CH. XXXII.] SECRETORY NERVES OF SALIVARY GLANDS 



503 



that the many theories formerly advanced of the relative part 

 played by the two nerves must be regarded as mere matters of 

 speculation. 



Section of the chorda tympani produces no immediate result ; but after a few 

 days a scanty but continuous secretion of thin watery saliva takes place ; this is 

 called paralytic secretion. If the operation is performed on one side, the gland of 

 the opposite side also shows a similar condition, and the thin saliva secreted 

 there is called the antUytic secretion. The meaning of these phenomena is 

 unknown. 



Effect of drugs on the gland. Atropine. After intravenous injec- 

 tion of this alkaloid stimulation of the chorda tympani no longer 

 produces secretion of saliva. Much 

 larger doses are necessary to abolish 

 the vaso -dilator effect of chorda stimu- 

 lation, or the sympathetic flow in those 

 cases where previous stimulation of 

 this nerve evoked a secretion of 

 saliva. 



Pilocarpine produces a copious 

 flow of saliva, accompanied by vaso- 

 dilatation. 



Ergotoxine paralyses the effects of 

 sympathetic stimulation, but not 

 those of stimulation of the chorda 

 tympani. 



Adrenaline produces constriction 

 of the blood-vessels. In some animals 

 it evokes a considerable flow of saliva, 

 and when this occurs the constriction 

 of the vessels is followed by dilatation. 

 This favours a view which has been 

 advanced by some observers, that 

 vaso-dilatation is in part produced by 

 the chemical action of the products 

 of activity (carbonic and lactic acids, etc.). 



The sublingual gland is innervated by the same nerves 

 as the submaxillary, but the preganglionic fibres of the chorda 

 tympani have their cell-station in the so-called submaxillary ganglion 

 which is situated close to the sublingual gland (see fig. 353). The 

 submaxillary ganglion ought properly to be termed the sublingual 

 ganglion. This has been determined by Langley's nicotine method 

 (see p. 200). 



The parotid gland also receives two sets of nerve-fibres analogous 

 to those we have studied in connection with the submaxillary gland. 

 The principal secretory nerve-fibres are glosso-pharyngeal in origin ; 



FIG. 353. Diagram of secretory nerves of 

 submaxillary and sublingual glands. 

 Two fibres of the chorda tympani (Ch.) 

 are shown, one of which supplies the 

 sublingual gland, of which an acinus is 

 shown ; "the cell-station for this is in S. 

 G., the so-called submaxillary ganglion. 

 The other fibre supplies an acinus of the 

 submaxillary gland ; its cell-station is in 

 Langley's ganglion (L. G.), within the 

 substance of the gland. Sy. is a fibre of 

 the sympathetic, which has its cell- 

 station in the superior cervical ganglion, 

 S. C. G. (Alter Dixon.) 



