THE CONQUEST OF THE MOSQUITOES 185 



a leaf or even damp mud will serve for the egg 

 until it hatches a few hours or a few days later, 

 and in Panama, where it rains many days of the 

 year, there may be water standing anywhere out 

 of doors that will do for egg hatcheries. 



Mosquitoes do not travel far. If they are 

 killed and the eggs kept from hatching close to 

 towns and encampments, they do not trouble 

 very much. Around the Canal Zone towns the 

 brush was cut down, not only on account of the 

 moisture in the leaves, but because it often hid 

 old pots and cans that held water. Where water 

 and wrigglers could not be emptied or drained 

 away it was sprayed with oil. When the little 

 mosquito wrigglers came to the surface for air, 

 they got the oil in their breathing tubes and choked 

 to death. 



The uneven streets of the towns were given new 

 smooth pavement that would not hold puddles of 

 water (Fig. 80) . The drains and sewers were kept 

 running freely and treated with mosquito poison 

 every few days. 



The buildings were just as carefully inspected. 

 Since the French had not known that mosquitoes 

 were dangerous, they had not been afraid of them. 

 Their big hospital in Ancon had to be cleaned 

 and screened and all the grounds around it 

 cleared to the sunlight. . 



The French nuns who had nursed in the hospital 

 had been very proud of the beautiful tropical 



13a 



