NATIONAL ASSURANCE 88 



matter will be sifted, and perhaps trouble will ensue. 

 But if the scheme is a proved success and the expendi- 

 ture justified by adequate dividend no questions will 

 arise, for the results are obvious. With fly-reduction, 

 however, the results cannot always be obvious. There 

 are several reasons for this. The fly-population is, as 

 has already been stated, directly related to climate. 

 Flies may be a pest one year and almost absent the 

 next. Therefore, the incidence of fly-borne disease 

 varies from year to year. Consequently, it may be 

 very difficult to say whether the reduction of fly-borne 

 diseases in any one locality during any one year is due 

 to organised fly-reduction or to variation of the climate. 

 People may say that the reduction of fly-borne diseases 

 is due to the milder summer .and not to the anti-fly 

 campaign, and the money spent has been wasted. 



Yet such is not the case the money is not wasted. 

 The expenditure has placed the community, so far as 

 flies are concerned, beyond the influence of vagarious 

 weather ; and should it be hot or cold, dry or rainy, if 

 the anti-fly campaign is efficient there is the certitude 

 that the campaign is successful and that the fly-borne 

 disease will not appear. In other words, the money 

 spent is the premium of an assurance policy. This is 

 the light in which all public-health expenditure should 

 be regarded. In sanitary matters the public is its own 

 insurance company insuring itself against death ; and 

 in trying to prevent unnecessary death it is saving its 

 own pocket. 



Suppose that after a few years of fly-reduction the 

 figures show little or no reduction in fly-borne-disease 

 mortality. What is to be done then ? The cause of 

 the discrepancy should be found out. Perhaps the 

 statistics as obtained at the outset were fallacious. Or 



