no Journal of Comparative Neurology. 



distant localities is possible, as they bear the same relation to 

 the nerve terminations of the bronchi as the endings of tactile 

 sensation do to their intermediate ganglionic cells, but their 

 structure is so hidden by the dense silver precipitate that it is 

 extremely difficult to decide if they are simply large varicosities 

 of the fibre, or actual ganglionic enlargements provided with a 

 nucleus and nucleolus. 



Neither of the methods of preparation give a distinct clue if 

 there are endings to the nerves upon the epithelium of the 

 alveoli. It is true that near some of the bronchi, fibres depart 

 from the main network surrounding the tube and artery, and 

 for short distances give off branches to the air cells lying just 

 along the edge of the tube, terminating near the pavement 

 epithelium in a small bulb; but scattered muscular fibres cannot 

 be definitely excluded from such situations, and it is quite pos- 

 sible that these endings are distributed to them. 



Intcr-alveolar fibres. Nerve fibres pass off from the 

 broncho-arterial network in the form of bundles or single fibres 

 and wander quite long distances in the septa between the air 

 cells. Many of them give off dichotomously numbers of side 

 branches, and all of them may either join the extensions of 

 other bronchial plexuses or may be distributed to the inter- 

 alveolar tissues, and also are occasionally seen supplying the 

 surfaces of the smallest bronchioles. Near the root and in the 

 mid-regions of the lung these inter-alveolar nerves are quite 

 frequent and from striking pictures [Fig. 4], from their coarse- 

 ness and prominence. Their final ending in the septa is in a 

 simple bulb like arrangement. 



Anterial Supply. The nerve supply to the bronchial arter- 

 ies is an exceedingly rich one, and is more extensively developed 

 than in any of the glandular organs, the ovary perhaps excepted. 

 Quite often, as in Fig. 5, the peri-arterial spaces are marked out 

 by lines of thicker nerve bundles, whose side branches anasto- 

 mose with the fibres of the arterial networks proper. End- 

 terminations are not so numerous as one would expect from the 

 extreme closeness of the network, yet they are quite frequent, 

 always arising as short branches from the plexus and ending as 



