SECT. XXIV. 2. 3. AND TEARS. 215 



and concealed glands may be better underftood from their anal- 

 ogy to this. 



3. This (imple 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, thofe two mouths drink them up, being 

 itimulated into ahon by this fluid, which they abiorb. The 

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

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

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

 by the coldnefs of the air, or affecled by any acrimonious dull 

 or vapour in the noftrils, it is excited into alion together with 

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

 lines the noftrils \ where they ferve a fecond purpofe to moiften, 

 clean, and lubricate, the organ of fmell. 



4. This giand, when its nafal, du6l, is ftimulated by any very 

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

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

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

 corner of the eye ; but by the aflbciation 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 duft is like wife excited into ftrong action by 

 fenfitive ideas, as in grief, or joy, and then aifo by its ailbciations 

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

 out any external ftimulus ; as is more fully explained in Sedl, 

 XVI. 8. on Inftind. 



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

 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 Inftindl above mentioned, I ftiould fufpedt, is perfom- 

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

 duct. 



7. There is another circumftance well worthy our attention, 

 that when by any accident this nafal dudl is obftru&ed, the lac- 

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

 flight prdlure of the finger is enabled to difgorge its contents 

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

 the biliary duds are obftrudted, is returned into the blood by 

 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 affociation with 

 this naial duct, as is more fully explained in Sett. XVI. 8 , yet the 

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

 malia can readily abiorb 5 which {hews that the motions occafwned 



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