110 O. LARSELL 
appear to constitute nodal poits from which the secondary 
and tertiary branches are given off. As in the case of the larger 
terminations found in the primary bronchi, some of the tertiary 
rami approach the surface of the epithelium, but others appear 
to end between the epithelial cells. All are characterized by 
small knobs at their tips. In thick sections of 504 to 75u, in 
which these terminations can be studied to best advantage, the 
greater number of terminal filaments appear to end between the 
cells of the epithelium. 
With this general description in mind, it will be of advantage 
to turn attention to the peculiarities of the terminations at the 
various orders of the bronchial branches. Figure 2 represents 
a sensory ending located at the point of division of a large 
bronchus. Comparison of this figure with figure 1, from the 
epithelium of the primary bronchus, will show many points of 
similarity between the two. The termination from the bifur- 
eating portion of the bronchus has the same characteristic type 
of ramification, its rami subdivide similarly, and in general 
have a similar appearance. The principal difference between 
the two consists in the smaller size of the termination from the 
smaller bronchial division. 
These endings in the larger bronchi appear to correspond 
with the terminations described and figured by Berkley (’93) as 
brought to view by the Golgi method of staining. Berkley also 
figured enlargements on the fibers leading to some of the nerve 
endings, and suggested that these might be nerve cells. Similar 
enlargements have been observed in the present study, but they 
appear to be unusually large varicosities rather than nerve cells. 
This conclusion is based on the fact that the enlargements in 
question are of considerably smaller size than any undoubted 
nerve cells encountered in the lung. Also no nucleus was 
observed in any of the enlargements of this type encountered, 
although the method of staining employed would ordinarily 
differentiate between the nucleus and the cytoplasm, while the 
Golgi method might not do so. 
A point of considerable interest in connection with the nerve 
terminations at the points of branching of the larger bronchi 
