SECRETION. 



159 



mucous types are found imbedded iu the mucous membrane of the mouth and 

 tongue. The secretions of these glands contribute to the formation of the 

 saliva. 



The course of the nerve-fibres supplying the large salivary glands is interest- 

 ing in view of the physiological results of their stimulation. The description 

 here given applies especially to their arrangement in the dog. The parotid gland 

 receives its fibres from two sources first, cerebral fibres which originate in the 

 glosso-pharyngeal or ninth cranial nerve, pass into a branch of this nerve known 

 as the tympanic branch or nerve of Jacobson, thence to the small superficial 

 petrosal nerve, through which they reach the otic ganglion. From this gan- 

 glion they pass by way of the auriculo-temporal branch of the inferior max- 



Inferior maxillary 

 branch of fifth 



Otic 



\j ganglion 



Small superficial 



petrosal nerve 



Glosso-pharyngeal 

 nerve 



Petrous 

 ganglion 



FIG. 68. Schematic representation of the course of the cerebral fibres to the parotid gland. 



illary division of the fifth cranial nerve to the parotid gland. (A schematic 

 diagram showing the course of these fibres is given in Figure 68.) A second 



L, Facial 



Inferior maxillary 

 branch of fifth 



Branches to submaxil 

 lary and sublingual 



FIG. 69. Schematic representation of the course of the chorda tympani nerve to the submaxillary gland. 



Sublingual 

 ganglion 



supply of nerve-fibres is obtained from the cervical sympathetic nerve, the 

 fibres reaching the gland ultimately in the coats of the blood-vessels. The 



