io8 Journal of Comparative Neurology. 



ferences in appearance from those distributed to the viscera of 

 the abdominal cavity in a tendency to a more general fascicular 

 arrangement of the nerves, and also to a greater inclination than 

 is usually seen in glands to a racemiferous development of the 

 bronchial terminations, both in the mucous membrane and non- 

 striated muscular layers. The likeness to the nerve distribution 

 of the layers of the small intestine is superficially striking, but 

 close analogies are not apparent. The nerves themselves are 

 of two varieties, an extremely fine fibre accompanying both the 

 vessels and air-channels ; and a much coarser thread, usually in 

 pairs or bundles, also following the vessels and bronchi, but at 

 times departing from them, and wandering off among the sur- 

 rounding tissues. As the Golgi method does not allow of a 

 distinction being made between meduUated and non-meduUated 

 fibres, no conclusions can be drawn as to whether the coarse 

 fibres are meduUated, and the finer, especially the arterial plex- 

 uses, non-medullated, nevertheless it is reasonable to suppose 

 that some of the coarser fibres are provided with a myeline 

 sheath, as like fibres have been frequently seen by the older 

 observers running with the air-tubes. Ganglion cells are stained 

 somewhat sparingly by the silver, a few bipolar cells situated 

 near the bronchi have been found, but they bear no proportion 

 to those made apparent by other methods. Generally speak- 

 ing, nerves are most numerously stained near the root of the 

 lung, and gradually diminish in numbers toward the free mar- 

 gins. 



Nerves of the Bronchi. — In the external fibrous layer of 

 each bronchus is situated a considerable plexus of fine nerve 

 fibres, with at the outer margin an occasional coarser tube, or 

 small bundle ; all connected together by frequent ramuscules. 

 From this peri-bronchial plexus very numerous stems come off 

 that have a two-fold destination : [i], they are distributed upon 

 the cells of the smooth muscular layer, and show at many 

 points simple end-knob terminations, usually in rounded, less 

 frequently elongated shape. More rarely a fibre will come off 

 from the parent marginal plexus, and after giving off a few side 

 branches, will end in a very complex figure [Fig. i], but all the 



