BY DR. LAUDER BRUNTON. 473 



tion of the latter manifests itself in the same way as if the ex- 

 citation were simultaneous. Here, as before, the effect must be 

 verified by comparative experiments. 



98. Simultaneous Section of the Chorda Tympani 

 and Vascular Nerves. Paralytic Secretion. After divi- 

 sion of both nerves, the secretion of the submaxillary gland, 

 which in the normal state only goes on when the gland is 

 directly or reflexly excited, becomes constant and abundant. 

 This effect does not occur until some time after section, and 

 may last for days or weeks. A similar condition of the gland 

 is produced by the introduction of curare into the blood, which 

 is supplied to the gland by its arteries. To show this, proceed 

 as follows : Find the facial artery and prepare it. Then insert 

 and secure a canula, to which an end of India-rubber tubing 

 has been previously fitted in the usual way. Fill the canula 

 with saline solution, and connect it with the nozzle of a Pravaz's 

 syringe previously charged with one per cent, solution of curare, 

 taking care that the India-rubber tube is firmly tied round the 

 nozzle. Open the clip, inject five divisions (about two milligr. 

 of curare), and then close the clip. The same mode of injection 

 may be used for the introduction of solution of atropin, if it is 

 desired to repeat the experiments of Heidenhain previously 

 referred to. 



99. Function of the Submaxillary Ganglion. 

 Bernard found that excitation of the central end of the lingual, 

 when divided near the mouth, produces effects similar to those 

 of excitation of the chorda, i. e., causes the submaxillary gland 

 to secrete even when the trunk of the lingual and chorda has 

 been severed at a point nearer the brain than that at which it 

 is in relation with the ganglion. 



From this, Bernard concluded that the submaxillary ganglion 

 acts as a reflex centre, independently of the central nervous 

 system. More recent observations render it probable that 

 Bernard's result derives its explanation from the anatomical 

 fact that a filament of the chorda exists, at all events in some 

 animals, which accompanies the lingual nerve for about an 

 inch and a half beyond the point at which the chorda separates 

 from it. The effect in question is to be attributed to excitation 

 of this filament, which runs back parallel with the lingual nerve 

 to the submaxillary plexus, and so to the gland. (On this 

 subject, see Schiff, Physiol. de la Digestion, t. I., p. 288, and 

 Haartman's Thesis, 1846. Helsingfors, p. 3T, and PL I. 142.) 



100. Parotid Glands. In most animals the parotid, like 

 the submaxillary gland, does not secrete unless the nerves 

 which regulate its secretion are stimulated, but in the sheep it 

 is said by Eckhard to secrete constantly. Secretion occurs 

 when sapid substances are applied to the posterior part of the 

 tongue, and still more when they are chewed ; but the mere 



