Killing Bottles
The best killing agents for use in bottles are either potassium cyanide or calcium cyanide. These compounds give a concentration of deadly fumes sufficient to kill most insects in a very short time, which is desirable. Generally, two sizes of bottles are used, and in either of them one of these cyanides may give good results. Only a small supply should be purchased at a time, as they deteriorate rapidly.
Construction.—A pyrex glass test tube or strong ring-necked vial, about three-quarters inch wide and 4 to 6 inches long, makes a good cyanide bottle of the smaller size, [fig. 3]. Put about three-quarters inch of granular potassium cyanide or calcium cyanide flakes in the tube or vial. Cover with a tight plug of cellucotton, on top of which put one or two loose plugs. Instead of cellucotton, you may use sawdust and a plaster of Paris batter. In the latter case, cover the cyanide with one-quarter inch of sawdust and over it pour one-quarter inch of newly mixed, thick batter of plaster of Paris and water. Allow the batter to harden for a few hours; then keep the bottle tightly corked except when it is being used.
Fig. 3.—Cyanide killing bottles. The lethal chemical, 1, is potassium cyanide or calcium cyanide and is covered with a layer of cellucotton, 2, or sawdust, 3, and plaster of Paris, 4. The rest of the bottle is filled with soft, loosely crumpled, lint-free paper, which should be changed whenever it gets damp. The bottles should be tightly corked and labeled POISON. The collector should not test their strength by smelling.
The larger cyanide bottle, [fig. 3], which should be sturdy, may range in capacity from one-half pint to a quart. In the larger bottle, the cyanide should always have the plaster of Paris covering. The layer of sawdust and plaster should be a little thicker than that for the smaller bottle.
Care and Use.—Label all killing bottles and other containers of cyanide conspicuously with the word POISON; keep them tightly corked and away from children or adults who do not realize the extreme deadliness of the compounds. Never test the strength of a killing bottle by taking the cork out and smelling the contents. As an added precaution and safeguard to the collector, tape the bottom of the cyanide bottle to protect it against breakage.
The bottle should be almost entirely filled with loosely crumpled, soft paper, which should be changed whenever it gets damp. This paper will help keep the specimens from rubbing against each other inside the bottle and thereby being damaged.
Each collector should have several cyanide bottles and follow carefully these practices.
1. Transfer insects from net to bottle by holding the uncorked bottle in a fold or corner of the net and crowding one or more of the specimens into it, or “running” the open bottle up the side of the net beneath the specimen or specimens. Most insects can be maneuvered into the bottle easily and the opening temporarily closed by the thumb, or the stopper can be put on. In obstinate cases, it may be desirable to stopper the bottle through the cloth of the net until the specimen is stupefied, after which the insect will drop to the bottom of the bottle.
2. Keep small, delicate insects in a bottle by themselves. Such insects as large beetles are apt to mutilate small flies and other delicate insects in the same bottle.
3. Keep a special bottle for moths and butterflies. When these die they shed large quantities of scales, which stick to and partially spoil other insects.
4. Keep the inside of the bottle dry. Cyanide bottles “sweat”; that is, moisture both from the insects and the plaster condenses on the inside of the bottle. Moisture will mat the hair and appendages of insects and discolor the bodies. Do not crowd the bottle with large insects, especially juicy ones like grasshoppers. Change the paper frequently. Wipe out the bottle with paper or cloth, which should be carefully disposed of in such a way that it cannot poison persons or pets. Keep the killing chemical out of cuts and mouth. Wash hands with care after handling the chemical.
5. Take insects out of the bottles soon after they are dead. Cyanide fumes quickly turn many yellows to red or orange, and also make small specimens brittle so that legs and other parts break off easily.
6. Empty the insects out of the bottles before they have accumulated in a ball at the bottom. To do so will prevent damage to the smaller specimens and discoloration due to “sweating.”
7. Dispose of a cyanide bottle when it will no longer kill insects quickly. Substitute a fresh bottle and you will save time in the field. Be sure to dispose of old bottles in such a way that their deadly contents are out of reach of children and pets.