312 MATHEWS. 



more watery than normal and has a shorter latent period. It 

 resembles chorda saliva. A similar watery and copious sym- 

 pathetic saliva occurs after the injection of nicotine,"^ or pilo- 

 carpine," and during paralytic secretion. ^^ 



This augmented saliva may be explained, assuming that the 

 nerve acts on the gland cell, as follows : If the chorda and sym- 

 pathetic act as the same gland cells (Heidenhain) it may be said 

 that stimulation of the chorda renders the cells more responsive 

 to a sympathetic stimulation immediately following. If, on the 

 other hand, the chorda and sympathetic innervate different gland 

 cells (Langley), we are forced to the assumption that nerve im- 

 pulses traverse glands outside of the nerve tracts. "When 

 either nerve is stimulated," Langley says, ''there is an irradia- 

 tion of impulses of less intensity to the cells in the neighborhood 

 of those directly affected ; that on stimulation of the chorda 

 tympani the cells connected with it are left for a time in a state 

 of weak excitation, so that irridiation of impulses reaching the 

 gland by the sympathetic is much greater than normal, and these 

 irradiating impulses being weak lead to a more fluid secre- 

 tion."'^^ It can hardly be said, I think, that either of these ex- 

 planations is satisfactory. That irritability of the gland cells 

 probably has nothing to do with this augmentation, but that it 

 is the simple result of the presence of an abnormally large 

 amount of fluid saliva in the gland is shown by the injection of 

 innocuous fluid into Wharton's duct. By this means we pass- 

 ively distend the ducts and aveoli, without the intervention of cell 

 activities. Following stimulation of the sympathetic causes an 

 augmented secretion. I have tried such experiments only in the 

 case of the dog's submaxillary, a somewhat unsatisfactory gland, 

 owing to the viscidity of the saliva. The experiment, particu- 

 larly if tried on a fresh gland full of viscous saliva, is not always 

 successful. The cause of the failures has not been investigated, 

 but I suppose they are due to the unavoidable driving into the 

 gland of the viscous saliva and partly to the use of too great 

 pressure in such cases, causing an over-distension of the ducts 

 and a consequent injury to the nerves. The positive results are, 

 however, sufficiently conclusive. 



