KILLING BOTTLES. 



thin glass. There are many ways of keeping the cyanide 

 in position and the bottle in good condition. The most 

 general way is to pour a thin layer of plaster of paris over 

 a layer (from ^ to x /^ in. deep) of cyanide. However, 

 since such a bottle will quickly get too moist from the 

 specimens and the decomposition of the cyanide, some 

 further device is almost always used. The pieces of 

 cyanide may be wrapped in soft absorbent paper or 

 imbedded in dry sawdust before the plaster is poured on. 

 Another way is to imbed it in dry plaster before pouring 

 on the wet. A piece of blotting paper should be fitted 

 tightly over the plaster after it has "set. " See Plate III. 

 Some do not use plaster but imbed the cyanide in cotton 

 and cover this with a piece of blotting paper or a thin 

 porous cork. A dangerous, but otherwise fairly satis- 

 factory, method is to imbed a piece of cyanide on the inside 

 surface of the cork and have none in the bottle itself. 

 This bottle will be dry but not strong, and as the cork 

 will, in time, become saturated with poison it will be very 

 dangerous. It is always well to have a few narrow strips 

 of loose absorbent paper in the bottle. They prevent 

 injury to the insects by shaking and help keep the bottle 

 dry, as they can be frequently changed. As ordinarily 

 made, a bottle should be allowed to ripen for several days 

 before using. If wanted at once, put a few drops of 

 vinegar or a pinch of boracic acid powder with the cyanide. 

 Collectors of delicate moths and butterflies frequently 

 put a few drops of ether or chloroform in their cyanide 

 bottles before starting out. This is to quiet the insects at 

 once for the cyanide sometimes kills slowly. Experience 

 will teach the collector that some insects die very slowly 

 and revive after apparent death. On the other hand, 

 ether and chloroform make insects brittle and too long an 

 exposure to cyanide fumes changes the color of some 

 insects. 



Practically all beetles and dragon flies, together with 

 dull-colored, hairless insects of other orders, can be killed 

 in alcohol and kept there indefinitely. Fifty % is strong 

 enough for killing and 70% for preserving. Higher 

 grades make them brittle. No fly, bee, butterfly, moth, 

 or any green insect, other than those previously mentioned, 



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