T.XXiV. 5.6.7.8. OF THE SALIVA AND TEARS. 317 



5. This nafal duct is likewife excited into ftrong 

 aelion by fenfitive ideas, as in grief, or joy, and then 

 ulfo by its afibciations with the lacrymal gland it 

 produces a great flow of tears without any external 

 ilimulus ; as is more fully explained in Seel:. XVI. 8. 

 on Inftindt. 



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

 companion, who are faid to have acquired a volun- 

 tary power of producing a flow of tears in the eye; 

 which, from what has been faid in the fection on 

 Inftincl: above mentioned, I fhould fufpect, is per- 

 formed by acquiring a voluntary power over the 

 aclion of this nafal duel. 



7. There is another circumftance well worthy our 

 attention, that when by any accident this nafal duel: 

 is obftructed, the lacrymal fack, which is the belly 

 or receptacle of this gland, by flight preflure of the 

 finger is enabled to difgorge its contents again into 

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

 the biliary duels are obtfru&ed, is returned into the 

 blood by the veffels which fecrete it ? 



8. A very important though minute occurrence 

 muft here be obferved, that though the lacrymal 

 gland is only excited into aclion, when we weep at 

 a diftrefsful tale, by its aiTociation with this nafal 

 duel, as is more fully explained in Seel. XVI. 8 ; 

 yet the quantity of tears fecreted at once is more 

 than the puncta lacrymalia can readily abforb ; which 

 {hews that the motions occasioned by ajjociatiom are fre- 

 quently more energetic than the original motions, by which 

 they were occasioned. Which we (hall have occafion 

 to mention hereafter, to illuftrate, why pains fre- 

 quently exift in a part diflant from trre caufe of 

 them, as in the other end of the urethra, when a ftone 

 Simulates the neck of the bladder. And why in- 

 flammations frequently arile in parts diftant from their 

 caufe, as the gutta rolea of drinking people, from an 

 inflamed liver. 



Ys The 



