HYGIENE 535 



(lo) In the event of an engine or jDump breaking down, particular 

 care should be taken to deal with stagnant pools, and petroleum 

 should be used where necessary. 



(ii) Malarial fever and excessive numbers of mosquitoes should 

 be notilied to the Governor of the province by the manager of the 

 concession. 



Rice-bearing ground must be closely watched and well controlled 

 lo avoid mosquito breeding, otherwise cultivation decreases the 

 healthiness of the soil. 



Ground air must be cut off from tropical dwellings by having a 

 basement or foundations in cement or other impermeable material. 



Loose sand mav contain 50 per cent, of ground air. 



Ground air contains moisture, organic matter of animal origin, 

 sometimes of vegetable origin, also, in consequence, ammonia, 

 hydrogen sulphide, marsh gas and carbon dioxide in excess. 



The ground air is in constant movement as a result of the wind, 

 percolation of the rain, varieties of temperature and barometric 

 pressure, also by the rise and fall of the ground water level. 



Organisms exist in the soil in abundance, nitroso bacteria (nitrous 

 organisms), nitro bacteria (nitric organisms). These are found within 

 I J inches of the surface. B. tetanus is world-wide. B. anthracis, 

 bacillus of malignant oedema and B. typhosus may survive twenty 

 weeks in the soil. The B. coli exists in the soil, but for shorter periods. 



CONSTRUCTIONAL HYGIENE. 



Building Site. 



In selecting a site for a house, choose the side of a hill awa}' from 

 the native quarters and secure natural drainage. 



Tablelands are always good. Avoid all depressions, feet of hills, 

 ravines and narrow valleys. Avoid a luxuriant fertile soil which 

 means dense vegetation. What is good for vegetation is bad for man. 

 Select a dry site, granite if possible; " build your house upon a rock." 



Good water should be accessible. 



Clear all bush for 200 metres from the nearest dwelling. Leave 

 high trees. Plant Bahama or Kasai grass, but keep it cut short or 

 it will harbour mosquitoes. 



There should be a slope from the house in all directions if possible, 

 with small, shallow, open drains to carry off the water. 



The House. 



Mosquito-proofed brick houses, raised from the ground, \\\{\\ a 

 broad verandah are most suitable for the tropics. 



The rooms and verandahs should be ceiled to form a ventilated 

 air space under the roof. The rooms should be lofty and boarded. 



34 



