BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [94] 



The wMte deposit of arsenic which, will appear on drying can be washed 

 oif with alcohol. 



AlcoJwl and Corrosive Sublimate. — The same author recommends 

 another preparation consisting of alcohol with a variable quantity of 

 corrosive sublimate added, the strength of the solution varying from 

 100 parts of alcohol to 1 part of corrosive sublimate for the strongest^ 

 to one-tenth of 1 part of sublimate in 100 parts of alcohol for the weak- 

 est. The insects are allowed to remain in this mixture not longer than 

 two hours before drying. The last-described preparation is said to 

 preserve the specimens from mold. Both of these solutions are very 

 poisonous and should be used with care. 



Tivo Liquids to ])reserve Form and Color. — Professor Packard also 

 quotes the formula of A. E. Yerrill for preserving insects in their natural 

 color and form. Two formulas are given ; the first consists of 2^ pounds 

 of common salt and 4 ounces of niter dissolved in a gallon of water and 

 filtered. The specimens should be prepared for j)ermanent preservation 

 in this solution by being previously immersed in a solution consisting 

 of a quart of the first solution and 2 ounces of arsenite of potash in 

 a gallon of water. Professor Packard gives also the formula of M. H. 

 Trois for preserving caterpillars, for which it is claimed that the colors 

 of the caterpillars are preserved perfectly, even when exposed to strong 

 light. The formula for this solution is as follows : 



Common salt grams.. 2.35 



Alum do . . . 55 



Corrosive sublimate centigrams . . 18 



Boiling water liters.. 5 



Allow the liquid to cool and add 50 grains of carbolic acid, and filter 

 after standing five or six days. 



Glycerin. — Glycerin, either pure or mixed with water or alcohol, is 

 frequently used to preserve the larvse of delicate insects. It i3reserves 

 the color and form better than alcohol, but particularly in the case of 

 larvse, it causes a softening of the tissues which renders them unfit for 

 study. 



The Wickersheim Preserving Fluid. — This valuable preserving fluid 

 has been known for some time, but is not very commonly used, on 

 account of frequent disappointment due to the difficulty attending 

 its preparation. It is claimed for it that animal or vegetable bodies 

 impregnated with it will retain their form, color, and flexibility in the 

 most perfect manner. The objects to be jjreserved are put in the fluid 

 for from six to twelve days, according to their size, and then taken out 

 and dried in the air. The ligaments remain soft and movable, and the 

 animals or jolants remain fit for anatomical dissection and study for 

 long periods, even years. It is said to be especially valuable for the 

 preservation of larvse and soft-bodied insects. In order to perfectly 

 preserve the colors, it is necessary to leave the specimens in the fluid, 

 or, if they are taken out, they should be sealed uj) in air-tight vials or 

 vessels. The formula for the flaid is as follows : 



