38 C. W. M. Poynter 



2. Stenosis of the ascending trunk: Parker (1847), Dittrich (1849), de 

 Bary (1846), Maier (1876), Peacock (1877), Gefifrier (1881), Holt (1883), 

 Ziegenspeck (1888), Eppinger (1889), KHpstein (1889), Preisz (1890) 3 

 cases, Lamouroux (1899), Cautley (1908), Wenner (1909) 3 cases. 



B. Atresia of the Aortic Arch 



These cases do not belong with a study of the heart, but are 

 presented here because they are frequently encountered with con- 

 genital heart disease and act physiologically just as the preceding 

 group. The condition consists of the complete or partial oblit- 

 eration of the aorta just above the opening of the ductus arte- 

 riosus, so that the descending aorta receives its blood from the 

 pulmonary artery through the persistent ductus. 



Two groups of cases must be recognized. In the first the left 

 subclavian artery arises normally and the anomaly consists of 

 the obliteration of the dorsal root of the left fourth arch and the 

 persistence of the left pulmonary arch. In the second group the 

 left subclavian artery springs from the juncture of the ductus 

 and the descending aorta, and the anomaly is an obliteration of 

 the fourth left arch and dorsal root and the persistence of the 

 left pulmonary arch. 



Cases showing a constriction in the region of the fourth arch 

 and dorsal root have been reported by Valenti & Pisenti (1896), 

 Lewis (1903) and Pansch (1905). The condition of atresia 

 may occur without cardiac anomalies, but even so, no case lived 

 longer than 9 months and dyspnoea and cyanosis were frequently 

 observed ; cases studied as follows : 



Gibert (1832), Greig (1852), Schilling (1857), Smith (i860), Cameron 

 (1871), Barlow (1876), Osier (1880), Potocki (1886), de Renzi (1889). 



§ XIII. 



VIII. ABNORMALITIES OF THE SEMILUNAR 

 VALVES 



These conditions were recognized by the earlier observers, but 

 attracted very little interest ; later, when the development of the 

 valve became better understood, more attention was given to the 

 subject. 



