PRESERVING WATER ANIMALS 



suggest. If chloroformed they should be enclosed in a tight 

 pail with a little chloroform sprinkled on a cloth. 



Occasionally it may be desirable to use chloretone, though 

 not often. This is an anaesthetic which will kill small water 

 animals painlessly and leaves them relaxed and ready to be 

 put into alcohol or formalin. It is sold in crystals which 

 can be dissolved in water to make a saturated solution. 

 Such a stock solution should be kept on hand and a little of 

 it used as needed. The animal should be placed in a little 

 water and drops of chloretone added until it is entirely 

 inert. 





Fig, 36. — Specimen vials and rack for holding them. 



Preserving insects and other anitnals. — Alcohol (ethyl 95%) 

 diluted with about one-fourth water is the best general pre- 

 servative for sponges, worms, leeches, crustaceans, water- 

 mites, soft-bodied insects, frogs and salamanders and tad- 

 poles, and for mollusks if the soft parts are to be kept. But 

 alcohol is expensive and difficult to secure; and though 

 nothing else is so satisfactory for insects, formalin is much 

 cheaper and often better for other things,- especially larger 

 animals like crayfishes, frogs, and turtles. In these a slit 

 should be made in the abdominal wall to let the preservative 

 in upon the viscera. Eggs and larvae of frogs and other 

 amphibians keep well in a weak formalin solution. Formalin 

 is sold at almost any drugstore and is not expensive; the 

 proper solution may be made by adding one ounce of com- 

 mercial (40%) formalin to sixteen ounces of water. 



Storing specimens in alcohol (Fig. 36). — Small specimens 

 are best kept in well-corked vials. There are several types 



41 



