9C 



ture supersedes the first, in those cases where carbonate 

 of lime enters largely into the composition, and where it 

 is an object to preserve transparency ; but, where opacity 

 is required, to render matter conspicuous, as in dissections, 

 exhibiting the nervous system of the smaller animals, &c, 

 the former mixture is better. 



Although foreign to the subject of my paper, I have 

 ventured to call your attention to this subject, conceiving 

 it of very great importance to naturalists and physiologists. 



