SALIVARY SECRETION. 



41 



fibers arise from a center in the medulla and proceed to the 

 glands by various routes; those to the submaxillary and sub- 

 lingual glands in the chorda tympani, and those to the partoid 

 by way of the tympanic branch of the glosso-pharyngeal. The 

 ganglion cells connected with the cerebral fibers are situated 

 more or less peripherally; in the case of the submaxillary 

 they are embedded in the substance of the gland ; in the case of 

 the sublingual gland, in the connective tissue of the so-called 

 submaxillary triangle, and in the case of the parotid, in the otic 

 ganglion (Fig. 3). 



In both cerebral and sympathetic nerves there are two vari- 

 eties of fibers, the one vasomotor, the other secretory. The for- 



Fig. 3. The nerve supply of the submaxillary gland : Li, lingual nerve ; 

 c. t., chorda tympani ; g. gland Wharton's duct is ligated and it will be 

 noticed that the chorda leaves the lingual nerve, just before this crosses the 

 duct, thus forming the submaxillary triangle. (Claude Bernard.) 



mer, in the case of the cerebral nerves, are dilator in their action, 

 but in the sympathetic they are constrictor. On account of the 

 association of secretory and vasodilator fibers, in the cerebral 

 nerves, stimulation leads to the secretion of large quantities of 

 saliva, the amount of which, as well as its percentage of organic 

 and inorganic constituents, varies within certain limits, with the 

 strength of the stimulus. Although secretory activities also be- 

 come excited when the sympathetic nerve is stimulated, as is 



