Joseph Marshall Flint 17 
tinues: ‘“* Mit dieser einen Thatsache fallt die ganze Aeby’sche Theorie 
von den ep- und hyparteriellen Bronchien ein- fiir allemal.” This view 
for which Narath has apparently received the entire credit in the litera- 
ture was, as we have already -seen, first announced by Willach. Na- 
rath’s single addition to Willach’s statement is in the designation of the 
eparterial branch as a dorsal element in conformity with his idea as to 
the possible derivation of the whole series of dorsal bronchi. In his 
belief, that the eparterial bronchus has the area of distribution of a dorsal 
bronchus, his observations are not in accord with those of Aeby, His, 
and Robinson. 
Minot, 92, thinks the ideas of Aeby and His are erroneous with ref- 
erence to the monopodial growth of the tree. He, on the other hand, 
looks upon the branching as characteristically dichotomous, describing 
the branches as having rounded ends. After division they develop un- 
equally with the ventral fork, as a rule, serving as the stem. The first 
branches correspond to the lobes, but he does not agree with the findings 
of His and Aeby with reference to the presence of a bronchus in the 
right lung which is not represented in the left. With Willach and 
Narath he regards the eparterial bronchus of the right side and the 
apical branch of the first ventral on the left as homologous. The dif- 
ference between the two, Minot holds, is due to the more precocious de- 
velopment of the right side and the secondary modifications in the arteries. 
The relationship of the veins confirms this view. The peculiar course 
of the right pulmonary artery is due to the abortion of the 5th arch on 
the right side and the subsequent transfer of the origin of the artery to 
the left. 
In a series of papers d’Hardiviller, 96, 1, 2,; 97, 1, 2, 3, describes in 
the rabbit and sheep, the evolution of the tree after the trachea and 
main bronchi are laid down. There is, according to this author, a stem 
bronchus which transverses the whole lung and from which all of the 
primary bronchi are derived by means of collateral ramifications, that 
is to say, through epithelial herniw from the walls of the stem bronchus, 
a process in which the terminal bud of the bronchus takes no part. In 
this way appear, in the rabbit, two buds on the right side and one on the 
left which, with the stem bronchi, enter into the formation of the five 
lobes of the lungs and produce all further ramifications. In the sheep, 
on the other hand, there are, including the stem bronchi, four buds on 
the right and two on the left giving rise to the six lobes of the sheep’s 
lungs. The primary branches of the stem bronchus occur in four series, 
external, internal, anterior, and posterior, according to their position 
2 
