16 C. W. M. Poynter 
(1857), Meyer (1857), Sturock (1859), Hervieux (1861), Rauchfuss 
(1864), Arnold (1868), Vulpian (1868), Semple (1870), Peacock for 
Royds (1870b), Peacock (1871), Peacock (1874), Heineman (1878), 
Crocker (1879), Schrotter & Chiari (1879), Luneau (1880), Stifel (1880), 
Cronk (1881), Turner (1883), Ashby (1884), Hayward (1884), Leo 
(1886), McKee (1887), Habershon (1888), Murray (1888), Northrup 
(1888), Bingham (1889), Wagner (1889), Griffith (1891), Moore (1892), 
Burgess (1893), Probyn-Williams (1894), Grothe (1898), Lowenthal 
(1900), Thomson & Drummond (1900), Champeter & Carton (1903), 
Schreiber (1903), Cohn (1904), McCrae (1906), Keith (1909), Hebb 
(1913), Milland (1914). ; 
C. Transposition of the Aorta and Pulmonary Artery 
Abnormal positions of the great vessels coming from the heart 
have generally been discussed under the head of “transposition 
of the aorta and pulmonary artery” and reported cases are gen- 
erally found in connection with accounts of congenitally defec- 
tive hearts. Transposition, like the conditions considered in the 
preceding sections, seems to bear a very close relation to cardiac 
development and is most frequently found in conjunction with 
defective septum ventriculare. 
It is not necessary to develop the subject in detail, for the 
work of Rokitansky (1875) still stands, in spite of recent contri- 
butions to the history of development, as the most lucid and com- 
plete discussion of the subject that has been made. Although the 
anomaly belongs in part developmentally to the heart, it is in- 
cluded in this study because it is generally reported as an ar- 
terial variation. In order to classify the types of the anomaly in 
harmony with recent discoveries it will be necessary to review 
the points of development and the theories advanced concerning 
the etiology of the condition. 
The more recent investigations have shown that the bulbus 
cordis of more primitive forms is represented in the mammalian 
heart, Greil (1903), early forming part of the anterior limb of 
the heart; then it is absorbed partly into what becomes later the 
right ventricle and partly into the truncus arteriosus. The elon- 
gated truncus arteriosus becomes differentiated into the aorta and 
pulmonary artery through the aortico-pulmonary septum, which 
244 
