cases, to point out the 

 diagnostic symptoms. 



In the horse aortic insufficiency is by far the most frequent of all 

 heart diseases. It may be seen in animals of all ages, without distinc- 

 tion of sex or breed, though the majority of published cases refer to 

 old animals slaughtered for experimental or anatomical purposes. In 

 animals of this class M. Nocard and I found thirty-eight aortic and 

 four associated aortic and mitral lesions in a total of forty-two cases. 



Aortic insufficiency sometimes forms an isolated lesion, sometimes 

 an accompaniment of other lesions of the endocardium, or of arterial 

 atheroma. In man, where the latter condition is very common, aortic 

 insufficiency of cardiac origin, consecutive to endocarditis, is distin- 

 guished from insufficiency of arterial origin associated with sclerosis 

 of the arteries. In the horse valvular lesions are sometimes accom- 

 panied by atheroma of the aorta, but very generally atheroma is absent, 

 and the valvular disease simple, or only combined with other valvular 

 changes. 



With very rare exceptions, it results from some infectious process, 

 during which the endocardium has been injured by blood-borne micro- 

 organisms, or their toxins. It may also follow acute inflammation of 

 the lung, especially the contagious form, and the typhoid form of 

 influenza. Rheumatism, which, as you know, is rare in the horse, also 

 appears to produce it. In human medicine it has long been known 

 that rheumatic lesions appear to have a decided predilection for the 

 endocardium, etc., which they permanently affect. " Rheumatism," 

 said a celebrated clinician, "licks the joints, the pleura, and even the 

 meninges, but it gnaws the heart." 



Whatever the determining cause, inflammation of the semilunar 

 valves soon assumes a chronic character, and determines a series of 



