154 MANUAL OF THE MOLLUSCA. 
lingual teeth; for if put up in strong spirit they become so 
hard that it is almost impossible to make good preparations from 
them, and in weak spirit they will not keep for any length of 
time. 
Alcohol.—The cheapest alcohol for preserving natural history 
objects, at home, is sold as ‘‘ methylated spirit ;” it contains ten 
per cent. of ordinary wood spirit, and being undrinkable, is free 
of duty. When many specimens are put up together the spirit 
becomes much diluted, and should be changed. The soft tissues 
of bivalves, and spiral bodies of the univalves soon decompose 
in weak spirit. But for permanent use, in Museums, proof 
spirit may be diluted with an equal bulk of water. Cotton wool 
may be put with the specimens in spirit, especially with cuttle- 
fish, to preserve them from distortion by pressure. 
Goadby’s solution is prepared by dissolving 4 lb. of bay salt, 
20 grains of arsenious acid, or white oxide of arsenic, and 2 
grains of corrosive sublimate, in 1 quart of boiling rain-water. 
Burnet’s solution (chloride of zinc), largely diluted, is now 
used at the British Museum for the preservation of fishes and 
other objects, in glass jars. It has several advantages over 
spirit ; being undrinkable, and not inflammable, and the con 
centrated solution (sold by all druggists) is much less bulky. 
Muriate of Ammonia is recommended by Mr. Gaskoin, for 
removing any unpleasant odours which may arise from prepara- 
tions when taken out of spirit for examination. (See p. 143.) 
A solution of Chloride of Calcium has been employed by 
General Totten, United States Engineers, for preserving the 
flexibility of the epidermis in various shells. The solution of 
this deliquescent salt (which any one can make by saturating 
hydrochloric acid with marble) keeps the object which has been 
steeped in it permanently moist, without injuring its colour or 
texture; while its antiseptic properties will aid in the preserva- 
tion of matters liable to decay. (Professor J. W. Bailey, in 
Silliman’s Journal, July, 1854.) 
