SALIVATION PTYALISM. 459 



to this, Lehmann found that at the commencement of mercurial pty 

 alism the excretion was not saliva but mucus, mingled with shreds of 

 epithelium from the oral mucous membrane. The preparations of iodine, 

 which induce stomatitis less frequently, cause salivation far more rarely, 

 although we can detect their presence in the saliva quite early. We 

 do not know whether the salivation produced by muriate of gold 

 and other metallic and vegetable substances originates in the same 

 way. 



2. In many cases, salivation appears to depend on irritation, affect- 

 ing the gastric or intestinal mucous membrane, perhaps also the uterus 

 or other organs. Frerichs has shown, by experiment, that irritation of 

 the gastric mucous membrane increases the secretion of saliva ; for, 

 when he introduced food into the stomachs of dogs through fistulous 

 openings, there was profuse salivation ; if he used common salt, quan- 

 tities of saliva flowed from the mouth. These experiments appear 

 to prove that irritation of the gastric nerves is also reflected to the 

 nerves governing salivation, and they at least partly explain the 

 increased flow of saliva accompanying many pathological states of the 

 stomach, such as ulcer or cancer of the stomach, and preceding vomit- 

 ing, whether induced by emetics, overloading, or disease of the stom- 

 ach. It seems probable, also, that the same cause induces the saliva- 

 tion 'so constantly accompanying the pains produced by worms in the 

 intestines, that the laity who are aware of this symptom have the 

 most wonderful hypotheses about the flow of water into the mouth 

 from the irritation of worms. We have less reason for referring the 

 salivation which not unfrequently occurs during the first months of 

 pregnancy, or in hysteria, to an excitement of the genital nerves re- 

 flected to the secretory nerves of the sah* vary glands. 



3. Salivation depends on certain mental influences. We see how 

 the secretion is increased in disgust or desire. As a proof that abnor- 

 mal excitement of the brain may directly increase the secretion of sa- 

 liva, we may note the fact that physiologists have been obliged to 

 locate the origin of the nerves, governing the secretion of saliva, in the 

 brain. The activity of the salivary glands is increased in the same 

 way by irritation of the trigeminus and facial nerves, even at points 

 where no sympathetic filaments are mingled with them, that is, above 

 the ganglia. 



4. Occasionally salivation occurs in the course of diseases, such as 

 typhus, intermittent, etc., without other perceptible cause ; its occur- 

 rence in these diseases has even been regarded as critical. 



Finally, some apparently heaJfchy persons suffer from obstinate sali- 

 vation without perceptible cause. In insane and old people, the flow 

 of saliva from the mouth does not appear to depend on its increased 



