INNERVATION OF THE DIGESTIVE TUBE 181 



plicae and the intestinal villi where many of them terminate on 

 cells of the digestive epithelium. Such fibers are illustrated in 

 the accompanying figure (fig. 2, C, ft) which is taken from a 

 section through the cardiac region of the stomach of the cat 

 prepared by the methylene blue method. 



The ganglia of the submucous plexus show a wider range in 

 size and form than do the ganglia of the myenteric plexus. The 

 latter, being interposed between the longitudinal and the circular 

 muscle-layers, are more or less regular in form. The ganglia of 

 the submucous plexus, on the other hand, are surrounded by 

 loose connective tissue which apparently exercises little influence 

 in determining their form. Some of these ganglia appear as 

 small rounded or elongated cell-groups. Others are more or less 

 irregular in form or even T- or Y-shaped according to the angles 

 between the commissures which radiate from them. These gan- 

 glia may be relatively small, containing relatively few neurones, 

 or relatively large, containing relatively many neurones. In all 

 of them, however, the neurones are more compactly aggregated 

 than are the neurones in the ganglia of the myenteric plexus. It 

 becomes correspondingly more difficult, therefore, to trace out 

 the processes of these cells. In sections of material successfully 

 prepared by the pyridine-silver method taken in the plane of the 

 plexus, however, this may be done quite satisfactorily. In good 

 preparations of this kind little tissue appears in these ganglia 

 except the fibers which pass through them at various angles and 

 the neurones with their processes. In these ganglia also, as 

 Miiller ('11) has suggested, pericellular capsules are probably 

 not present. 



The neurones in the ganglia of the submucous plexus present 

 quite as wide a range of variation in size and form as do the 

 neurones in the ganglia of the myenteric plexus. They possess 

 certain distinctive characters, however, by which the experienced 

 observer may without difficulty recognize them as belonging to 

 the submucous plexus. They are also relatively smaller than the 

 neurones in the myenteric plexus. A few of these neurones taken 

 from pyridine-silver preparations of the small intestine of the 

 dog are illustrated in figure 1, D, E, F. 



THE JOURNAL OF COMPARATIVE NEUROLOQY, VOL. 23, NO. 3 



