10 ' QUATERCENTENARY STUDIES IN PATHOLOGY 



rugated, like the bulbus of fishes ; the lower orifice may be marked, as in 

 the case shown, by a fibrous diaphragm, muscular in structure at its 

 circumference. The muscular walls are extremely thick, as if the proper 

 amount of muscle had been provided for a fully expanded infundibulum. 

 The pulmonary orifice may be constricted ; the valves may be free but 

 are commonly imperfectly separated. A wide interventricular orifice is 

 commonly present, and death usually occurs before twenty. Death is 



Figure 4, heart of a girl aged 7 years. The right ventricle has been opened by a triradiate 

 incision. 



(i) Pulmonary artery (narrow, thin- walled). 



(2) Aorta (large). 



(3) Infundibulum below adherent pulmonary valves. 



(4) (5) Orifice of infundibulum ; below orifice is a large interventricular foramen. 



(6) Body of right ventricle. 



(7) Tricuspid valve. 



(8) Left ventricle. 



(9) Right auricle. 



frequently caused by an attack of bronchitis or of pneumonia, and in the 

 majority of cases recent vegetations are found round the fibrous margin 

 of the orifice. It is the occurrence of these vegetations which has 

 induced so many clinicians to accept endocarditis as the cause of the 

 entire condition ; it is evident that no endocardial lesion could produce 



(64) 



