56 



Charles Reid 



(2) an outer fibrous ring, 3*5 cm. in diameter, 



(3) thin fibrous material covered by smooth endothehum, stretching 

 between the two rings and thickened by six or seven fibrous bands running 

 radially between the two circular fibrous rings. 



No other abnormality, developmental or acquired, was noted in the right 

 or left chambers of the heart. The interventricular septum did not appear to 

 be in any way abnormal, and the coronary veins both right and left were small. 

 They did not appear to be enlarged on either side of the heart. 



Lateral view of valve-Iike structure between cavity of left 

 ventricle above and cyst-like dilatation below. 



From its origin and course, this abnormal vessel was taken to be a left 

 coronary artery — the abnormality affecting more particularly the descending 

 branch of the left coronary artery. The dilatation of the terminal portion of 

 the vessel at the apex was difficult to explain. This dilatation might have been 

 due wholly to the developmental abnormality, or it might have been acquired 

 mainly. If the latter supposition was correct, the dilatation would have been 

 of the nature of an aneurismal dilatation. Support might be lent to this view 

 by the fact that, when the dilated portion was distended with water, it was 

 noted that at two or three places the wall was much thinned. The distension 

 might have been brought about by the escape of blood from the left ventricle 

 throughout the greater part of systole before the opening between the cavities 

 of the left ventricle and the dilated part was closed by the contraction of the 

 left ventricle towards the end of systole. 



Developmentally, no explanation of the abnormal coronary and com- 

 munication with the left ventricle has been suggested. 



