CONDITIONS INFLUENCING PREVALENCE 167 



children. Further, as will be pointed out further on, the 

 mere fact that Calcutta is a great city, in which municipa- 

 lisation on European lines has been carried much further 

 than in the " up-country" towns mentioned below, is alone 

 sufficient to account for the more crowded portions of the 

 towns which have been provided with a filtered water supply 

 being less malarious than the suburbs, even assuming that 

 Captain Eogers' researches may be taken as conclusive that 

 such is really the case. As a matter of fact, experiments on 

 a very large scale have been of late years conducted in 

 certain Indian prisons, where the entire drinking water 

 supply of the prisoners was carefully and systematically 

 boiled in the hope of diminishing malarial disease, but 

 without producing the least effect in the hoped for direction. 



But apart from this, our experience in Northern India 

 strongly suggests that, so far from diminishing malaria, the 

 introduction of a piped and filtered water supply, has com- 

 monly quite the opposite effect. It is unfortunate that 

 before venturing on generalisation from what appears to be 

 such scanty data. Captain Bogers was not at the pains to 

 avail himself of the tabulated information on this point 

 readily available to him in the annual reports of the Sanitary 

 Commissioners of the Northern Provinces, where the effect 

 of the introduction of filtered water supplies has been a 

 matter of anxious observation for a considerable series of 

 years, for it is impossible to imagine that any diminution in 

 malarial fevers and splenic enlargement could fail to show 

 itself in a diminution of the general death-rate. 



For the benefit of those to whom the above reports may 

 not be readily accessible, the figures bearing on the ques- 

 tion are extracted on next page : — 



The addition of this table to the Sanitary Reports was 

 probably initiated with the view of illustrating the benefits 

 conferred by modern sanitation ; but if this be the case 

 the compilers must have been most disagreeably surprised, 

 for with hardly an exception a rise, and not a fall, of 

 mortality has followed. There are, of course, absolutely no 

 statistics extant of any value whatever as to the absolute 

 number of deaths referable to malaria in any Indian town, 



