THE SALIVAEY GLANDS. 1 



By J. K LANGLEY. 



CONTENTS : Anatomical Characters, p. 475 Histological Characters, p. 477 Origin 

 and Course of Nerves, p. 479 Changes during Secretion, p. 485 Reflex Secre- 

 tion, p. 489 The Dyspnoeic Secretion, p. 493 Stimulation of the Cranial 

 Nerve, p. 493 Stimulation of the Sympathetic Nerve ; the Augmented Secre- 

 tion, p. 494 Effect of Protracted Stimulation on the Amount and Percentage 

 Composition of Saliva, p. 498 Relation of the Rate of Secretion to the Per- 

 centage Composition of Saliva, p. 499 Some General Characters of Saliva, p. 501 

 Substances secreted in Saliva, p. 503 Effects of the Cranial and Sympathetic 

 Nerves upon the Blood Flow, p. 504 Mutual Effects of the Cranial and Sym- 

 pathetic Nerves upon Secretion, p. 506 Effect of Variations in the Amount 

 and Quality of the Blood supplied to a Gland, p. 508 Relation of Secretion to 

 the Flow of Lymph, p. 510 The Secretory Pressure, p. 511 Reflex Inhibition 

 of Saliva, p. 512 The Action of Alkaloids, p. 512 Formation of Heat, p. 516 

 Electrical Changes, p. 517 Section of Glandular Nerves ; the Paralytic 

 Secretion, p. 519 Secretion due to Reflex Action of Peripheral Ganglia, p. 523 

 Direct Irritability of Gland-Cells, p. 524 Extirpation of the Glands ; injec- 

 tion into the Blood of Saliva and of Gland Extracts, p. 524 General Con- 

 siderations ; theories of the Mode of Action of Secretory Nerves, p. 525. 



SOME ANATOMICAL CHARACTERS OF THE SALIVARY GLANDS. 



IN the dog and cat, the sublingual gland enlarges at its end, and 

 loses its flattened form ; the enlarged end is closely attached to the sub- 

 maxillary gland, and is enclosed in the firm capsule of this gland, so that 

 at first sight it appears to form part of it. 



The ducts from the lobules of the submaxillary gland unite, either 

 in the connective tissue which stretches from the hilus of the gland, or 

 in the hilus itself. The gland duct the duct of Wharton runs from 

 the hilus to its opening underneath the tongue, without receiving, except 

 in rare cases, any further accession. 



The sublingual gland in about its anterior two-thirds consists of 

 flattened lobules, the ducts of which enter the main duct on its course 



1 Physiological investigations on the salivary glands have, for the most part, been 

 carried out on the larger glands, namely, the submaxillary, the parotid, and the sublingual. 

 But such conclusions as we may be able to form with regard to these, we may apply with 

 little change to the numerous smaller glands which pour their secretion into the mouth 

 and pharynx, and, indeed, to the lachrymal glands and glands of the nasal mucous mem- 

 brane also. Both in histological and physiological characters the lachrymal gland 

 resembles an albuminous salivary gland. It receives cranial secretory fibres by way of the 

 lachrymal branch of the fifth nerve ; the origin of these fibres from the medulla has not 

 been investigated. It receives sympathetic fibres by way of the cervical sympathetic and 

 the blood vessels of the gland. Secretion can be produced reflexly by stimulating most, 

 if not all, sensory nerves. 



The animals on which investigations have been made are chiefly the dog, cat, and rabbit, 

 the horse, ox, and sheep. 



