RUPTURE OF THE PULMONARY ARTERY. 367 



About three in the afternoon of the 2nd March, 1895, it was playing 

 with another dog in front of its master's house, when suddenly it began 

 running as though mad, leaped upwards several times, and fell dead. 

 Poisoning being suspected, the cadaver was sent to the College. 



Autopsy. — Extreme pallor of the visible mucous membranes. The 

 spleen was large, and of the lilac tint common in lymphadenoma. The 

 liver had undergone a certain degree of hypertrophy. 



Lungs normal. The pericardium was considerably distended with 

 blood. The organs about the base of the heart, the large vessels 

 originating there, and the trachea, were covered with a layer of coagu- 

 lated blood, infiltrated between the layers of the mediastinum. 



On opening the pericardium a little red blood escaped. The cavity 

 contained a thick clot moulded on the heart. Over the origin of the 

 great arterial vessels the visceral layer presented a rupture about three 

 eighths of an inch in length. 



The heart was carefully examined, but neither ventricles, auricles, 

 nor valves showed anything abnormal. 



The external surface of the pulmonary artery was covered with a 

 thick clot. On removing this we detected on the right surface of the 

 vessel, about three eighths of an inch from the base of the heart, two 

 transverse ruptures, one measuring a quarter of an inch, the other one 

 eighth of an inch in length. Opposite these tears the artery was ex- 

 tremely thin, and showed several little atheromatous points. Escaping 

 by these ruptures the blood had spread around the large vessels, thrust 

 apart the layers of the mediastinum, lifted the visceral layer of the 

 pericardium, which became ruptured under the pressure, and then by 

 accumulating in the pericardial sac produced cardiac syncope and 

 death. 



