8 ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 39 



damp. This paper will help keep the specimens from rubbing 

 against each other inside the bottle and thereby being defaced. 



Fig. 3.— Cyanide collecting bottles. Killing bottles of at least two sizes 

 should be included in every collector's equipment. The lethal chemical, 1, is 

 potassium cyanide, sodium 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 paper, which should be changed 

 whenever it gets damp. The bottles should be tightly corked and labeled 

 POISON. The collecter should not test their strength by smelling. 



