MALARIOUS 'COlWrDES* - '* > '> > 161 



life of the female has been estimated at from two to 

 many weeks. This time varies with the duration of 

 the egg-laying period, and also with the facilities for 

 the same. There seems great probability that a 

 mosquito, once infected, remains infective for life, 

 but actual experimental demonstration of this 

 opinion has not been made. 



Malaria is widely distributed. No continent is 

 free from it, and the more detailed records of the 

 present day tend to show that it is far more widely 

 spread than was suspected. Further, it is not 

 spread by one species of mosquito alone, but many 

 Anophelines are incriminated, and several kinds 

 have been caught in the same district and found 

 to contain the characteristic sporozoites in their 

 salivary glands. Europe, Italy, Greece, Spain, and 

 Portugal, all have malarious districts. Throughout 

 Africa the Anophelines are distributed, and native 

 children, mostly between the ages of five and ten, 

 act as living reservoirs of the parasite. Many parts 

 of India, even in the more temperate areas, are unfit 

 for European occupation permanently, and the 

 barracks of European and native troops alike in 

 certain parts, particularly in the northern district, 

 have acquired a sinister reputation. Southern Asia 

 generally is malaria-ridden to some extent, particu- 

 larly in low-lying districts, where water is unable 

 to drain away. The interruption of the world's 

 commerce by the repeated failures of the attempts to 

 cut the Panama Canal, and the lack of development 

 of the abundant vegetable and mineral resources of 

 the Amazon and Orinoco valleys, are largely due to 



