which is likewise filled with 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 Aster ids, 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. Gutta-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 Funiculina, glass tubing of proper size, cut off 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 may be 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 pre- 

 serving 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 the alcohol 

 through the action of dead animal matter. It is a good plan 

 to protect the metal box by an exterior wooden case. 



- 12 - 



