i66 LETTER VIL 



1 8. "To dlfpatch this pretended difficulty, 

 without wandering from the fubject of our 

 prefent Controverfy, I fliall only put you in 

 mind of thofe Shells, that are fometimes found 

 in the Kidneys, Impofthumes, and Stomach, of 

 which we have fuch cxaft and late accounts, 

 that the matter of fad: is undoubtedly certain; 

 (fee the Nouvelles de la Republique^ for Decern^ 

 6er i686y fee alfo Ambrofe Parens^ and other 

 Anatomical Writers :) For if I ihould afk you, 

 for what Creatures thefe things are generated, 

 you muft be forced to have recourfe to a di- 

 ftindtion of your Aphorifm, which may be 

 eafily accommodated to my Hypothefis. 



19. " If you think to elude the force of thefe 

 Inftances, by faying, That the Shell in an Im- 

 pofthume, is a fort of Monfter, from which 

 we muft not draw a general conclufion j I an- 

 fwer, that I will not diipute about words, nor 

 make too general Conclufions. If Shells in the 

 Kidneys, or in Impofthumes, be called Mon- 

 fters in yourDidtionary, you may, if you pleafe, 

 beftow the fame Title on thofe of Certaldo. 

 Neither muft you ftart new Difficulties, by 

 comparing the multitude of thefe, with the 

 fmall Number of the others : for if the Kidney 

 were as big as a Mountain, and contained as 

 great a quantity of Matter, fit for the Forma- 

 tion of Shells, as the Hill oiCertaldo^ wefhould 



** doubtlefs. 



