EXPERIMENTS AND PRACTICAL WORK 85 



breeding places (pools, empty tins, broken bottles, &c.) 

 to be found at home or near the school. 



Expt. 211. Stagnant Pools of Water should be 

 filled up. Fill up any stagnant pools of water found 

 near your home, and likely to form suitable places in 

 which mosquitoes may lay their eggs. 



Expt. 212. Empty Cans and Half-broken Bottles 

 likely to collect Water should be removed. From 

 time to time collect empty tins and half-broken bottles 

 left lying about, and bury them so as to prevent their 

 becoming breeding places for mosquitoes. 



Expt. 213. Mosquitoes often breed in Places used 

 for storing Water. Constantly examine barrels and 

 other vessels in which water is stored for use. 



Expt. 214. Kerosene Oil kills Wrigglers if poured 

 on to the Water in which they are found. Pour some 

 water containing wrigglers into a glass; observe that the 

 wrigglers come to the surface to breathe. Pour some oil 

 on the surface of the water, and note that the wrigglers 

 soon die, because the oil prevents their getting air. 



Expt. 215. Common Wrigglers found in Water 

 change into Mosquitoes. Put some wrigglers into a 

 bottle not quite filled with water, and covered over 

 with a cloth bag. Notice the wrigglers from day to 

 day, and observe the changes that take place until the 

 adult mosquitoes are produced. 



Expt. 216. How to detect Wrigglers of the Malaria 

 Mosquitoes. Observe that- these rest in a horizontal 

 position when they are breathing at the surface of the 

 water. 



Expt. 217. How to detect the Malarial Mosquitoes. 



Carefully watch mosquitoes as they bite, and observe 

 that in malarial districts some stand with their bodies 



