80 A STUDY OF THE INFLUENCE 



anaesthesia, and was administered through a tracheal tube in 

 part of the experiments, the danger of respiratory difficulties 

 resulting from salivary flow induced in the glands as a result 

 of the ether stimulation being thus avoided. In the later 

 stages of the experiments the alcohol introduced usually suf- 

 ficed to maintain the animal in perfect quiet. Fredericq * has 

 recommended the use of alcohol for producing narcosis in 

 rabbits ; it has been found quite satisfactory for this purpose 

 in the dog, the effects passing off with relative rapidity. 



A glass cannula, bent at the end, was tied in Wharton's 

 duct (and occasionally a second cannula into the duct of the 

 sublingual gland). The chordo-lingual nerve was ligatured 

 and cut at some distance centrally to the point where the 

 chorda tympani branches off to the glands. All secretion in 

 the corresponding gland was thus stopped except during 

 stimulation of the chorda, which was accomplished through 

 raising the peripheral end of the cut nerve by the ligature and 

 slipping hook electrodes under it. The interrupted current of 

 a Du Bois induction-coil with a single element was used as the 

 stimulus. Saliva was collected in small graduated cylinders. 

 Alcohol was introduced into the stomach by making an incision 

 through the linea alba, etc., and injecting the fluid directly 

 into the organ thus exposed by means of a large needle- 

 pointed syringe. By careful avoidance of the larger gastric 

 vessels, bleeding was minimal. The general course of the 

 experiments was as follows : A distance between the primary 

 and secondary coil of the inductorium was selected such as a 

 preliminary trial showed to give a medium rate of flow. This 

 stimulus was, so far as possible, kept constant throughout the 

 experiment. The chorda was repeatedly stimulated for periods 

 of one minute, followed by pauses of two minutes, during 

 which the nerve was kept covered. In this way sufficient 

 quantities of saliva for analysis were collected. Before 

 collecting a sample of saliva under any given conditions, the 

 six or seven drops first discharged were thrown away, and 

 thus the fluid stored up from previous stimulation in the 



* Fredericq : Manipulations de physiologic, p. 19. 



