CHAP. I.] PAROTID SALIVA. 23 



and rabbit stimulation of the sympathetic causes secretion, very 

 much as in the case of the submaxillary gland l . 



Mode of ob- I n man the parotid saliva may be collected by 

 taining pure inserting a tube through the mouth into the duct of 

 parotid Steno 2 . In the lower animals by exposing the duct 



and tying a silver cannula into the duct. 



Insertion of " As it is hardly possible to insert a cannula into one's 



a cannula into own parotid duct, a second person must be employed, who 

 the human pa- should sit opposite a good light. .... The method is 

 rotid duct. as follows : Draw one angle of the mouth outwards and 



forwards so as to stretch the cheek. Opposite the second molar tooth of 

 the upper jaw the small papilla is seen which marks the orifice of Stenson's 

 duct. Insert the cannula and hold it steadily but carefully in its place, 

 then a third person may blow into the mouth some vapour of ether, or 

 introduce a little diluted tincture of pyrethrum 3 ." 



Insertion of I* 1 a deeply anaesthetized animal, the hair is clipped 



a cannula into " from the cheek between the orbit and the angle of the 

 the parotid mouth. On running the finger along the lower border of 

 duct of the the zygomatic arch from behind forwards, its anterior and 

 inferior root is felt at its insertion into the superior maxilla, 

 forming an arch of which the convexity is directed backwards. At the end 

 of this arch, between its insertion into the maxillary bone and the alveolus 

 of the second molar tooth, a little depression is felt. Exactly on a level 

 with this depression, and in a line with the insertion of the zygomatic 

 arch, make an incision through the skin, cutting obliquely in a direction 

 from the inner canthus of the eye towards the angle of the mouth. 



" On dividing the subcutaneous cellular tissue, the facial vein and 

 artery, a nerve and the parotid duct will be found all together. The duct 

 lies more deeply and runs from behind forwards, while the artery with its 

 accompanying vein pass from above downward. 



"It is of a pearly white colour. Isolate it and divide it as near the 

 mouth as possible. The wound must be closed round the duct, and the 

 duct secured in it by a suture, just as in the case of the submaxillary gland 4 ." 



Physical and Chemical Characters of Normal Parotid Saliva. 

 Physical Parotid saliva of man is a clear, transparent, non- 



characters of viscid liquid, possessed of an alkaline reaction 5 , except 

 parotid a t the very commencement of its flow, when its reac- 



tion may be faintly acid. Its specific gravity varies 



1 Langley found (Journal of Physiology, Vol. x. 1889, p. 320) that for a time after 

 the parotid of the dog has been secreting, either reflexly or by stimulation of Jacobson's 

 nerve, stimulation of the sympathetic always produced a secretion. Similarly wheii 

 a secretion is going on after injecting pilocarpin, stimulation of sympathetic in- 

 creases at first the rate of secretion and then slows it. So the sympathetic in the dog 

 as in other animals contains secretory fibres, the ordinary decrease of secretion on 

 stimulating the sympathetic being possibly due to the sympathetic vaso-constrictor 

 fibres acting more promptly and completely in the dog's parotid than elsewhere. 



2 Eckhard, Beitr. z. Anat. u. PhysioL, Vol. n. p. 205. 



3 Brunton, Handbook of the Physiological Laboratory, p. 467. 4 Ibid. p. 468. 

 5 See abstract of papers on the reaction of saliva by Astaschewsky and Fubini in 



Maly's Jahresbericht, Vol. vm. (1878), pp. 234 and 235. 



