134 PRODUCTION OF IDEAS. SECT. XIV. 8. 



a pin is preffed upon our fkin, produces pain, (and 

 when this pain of the fenfe of diftention is "ilighter, 

 it is termed itching, or tickling), without any idea 

 of folidity or of figure ; an excefs of heat produ- 

 ces fmarting, of cold another kind of pain ; it is 

 probable by this fenfe of heat the pain produced by 

 cauftic bodies is perceived, and of electricity, as 

 all thefe are fluids, that permeate, diflend, or de- 

 compofe the parts that feel them. 



SECT, 



