i8 



QUATERCENTENARY STUDIES IN TATHOLOGY 



substance. The fibrous ring round the rest of the orifice has the same 

 structure as the mitral valve — fibrous tissue with the fibres lying in 

 parallel bundles, with cells arranged in definite lines between the fibres. 



Figure lo, heart of a man, aged 20, who died in the London Hospital from acute endo- 

 carditis. The left ventricle is opened and exposed. 

 (i) Aorta. 



(2) Infundibulum of right ventricle. 



(3) Anterior cusp of mitral valve. 



(4) Base of left ventricle ; between 4, 4, below the origin of the aorta is seen the 



fibrous endocardial ring, which I interpret as a remnant of the bulbus cordis. 



(5) Left ventricle. 



(6) Top of interventricular septum, below fibrous ring. 



(7) Mitral cusp of aorta, showing ulceration and vegetations. 



(8) Left auricle. 



(72) 



