Sect. XXIV. 2. 3. AND TEARS. 215 



and concealed glands may be better underftood from their anal- 

 ogy to this. 



3. This fimple gland confifts of two abforbing mouths, a bel- 

 ly, and an excretory duct. As the tears are brought to the in- 

 ternal angle of the eye, thefe two mouths drink them up, being 

 ftimulated into action by this fluid, which they abforb. The 

 belly of the gland, or lacrymal lack, is thus filled, in which the 

 faline part of the tears is abforbed, and when the other end of 

 the gland, or nafal duel, is ftimulated by the drynefs, or pained 

 by the coldnefs of the air, or affected by any acrimoneous duft 

 cr vapour in the noftrils, it is excited into action together with 

 the fack, and the tears are difgorged upon the membrane, which 

 lines the noftrils ; where they ferve a lecond purpofe to moiften, 

 clean, and lubricate^ the organ of fmell. 



4. This gland, when its nafal duct is ftimulated by any very 

 acrid material, as the powder of tobacco, or volatile fpirits, not on- 

 ly difgorges the contents of its belly cr receptacle (the lacrymal 

 fack), and abforbs haftily all the fluid, that is ready for it in the 

 corner of the eye 5 but by the aflociation of its motions with 

 thofe of the lacrymal gland, excites that alfo into increafed ac- 

 tion, and a large flow of tears is poured into the eye. 



5. This nafal duct is likewife excited into ftrong action by 

 fenfitive ideas, as in grief, or joy, and then alfo by its aflbciations 

 with the lacrymal gland it produces a great flow of tears with- 

 out any external ftimulus 5 as is more fully explained in Sect. 

 XVI. 8. on Inftinct. 



6. There are fome, famous in the arts of exciting companion, 

 who are faid to have acquired a voluntary power of producing a> 

 flow of tears in the eye ; which, from what has been faid in the 

 fection on Inftinct above mentioned, I {hould fufpect, is perform- 

 ed by acquiring a voluntary power over the action of this nafal 

 duct. 



7. There is another circumftance well worthy our attention, 

 that when by any accident this nafal duct is obftructed, the lac- 

 rymal fack, which is the belly or receptacle of this gland, by 

 flight prefFure of the finger is enabled to difgorge its contents 

 again into the eye \ perhaps the bile in the fame manner, when 

 the biliary ducts are obftructed, is returned into the blood by 

 the veflels which fecrete it ? 



8. A very important though minute occurrence muft here be 

 obferved, that though the lacrymal gland is only excited into ac- 

 tion, when we weep at a diftrefsful tale, by its aflbciation with 

 this nafal duct, as is more fuiljr explained in Sect. XVI. 8 ; yet the 

 quantity of tears fecreted at once is more than the puncta lacry- 

 rnalia can readily abforb ; which {hews that the motions accafwned 



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