Joseph Marshall Flint ft 
Dichotomie nur ein gradueller, aber kein wesentlicher Unterschied, und 
es wiirde daher kein Erstaunen hervorrufen diirfen, wenn in der Archi- 
tektur des Bronchialbaumes sowohl die eine wie die andere Weise zur 
Anwendung gekommen ist.” 
If we attempt to tabulate these views on the growth of the bronchial 
tree, the results may be placed in three main divisions as follows: 
1. Dichotomy. Older authors, Ewart, Minot, Justesen, Blismianskaja. 
2. Monopody. Kiittner, Cadiat, Kolliker, Aeby, Nicholas and Dimi- 
trova, Willach, Narath, Moser. 
3. Monopody and Dichotomy. Stieda, His, Robinson, Huntington, 
d’Hardiviller, Hesser, Flint. 
It is also possible to subdivide them still further in the following way: 
1. Dichotomy. Older authors, Ewart, Justesen, Minot. 
2. Unequal Dichotomy. Robinson (?), Blisnianskaja. 
3. Monopody. Aeby, Moser. 
4. Monopody with participation of the end bud. Willach, Narath, 
Nicholas, and Dimitrova. 
5. Mixed Monopody and Dichotomy simultaneously. Stieda, Robin- 
son. 
6. Monopody and Dichotomy successively. His, @’Hardiviller, Hunt- 
ington, Hesser, Flint. 
While we have already called attention to those who have only studied 
the branching from the finished tree, to which class belong Aeby, Ewart, 
and Huntington, there is still a group, in the series of authors given 
above, who have not followed the lungs through the development of the 
stem and its chief branches in mammals, that is to say, their material 
consisted of embryonic stages after the formation of the principal bronchi 
was complete. The observations of these investigators are only import- 
ant for the specific fields in which they worked, for it goes without say- 
ing, as His has suggestively remarked, the conditions which govern the 
form development of a growing part need not necessarily remain the 
same through the different phases of its evolution. It may change its 
character either once or more than once. 
Thus for a series of animals covering amphibia, reptilia, birds (Moser, 
Hesser, Schmalhausen), man (His), rats and mice (Robinson), mouse, 
mole (Willach), rabbit (d’Hardiviller), sheep (Nicholas and Dimitrova), 
rabbit, Echidna, cat (Narath), pig (Flint), we have a general agree- 
ment, that the stem and its principal branches are produced by mono- 
podial growth. I have placed Robinson in this group, partly because 
he believes some of the chief branches are monopodial in nature, but 
largely because, notwithstanding his own use of the term “sympodial 
