94 NATURE TEACHING. 



exposed to light for several hours (roses, ama- 

 ranthus). Plunge them into boiling water for 

 about two minutes and then place in alcohol 

 (high wines, rum or other available spirit). 

 When the liquid has become of a deep green 

 colour owing to the leaf-green being extract- 

 ed pour it off and add fresh alcohol, re- 

 peating this until the leaves are free from 

 colour. Put one or two of these leaves in 

 water containing a small quantity of iodine 

 solution ; they will turn blue. The colour 

 will not be a pure bright blue, owing to the 

 brown stain communicated to the tissues by 

 the iodine, the resulting colour is therefore of 

 a somewhat greenish hue. 



3. Take a plant, with smooth leaves, grow- 

 ing in a pot, and leave it exposed to the 

 sunlight from morning to afternoon. Then cut 

 off one-half only of two or three leaves, leaving 

 the other halves attached to the plant. Test 

 the cut-off halves for starch, and, if they have 

 plenty, place tho whole plant in the dark for 

 several hours, either in a cupboard or covered 

 up by a kerosene tin, taking care that no light 

 at all gets to it. Now cut off the remaining 

 halves of the leaves tested previously and test 

 these in exactly the same way. If they have 

 been in the dark long enough (some plants 



