CONDITIONS INFLUENCING PREVALENCE 195 



appears simple and obvious :- Construct a single covered 

 tank at the well head, and distribute the water by means 

 of pipes provided with taps. But in practice the expense, 

 and the difficulty of obtaining sufficiently skilled workmen 

 to construct such an installation and keep it in order are 

 prohibitory. What might, however, be done, would be to 

 insist on each tank being carefully cleaned out and left 

 dry for a few hours once in every week ; but it is difficult 

 to persuade even Europeans to do this, and though in 

 smaller stations, where the houses are scattered, a good 

 deal of personal immunity might be secured by attention 

 to this point, in the larger places one would gain but little 

 unless one's neighbours could be induced to do the same. 

 In such places, however, the weekly cleaning out of all 

 such tanks should be made compulsory by municipal 

 bye-law, for in view of our present knowledge it is no 

 more justifiable to foster the multiplication of Mosquitoes 

 than to permit the maintenance of the germs of cholera 

 or other zymotic disease. 



How far care and neatness in cultivation can go to 

 diminish malaria is well shown in the case of Egypt. The 

 climate is well suited to the spread of malaria, the ground 

 water nowhere far from the surface, and the annual inunda- 

 tion of the entire inhabited area would, one would think, 

 render the country a perfect hot-bed of the disease. 



During the actual rise of the Nile, when the whole 

 country becomes a shallow sea, the conditions are no doubt 

 not really favourable to the multiplication of Mosquitoes, 

 but as the waters recede ; but for the fact that the restricted 

 area available for cultivation renders every square foot of 

 value, the conditions are naturally ideally favourable to the 

 spread of the disease. Nevertheless, Dr. Sandwith, of Cairo 

 assures me that, although present, malarial disease is neither 

 common nor serious in the Delta, and a few walks among 

 the fields near Cairo, showed me that the entire cultivation 

 was really of the best garden type, and that land and water 

 were alike regarded by the fellaheen as far too precious to 

 be wasted as sites and material for puddles. 



Celli regards meadow land as unfavourable to the develop- 



