178 OF INSTINCT. SEcr.XVl.8. 



duel, that opens into the noftrils : the aperture of 

 this duel is formed of exquifite fenfibility, and 

 tvhen it is ftimulated by odorous particles, or by the 

 drynefs or coldnefs of the air, the fack contracts it- 

 felf, and pours more of its contained moiflure on 

 the organ of fmell. By this contrivance the organ 

 is rendered more fit for perceiving fuch odours, 

 and is'preferved from being injured by thofe that 

 are more ftrong or corroiive. Many other recep- 

 tacles of peculiar fluids difgorge their contents, when 

 the ends of their duels are Simulated; as the gall 

 bladder, when the contents of the duodenum ftirnu- 

 late the extremity of the common bile duel : and 

 the falivary glands, when the termination of their 

 duels in the mouth are excited by the (limulus of 

 the food we mafticate. Atque veficulae feminales 

 fuum exprimunt fluidum glande penis fricata. 



The coldnefs and drynefs of the atmofphere, com- 

 pared with the warmth and moifture, which the new- 

 born infant had juft before experienced, difagreeably 

 affecls the aperture of this lacrymal fack : the tears, 

 that are contained in this fack, are poured into the 

 noftrils, and a further fupply is fecreted by the lacry- 

 mal glands, and diffufed upon the eye-balls ; as is very 

 vifible in the eyes and noftrils of children foon after 

 tbeir nativity. The fame happens to us at our maturer 

 age, for in levere frofty weather, fnivelling and tears 

 are produced by the coldnels and drynefs of the air. 



But the lacrymal glands, which ieparate the tears 

 from the blood, are fituated on the upper external 

 part of the globes of each eye ; and, when a 

 greater quantity of tears are wanted, we contracl 

 the forehead, and bring down the eye-brows, and 

 ufe many other diilortions of the face, to comprefs 

 thele glands. 



Now as the 1 fuffocating fenfation, that produces 

 refpiration, is removed ahnoft as foon as perceived, 

 does not recur again : this difagreeable irrita- 

 tion 



