I208 



THE MALARIAL FEVERS 



A. Engineering works intended to eliminate breeding places: — 



1. Draining swamps. 



2. Draining roads. 



3. Filling in hollows. 



4. Training streams. 



. 5. Making continuous drains along ravines, etc. 



6. Planting trees at intervals, not close together (this is 



both ornamental and useful), or the thinning down 

 of dense plantations until the trees are at intervals, 

 and the removal of trees with rot-holes, which, how- 

 ever, may be filled. 



7. Segregation either of the whole community, by altering 



the residences from some very infected area or partial 

 segregation of a chosen portion of the community 

 from the worse-infected portion. Simpson recom- 

 mends that at least a zone of 300 yards in width, 

 preferably 400 yards, should separate the residential 

 European quarters from the Native town. Since 

 segregation has been introduced in West Africa, a 

 considerable improve ment in the health of the Euro- 

 pean community has taken place. 



8. Efficient drainage to keep down subsoil water-level. 



B. Sanitary works : — 



1. Removal of small collections of water. Regular in- 



spection of compounds and careful collection and 

 disposal of household utensils likely to harbour 

 mosquito larvae. Repair of house gutters. 



2. Oiling collections of water with kerosene (crude petro- 



leum) by means of sprays every ten days, i gallon 

 ' being allowed for 1,000 square yards. 



3. Larvicides. — ^Measure the length and breadth of the 



area of water and add i in 20,000 to i in 50,000 

 sanitas okol or i in 40,000 izo-izal, or the Panama 

 disinfectant. 



Wise and Minnett have recommended that i ounce of crude carbolic acid 

 be added to every 16 cubic feet of water, thus giving a dilution of i in 16,000, 

 which they maintain will kill the larvae without injuring any animal which 

 might happen to drink the water. 



4. Screening -wells, cisterns, cesspits, etc., with wire gauze. 



5. Removal of plants likely to contain water and act as 



breeding-places (the following may be specially noted 

 bamboos, pineapple plants, travellers' palms, fibre 

 plants). Water-weeds in streams should also be 

 removed, as the larvae are often found to be protected 

 by these against 'their natural enemies. Water- 

 weeds should be removed before oiling. Brush and 

 grass should be cut. 



6. Introduction of fish, especially ' millions,' into collections 



of water. 



