68 SUMMARY OF THE ANTIMALARIAL CAMPAIGNS 



I made a tour of inspection. We first visited some 

 agricultural land plentifully supplied with the irrigating* 

 cliannels characteristic of Egypt. The water in these 

 is supplied from the sweet-water canal, and, as it 

 stands at a higher level, there is considerable fall, 

 circulation can be maintained, and a good head of 

 water can be readily obtained for flushing purposes. 

 Once a w^eek the " Drains Brigade " pays it a visit, 

 cleanses the drains by sending down an extra flood 

 of water, and removes any weeds or accumulations of 

 sand. Constant supervision is necessary to keep the 

 irrigating and drainage channels free from obstruction, 

 as the banks are of sand, and weeds grow rapidly. 

 The least stagnation affords a nidus for the mosquito. 

 The large sweet-water canal does not appear to 

 harbour larva3, the fish to a great extent preventing 

 this. I particularly inquired whether larva? were ever 

 observed in the sea-water canal. I did so because 

 I was surprised to find fresh- water grasses and other 

 fresh-water plants growing along the margin of the 

 canal. The riparian growth of the vegetation is 

 naturally encouraged by the Canal Company, as it 

 is a valuable aid in binding together the otherwise 

 shifting sand of the sides of the canal. No larvae 

 have hitherto been observed amongst the plant growth. 

 ^Ve next drove to an opposite part of the town, w^liere 

 the authorities had nearly completed the filling in with 

 sand of a considerable strip of low-lying marshy land. 

 This will in future ensure the prevention of the 

 formation of any pockets of stagnant water. 



