...Spirit should not be used too strong, as its effect is to contract the outer surface, and thus closing the pores prevent the alcohol from penetrating through...often used, so long as the traveller has a reserve sufficient to bring it back to its requisite strength. In selecting specimens for immersion, regard...

...used too strong, as its effect is to contract the outer surface, and close the pores, thus preventing the alcohol from penetrating through to the inner...alcohol when first put in. It will be found that after a few days the spirit retains its strength : when this is the case, the specimen will be perfectly...