154 MANUAL OF THE MOLLTTSCA 



lingual teeth ; for if put up in strong spirit they become so 

 hard that it is almost impossible to make good preparations frotn 

 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 ^ 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. 



Burnefs 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, ia 

 SiUiman's Journal^ July, 1854.) 



