64 Report of the Bilharzia Mission in Egypt, 1915 



of Planorhis boissyi were common in the marshes and ditches there 

 and were found harbom-ing developmental stages of bilharzia type. 

 Marshes, which usually occupy low-lying areas and derive their 

 water in part from seepage, can only be dealt with adequately by 

 filling. The value of the land reclaimed should compensate for 

 this necessary outlay. Moreover, these marshes are the main 

 breeding-places of malaria-bearing mosquitoes, and on this account 



Fig. 29. — Filling marsh at Ismailia. 



alone their abolition is called for even at some cost to the State, 

 as shown in the accompanying photograph (fig. 29). The marshes 

 near Ismailia which were found to be a possible source of danger 

 on account of bilharziosis are being rapidly filled in as an anti- 

 malaria measure in completion of Sir Eonald Ross' recommenda- 

 tions for the protection of Ismailia. 



Prevention of Bilharziosis in Agricultural Districts. 



Whereas the essential condition to the prevention of bilharziosis 

 in towns was found to be the destruction of the free-swimming 



