92 TAXIDERMY. 



them a lustre, by rubbing them strongly with 

 dered pumice-stone, diluted in a very little water ; 

 and, for the finishing, we rub them afresh, but with 

 a softer brush, and tripoli or rotten stone reduced 

 to a very fine powder. 



[> There are some species from which we take away 

 the calcareous matter, even to the mother-of-pearl. 

 This operation frequently wastes the shell so much 

 as to destroy the characters ; this is prejudicial to 

 science, although it is pleasing to the eye, and we 

 ought not to permit it unless we possess several of 

 the same species. This is the most tedious of all 

 operations. To succeed, we must remove this 

 calcareous matter with a file, and when we ap- 

 proach the extremity of the spire it requires great 

 management. As it is very thin in this place, 

 we must at each stroke of the file examine if we 

 have not gone too deep ; without this precaution 

 we should make a hole in the shell, and the labour 

 would be completely lost. If by patience we hap- 

 pen to expose or discover the mother-of-pearl en- 

 tirely, we soften the file with a piece of buffalo skin, 

 on which we put powdered pumice diluted with a 

 little oil ; we then take another piece of skin and 

 tripoli, and afterwards give the last polish with very 

 fine red ochre. However pleasing the results of 

 this operation may be, the value of the shell is 

 much diminished in the eye of a naturalist. 



We can by the above method, clean shells of all 



