Arterial Anomalies Be 
and those associated with inversion of the heart. He offered a 
substitute classification which is in many respects less satisfactory 
than the one criticized. Krause (1868) added many cases to 
those reported by Turner and presented a somewhat different ar- 
rangement of them. 
A review of all that has been offered in the literature concern- 
ing the proper arrangement of the abnormalities under considera- 
tion tends to impress one with the fact that no single classification 
will meet all requirements. I do not offer this arrangement as 
an improvement on what has gone before, but as the simplest 
method of presenting the material collected. A few cases in 
which there is marked disagreement from the explanation of the 
monographs cited above will be discussed, but minor differences 
will not be referred to, because of lack of space and not because 
they have been overlooked. 
A. Persistence of One or Both Pulmonary Arches 
, Abnormalities in the development of the pulmonary arches are 
rare, except the condition of persistence of the ductus arteriosus. 
This may be accounted for by supposing that this arch develops 
after the factors which produce the anomalies we have been con- 
sidering have ceased to be operative. Bremer (1908) has shown 
that the truncus pulmonis absorbs a part of the pulmonary arches, 
so that the left pulmonary artery springs from the truncus while 
the right pulmonary artery represents in its proximal portion a 
part of the right pulmonary arch. This point should be kept in 
mind in interpreting cases of absence of the aortico-pulmonary 
septum like that of Clarke (1885). 
Persistence of both pulmonary arches is very rare; the only 
cases with which I am familiar are those of Breschet (1826) and 
Peacock (1868). In the former the aortic arch was normal, the 
common pulmonary artery short and from its left branch the 
ductus arteriosus extended in the usual way. From the right 
branch of the pulmonary artery a slender artery extended upward 
to the right, joining the subclavian artery in its proximal portion. 
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