^H. IX] QUININE PROPHYLAXIS 153 



transmission to have been very thoroughly studied and the 

 whole area accurately and thoroughly surveyed. 



Of measures mdirectly affecting the prevalence of Anopheles, 

 the most important are " drainage " and " agriculture." The 

 dramage of marshes, lakes, etc. has long been known to have 

 a favourable effect upon malaria. Agricultural operation, by 

 which waste lands are reduced to the condition of tilled fields, 

 is another general measure having a very definite influence 

 upon malaria. Both these measures, though they do not aim 

 directly at mosquito reduction, bring about this result indirectly 

 by lowering the level of the subsoil water, lessening humidity 

 and so forth. A measure of this general kind, which may 

 assume importance under certain circumstances, is protection 

 against flooding. It has recently been shewn that some of 

 the worst manifestations of epidemic malaria follow in the wake 

 of floods, arising from the overflowing of rivers and swollen 

 mountain torrents. In such cases various engineering devices 

 may be important anti-malarial measures of this general kind. 



2. Where preventive action against malaria takes the 

 form of attacking the parasite in the human host it usually 

 consists of some method of quinine prophylaxis. In the 

 method advocated by Koch an attempt is made to sterilize, 

 as far as the malarial parasite is concerned, the blood of every 

 member of the community by systematically searching out 

 and treating every infected person. The method to which the 

 term quinine prophylaxis is generally applied, is one in 

 which as many of the community as possible are persuaded to 

 take quinine regularly and systematically. Where large and 

 at the same time poor and ignorant populations are concerned, 

 it has generally been found impossible to apply either of the 

 above measures sufficiently thoroughly to be effective, and it 

 is now recognized that under these circumstances the greatest 

 benefits are obtained by treating the sick and encouraging in 

 every way the use of quinine in its curative rather than its 

 prophylactic capacity. This method is usually designated as 

 quinine treatment of the sick. Though directed especially 

 to the saving of life, it has been found also to have a general 

 influence upon malaria. 



