NERVE TERMINATIONS IN LUNG OF RABBIT fly 
conclusion is based on a detailed comparison of such fibers, as 
demonstrated in methylene-blue and silver preparations of the 
lung, with the elastic fiber network brought to view by the 
specific elastic fiber stains, such as orcein and resorcin-fuchsin. 
Undoubted nerve fibers elsewhere in the lung, even those of the 
smallest size, have a different appearance from the fibers under 
consideration. The difference consists in the much darker stain 
which the nerve fibers take and in the fact that the latter always 
present varicosities and have a much more irregular course than 
do elastic fibers. 
A reexamination of my preparations after reading Ponzio’s 
article, and a comparison of his figures with the fibers in these 
preparations, has strengthened the conclusions already reached. 
namely, that the network of delicate fibers in the walls of the 
air sacs is composed of elastic fibers. Ponzio’s figure 9 should 
have separate comment and will be referred to again in connection 
with the innervation of the pulmonary blood-vessels. 
There appears little room for doubt that the several termina- 
tions described are of sensory type. Their position in the epi- 
thelium, particularly at the points which appear most subject 
to irritation, their connection with the relatively large, myeli- 
nated nerve fibers, and the character of their terminal arboriza- 
tions, appear to point to the conclusion that they are sensory 
rather than motor. The present writer has not attempted any 
experimental studies to test these conclusions, but the results 
_ obtained by Molhant (713), who studied the distribution of the 
sensory fibers of the vagus nerve in the rabbit, agree very well 
with the interpretation expressed. 
Molhant extirpated the superior and median lobes of the right 
lung in the rabbit, and after allowing time for the injury of the 
nerve fibers involved in the trauma to affect the cells of origin 
of these fibers, he stained the peripheral ganglia of the vagus 
by the Nissl method. He found that ganglionic cells in the 
external portions of the median and inferior segments of the 
ganglion nodosum showed the typical degeneration of the Nissl 
granules as a result of the injury suffered by their peripheral 
processes. Molhant concluded that the cells thus affected 
