118 The Development of the Lungs 
gethan, zwischen dem eparteriellen und hyparteriellen Bronchialgebiet 
unterscheidet.” 
Aeby looked upon this apical branch of the 1st lateral on the left side 
as a simple side branch, which extends up into the apex of the lung 
having a certain outward similarity to Lateral 1, which might, he point- 
edly remarks, lead to erroneous assumptions. This branch was named by 
His, the Bronchus ascendens, an element, which substitutes in the left 
lung for the unpaired eparterial bronchus in the right, a view in which 
he is supported by Robinson. Narath and Willach, on the other hand, 
as stated above, look upon it as the equivalent of the eparterial bronchus, 
a homology which is affirmed by Minot, Huntington, Merkel, and Blis- 
nianskaja, but d’Hardiviller, and Nicholas and Dimitrova accept the 
conclusions of Aeby, His, and Robinson. That is to say, d’Hardiviller 
accepts them in so far as they regard the left apical bronchus of Narath, 
a true side branch of the 2d lateral trunk and not the equivalent of the 
eparterial bronchus on the right side. 
In following, step by step, the appearance of the secondary divisions 
of Lateral 2, in the pig, we find on the right side the dorsal fork is 
turned downwards and outwards owing to the presence of Lateral 1 
above it, in consequence of which, it becomes the large dorsoinferior branch 
of L. 2. On the right side, however, this unobstructed branch extends 
upwards toward the apex of the lung and substitutes, as Aeby-and His 
pointed out, for the suppression of left L. 1. It is, however, a true side 
branch of Lateral 2 and is not to be regarded as the homologue of right 
Lateral 1, which in the vast majority of cases is unpaired. 
LATERAL BRONCHI. 
Kolliker, who worked on the rabbit, agrees with the observations of 
Remak on the chick in finding the first branches of the stem bronchus 
growing lateralwards and dorsalwards. He did not, however, give the 
lateral group a special name. Aeby, whose observations were made upon 
full-grown material, designated them ventral bronchi in contradistine- 
tion to the dorsal group, both of which arise in the hyparterial region 
from independent origins, while in the eparterial region the dorso- 
ventral bronchus uninfluenced by the pulmonary artery has a common 
origin from a point on the stem bronchus or trachea midway between the 
origin of the dorsal and ventral bronchi in the hyparterial group. Al- 
though His would have preferred the term lateral bronchi, he follows the 
description of Aeby, while Robinson is really the first to take his term 
lateral bronchi from the topography of the embryonic lung. Zumstein 
