574 CHEONIC DISEASES OF THE HEART. 



and Disease,' states Avith regard to these lesions, that their 

 usual situation in the horse is at the conus arteriosus of the 

 left ventricle, where the tendinous ring uniting the gi-eat 

 aorta with the ventricle is the structure which is found to 

 have ruptured. The only cases of this lesion which I have 

 encountered were in this particular situation ; both were aged 

 animals, previously in the full enjoyment of health and apparent 

 vigour ; nor after death could I on examination detect any 

 structural changes at the seat of rupture, which we might have 

 anticipated would have led to this. 



In both animals death occurred immediately after a short 

 but sharp drive ; they were placed in the stable apparently 

 well, and shortly afterwards were found dead. 



As illustrative of the fact that violence applied to the chest- 

 wall may cause rupture of the heart, there is quoted by Mr. 

 Gamgee a case reported in the Veterinarian by Mr, Parker of 

 Birmingham, where a pony, in running away with a gig down 

 a hill, came violently in contact with the wheel of a cart, 

 striking it with his right shoulder. The animal came to the 

 ground, from which he was never able to rise, and was shortly 

 afterwards destroyed. On being examined after death the 

 pericardium was found ruptured on the right side, and con- 

 tained a quantity of coagulated blood ; there was also a blood- 

 clot attached to the base of the right auricle, which was here 

 separated from the ventricle. The ribs and investing muscles 

 were uninjured. 



I have also, on one occasion, observed rupture of another 

 portion of the heart-structure, which is probably not at all 

 common, and which, in the instance referred to, was associated 

 with suppurative disease of the true muscular structure. The 

 rupture was that of one of the fleshy pillars of the ventricle 

 and of some of the tendinous cords attached to it. This was 

 in the case of the foal already mentioned as affected with 

 myocarditis associated with pyi^emia. The integrity of the 

 fleshy pillar seemed impaired by the progress of the contiguous 

 inflammatory action. 



In anatomical characters there may be some differences 

 both of situation and form of rupture, which will have an im- 

 portant bearing upon the suddenness with which a fatal 

 termination is reached. 



