OF THE SALIVA AND TEARS. SECT. XXIV. 5. & 



falival glands, and on the membranes, which line 

 the mouth, are likewife ftimulated into ftronger 

 action, and abforb the mofe liquid parts of the faliva 

 with greater avidity ; and the remainder is left both 

 in greater quantity and more vifcid. 



The increafed abforption in the mouth by fome 

 flimulatin^ fubflar ces, which are called aftringents, 

 as crab jiiice, is evident from the inftant drynefs 

 produced in the mouth by a fmaii quantity of 

 them, 



As the extremities of the glands are of exquifite 

 tenuity, as appears by their difficulty of injection, it 

 was neceffary for them to fecfete their fluids in a very 

 dilute Rate ; and probably for the purpofe of fiimu- 

 lating them into action, a quantity of neutral fait is 

 likevvife fecreted or formed by the gland. This 

 aqueous and ialine part of all fecreted fluids is again 

 reabfcrbed into the habit. More than half of fome 

 fecreted fluids is thus imbibed from the refervoirs, 

 into which they are poured ; as in the urinary blad- 

 der much more than half of what is fecreted by the 

 kidneys becomes reabforbed by the lymphatics, which 

 are thickly difperfed around the neck of theb adder* 

 This feems to be the purpofe of the urinary bladders 

 of tifh, as otherwife fuch a receptacle for the urine 

 could have been of no ufe to an animal immerfed in 

 water. 



5. The idea of fubflances difagreeably acrid will 

 alfo produce a quantity of faliva in the mouth ; as 

 when we fmell very putrid vapours, we are induced 

 to fpit out our faliva, as if fomething dilagreeable 

 was actually upon our palates. 



6, When difagreeable food in the ftomach produ- 

 ces naufea, a flow of faliva is excited in the mouth 

 by aflbciation ; as efforts to vomit are frequently 

 produced by difagreeable drugs in the mouth by the 



7. A 



