66 Beport of the BilJiarzia Mission in Egypt, 1915 



cercaria, in country districts water in small canals, shallow 

 ditches and irrigated fields is so general and there are certain 

 agricultural appliances (such as those illustrated in fig. 30 and 

 fig. 31) which necessitate continual exposure to infected water in 

 such common use that other preventive measures must be found. 



Fig. 32. — Iron pipe in the course of the Marg Canal regulating amount of flow. 



Government Control of Nile Water. 



In those areas enjoying the privileges of perennial irrigation 

 the water is not allowed to run indiscriminately. The supply is 

 carefully husbanded and is entirely under the control and constant 

 supervision of the Irrigation Department. The irrigation outlets 

 from the pubHc canals are furnished with iron pipes of a definite 

 diameter so that the amount of water passing shall bear a calculated 

 relation to the area served (fig. 32). 



During the summer months the water in the canals is controlled 

 by the periodical closure of the head regulators for definite periods. 

 These times are officially announced by the Government. A copy 



