286 



INSECT LIFE. 



and the one that is commonly employed, is by the 

 use of a cyanide bottle. Each pupil, except very 

 young ones, should have such a bottle. The bottles 

 can be prepared, either by the teacher or by a drug- 

 gist, in the following manner :- 



Take a wide-mouthed bottle holding four or six 

 ounces. Put in this bottle a piece of cyanide of potas- 

 sium, about three fourths of an inch square, and 

 water enough to cover the cyanide ; and then im- 

 mediately, before there is time for the cyanide to 

 dissolve, put enough plaster of Paris in the bottle to 

 entirely soak up the water. In this way the cyanide 



will be firmly cemented in place in the 

 bottom of the bottle. The bottle 

 should then be left open in a shady 

 place for an hour to dry, and then se- 

 curely corked with a long cork and 

 labeled Poison, after which it is ready 

 for use (Fig. 254). 



In using a cyanide bottle care should 

 be taken not to leave it open unneces- 

 sarily, lest it lose its strength. With 

 proper care a bottle will retain its 

 strength for several months. 

 Specimens placed in the bottle to be killed should 

 be left there for at least a half hour. They may be left 

 in the bottle several hours, even over night, without 

 injury. Thus a collecting trip may be made one day 

 and the specimens left in the bottle till the following 

 day before they are pinned. If it is necessary to re- 

 turn an insect to the cyanide bottle on account of its 

 revival after it is pinned, the pin should be removed, 

 for the gas in the bottle will corrode it. 



FIG. 254. 



