176 NATURE TEACHING 



injuries caused. Thus lists may be made of insects 

 found upon cabbages, turnips, corn, lettuce, peas, beans, 

 roses, celery, etc. ; these lists may prove of considerable 

 interest and value. In preparing these lists, efforts 

 should be made to observe the habits of the insect and 

 to obtain all the stages from the egg to the mature 

 insect 



Collect specimens of the snails and slugs found in 

 the garden. Observe the shell in snails, and note how the 

 animals withdraw into it when touched or alarmed in any 

 way. Compare with slugs in which the shell is appar- 

 ently absent. Put snails and slugs to walk on a piece 

 of glass, and looking at them from beneath observe 

 the wave-like contraction of the muscles. Notice their 

 eyes, their method of feeding. Keep some for a time 

 in a box, and supply them with leaves ; they may lay 

 eggs, and if so watch the development of the young 

 animals. 



Insects required as specimens are best killed by 

 putting them into a "killing-bottle." This is a wide- 

 mouthed stoppered bottle in which some fragments of 

 cyanide of potassium have been placed, and some plaster 

 of Paris, mixed with water to the consistency of thick 

 cream, poured over the cyanide so as to cover it com- 

 pletely. When the plaster has set, the bottle is ready for 

 use, and any insect placed in it is quickly killed. Owing 

 to the extremely poisonous nature of potassium cyanide, 

 it is desirable that these killing-bottles should be 

 purchased ready for use. When the bottles are old and 

 exhausted, care should be taken in disposing of them, so 

 as to avoid injury to persons or animals by any remain- 



