47 6 



SALIVA. [CH. xxx. 



sublingual glands. Nicotine applied locally has the power of 

 paralysing nerve-cells, but not nerve-fibres. If the submaxillary 

 ganglion is painted with nicotine, and the nerve stimulated on the 

 central side of the ganglion, secretion from the submaxillary 

 gland continues, but that from the sublingual gland ceases. The 

 paralysed nerve-cells in the ganglion act as blocks to the propaga- 

 tion of the impulse, not to the submaxillary, but to the sublingual 

 gland. The cell station for the submaxillary fibres is in Langley's 

 ganglion. 



Parotid Gland. This gland also receives two sets of nerve- 



Fig. 398. Diagrammatic representation of the submaxillary gland of the dog with its 

 nerves and blood-vessels. (This is not intended to illustrate the exact anatomical 

 relations of the several structures.) sm. gld., the submaxillary gland into the duct 

 (sm. d.) of which a cannula has been tied. The sublingual gland and duct and 

 Langley's ganglion are not shown, n. L, n. I.', the lingual or gustatory nerve ; 

 ch. t., ch. t.', the chorda tympani proceeding from the facial nerve, becoming con- 

 joined with the lingual at n. I.', and afterwards diverging and passing to the gland 

 along the duct ; sm. gl., submaxillary ganglion with its roots ; n. I., the lingual 

 nerve proceeding to the tongue; a. car., the carotid artery, two branches of which, 

 a. sm. a. and r. sm. p. pass to the anterior and posterior parts of the gland ; v . sm., the 

 anterior and posterior veins from the gland ending in v.j., the jugular vein ; v. sym., 

 the conjoined vagus and sympathetic trunks ; gl. cer. s., the superior-cervical ganglion, 

 two branches of which forming a plexus, a. /., over the facial artery are distributed 

 (n. sym. sm.} along the two glandular arteries to the anterior and posterior portion of 

 the gland. The arrows indicate the direction taken by the nervous impulses ; during 

 reflex stimulations of the gland they ascend to the brain by the lingual and descend 

 by the chorda tympani. (M. Foster.) 



fibres analogous to those we have studied in connection with the 

 submaxillary gland. The principal secretory nerve-fibres are 

 glossopharyngeal in origin ; the sympathetic is mainly vaso- 

 constrictor, but in some animals does contain a few secretory 

 fibres also. 



