424 THE NERVOUS REGULATION OF THE BLOOD-VESSELS 



ton's duct, it turns abruptly and attains the aforesaid glands by way of 

 this duct. Under ordinary conditions of experimentation, these two 

 sets of fibers possess an antagonistic action upon the vascularity of 

 these glands, because the cerebral nerve or chorda tympani possesses 

 vasodilator and the sympathetic nerve vasoconstrictor qualities. The 

 former change is associated with a secretion of a large quantity of 

 very watery saliva, and the latter with a scanty production of a very 

 viscous and turbid saliva.^ 



These changes may be studied most advantageously in a dog or 

 large cat. The stimulation of the chorda is undertaken as a rule in the 

 triangle where this nerve leaves the lingual to attach itself to Wharton's 

 duct. The excitation of the sympathetic may be accomplished at 

 any point of its course along the neck, but as the vagal and sympathetic 

 fibers of the dog intermingle, it becomes necessary to apply in this case 

 the electrodes to the distal (cephalic) end of this nerve. .It should be 



Fig. 224. — Schema Illustratikg the Nerve Supply of the Submaxillaey Gland. 

 SG, submaxillary gland; supplied by a small aitery from the carotid system (CA). 

 It is drained by a small vein which generallx enters the facial {FV) at its point of con- 

 fluence with the lingual vein (LV). The external (ESV) and internal (JSV) maxillary 

 veins invest the gland and unite to form the external jugular vein (EJV). The sympa- 

 thetic nerve supply is derived from the sup. cerv. ganglion (SCG). The chorda tympani 

 (CT) attaches itself to the lingual nerve LiV and then to Wharton's duct iW);S, lower 

 jaw. 



remembered, however, that we are concerned at this time solely with 

 the aforesaid vascular reaction and not with any other effect whioh 

 this stimulation might produce. In the cat, it is possible to isolate 

 the sympathetic fibers from the vagus proper, because their line of 

 contact is clearly marked by a small blood-vessel. If the surface of 

 the submaxillary gland is now fully exposed to the view, it will be seen 

 that the stimulation of the chorda causes it to redden, while the excita- 

 tion of the (vago-) sympathetic causes it to pale. These changes 

 in the vascularity of this organ may also be made out manometrically, 

 or, as has been done by Burton-Opitz,^ by means of the stromuhr 

 inserted in the distal end of the external jugular vein. In the latter 

 case, however, all tributaFy veins must first be ligated in such a manner 

 that solely the blood from the submaxillary gland is enabled to enter 



^ Heidenhain in Hermann's Handb. der Physiologie, v, 1883. 

 a Jour, of Physiol, xxx, 1903, 132. 



