20 MOSQUri'o WOUK IN KHARTOUM, ETC. 



Foi'tunately, in Kh!irtt)uni we have not to dciil A\'itli any swamps, ditches, 

 permanent pools in the streets or near the houses, empty cans, old bottles, broken 

 crockery or other receptacles containing -water for any length of time ; at lejist, 

 there were none such last yeai*. It is possi])le tliat they might have to be 

 considered during a very wet summer, but the rainfall of 1903 was trifling. As 

 a result the laboui-s of the brigade have been limited, and the small staff has so 

 fai- sufficed, ^lajor Ross ' recommends refined peti'oleum or eucalyptus oil for 

 the "training" of well waters, but, after careful enquiry it was deemed better 

 to employ crude petrolcmn, not only because it was cheaper, ])ut because com- 

 paratively little of the well water is used for drinking pm-poses, the nati\-e 

 portion of the population prefemng to use water direct fi'om the Blue Nile. 

 Use of Latter]}', as a considerable quantity of the refined petrolemn had been stocked, 



petroleum 



a 



mixture of crude and refined has been employed. The former appears to be 

 the more efficacious, as it forms a denser fihn and one Avhich lasts lonejer. The 

 well water in Khartoum is for the most part reserved for washing, cooking, and 

 the use of animals. It -was evident that the oiling of the wells would entail 

 some hardship on their owners, but the above fact shows, what indeed proved 

 to be the case, that it could be done Avithout producing any great outcry. The 

 user of an infected and oiled well generally managed to easily satisfy his wants 

 from a neighboui'ing uninfected and untreated water supply. 



Crude petroleum, as stated, is very effectual if properly applied, and, 

 moreover, makes the water so unsightly that none would touch it, and thus 

 there was little risk of any poisoning fi-om water so treated. As a matter of 

 fact, no such accident has been I'eported, and the plan adopted was as follows : — 



The men constituting the brigade began every morning to visit system- 

 atically all the water collections in the to>\ai, beginning on the river front and 

 working backwards day by day till the whole toAvn had been explored. They 

 Avere provided with wide-mouthed bottles for taking samples, and instructed how 

 best to proceed. A cup-shaped apparatus of fine Avire gauze Avas also employed, 

 but the bottles were foimd quite as efficient, especially when the men were made 

 to take three or four samples fi-om different parts of the surface of every Avell 



Mosquito J.11-T1 T 



Brigade work Avatcr Avliere the first dip proA'ed negative. In the case of other Avater collections 

 Durham's larva coUectiug spoon and tin,- recently introduced, have been found 

 to ansAver admirably. In the afternoons, under the charge of Mr. NeAvlove, the 

 men again Aveiit their rounds, the water collections Avere re-inspected, and any 

 found to be infected were thoroughly oiled. In the case of Avells, observations 

 shoAved that in the great majority Ave had to deal Avith a surface area of from 

 12 to 13 square feet. Roughly speaking, about one pint of the crude petroleum 

 was employed per well. This amount was probably in excess of that actually 

 required, but by using it a reUable fihn Avas obtained. Syringes, though good 

 in the case of pools, Avere no use for wells, and it was found best to simply 

 pour the oil straight down upon the water, which, as a rule, was found at a 



' Ross. " Mosquito Brigades " ' Journal of Tropical Medicine, 1/10/03 



