BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [8] 



To preserve small, delicate animals, such as eggs and larva?., it is 

 well to place the small tube containing the objects in alcohol, closed 

 with a cotton plug, inside a larger vessel, which is likewise filled Avith 

 alcohol. This arrangement prevents danger from evaporation and 

 minimizes the liability to breakage. One must see, however, that the 

 cotton contains no acids and does not stain the alcohol. Absorbent 

 cotton is the most suitable, of course, but the best quality of ordinary 

 cotton will answer every purpose. 



For large, flat objects, such as Asterids, Pleuronectids, and the like, 

 rectangular jars with flat sides are recommended. These jars are made 

 to be closed with a plate of glass, cemented on. Grutta-percha cement 

 is generally used. Such receptacles have the great advantage that 

 they do not distort the view of the object within them. For delicate 

 forms, which are long and stiff, like Fmiiculina, glass tubing of proi)er 

 size, cut ofl' at the right length, is used, one end being closed in the 

 Bunsen flame and the other with a cork. 



For preliminary manipulations much use is made of glass crystallizing 

 dishes with flat bases and perpendicular sides, in which many specimens 

 can be placed in little liquid without touching or interfering with one 

 another. They are especially advantageous for keeping animals alive 

 in sea water, letting them remain at rest until thoroughly distended; 

 for killing by different methods, either slowly or quickly, and for 

 hardening objects in different solutions until they are transferred to 

 permanent receptacles. These crystallizing dishes have ground edges 

 so that they maybe tightly covered with disks of glass, when desirable. 

 For hardening worms and other elongated animals use may be made of 

 long rectangular vessels covered with a sheet of glass, or of the zinc 

 trays to be described later. 



It is also necessary to have a number of ordinary beakers (or battery 

 jars) of different sizes, which serve for the preserving of animals alive, 

 tubes for the reception of small animals, pipettes for the extraction of 

 minute forms from jars of water, glass rods, reagent bottles, graduated 

 cylinders, etc. 



For preserving animals, especially fish, of a size too great for such 

 glass receptacles as have been mentioned, a rectangular case or box of 

 zinc with a shallow trough around the margin is very useful. The 

 cover, likewise of zinc, has its edge made to fit into the trough. To 

 prevent evaporation the trough may be filled with water and a layer of 

 oil. The cover has an opening in the middle to permit the escape of 

 the air which is compressed under it by closing the box. This opening 

 is provided with a cork. It must be acknowledged that these boxes 

 have the disadvantage that, after a time, the zinc becomes corroded, 

 probably by some acid formed in tho alcohol through the action of 

 dead animal matter. It is a good plan to protect the metal box by an 

 exterior wooden case. 



In place of the rectangular vessels of glass for hardening animals of 

 elongated form, the station uses some made of zinc with a layer of wax 



