i6 



Rats a7id Mice 



arge number of the people who throughout the country are 

 brought most closely in contact with the rats, elicited the fact 

 that none thought either of Boelter's premises excessive, while 

 many thought them too low. Dr. Shipley, on the basis of a 

 similar assumption as to the size of the rat j)opulation, estimated 

 the annual damage in Britain at £10,000,000. 



On a later page (p. 60) a table dealing with the rat population 

 of Britain and its expected increase in the current year is given. 

 On the basis of that table we have endeavoured to estimate the 

 minimum loss which will be inflicted upon us this year by rats. 

 In these calculations we have assumed an excessive mortality and 

 waste among the rats ; we allow nothing at all for the mainten- 

 ance of rats not yet capable of breeding ; and we suppose that they 

 will not breed until they are four months old. The cost of main- 

 taining the breeding stock is assumed to be no more than one 

 farthing a day for each rat, but the sum works out to a total of 

 £9,224,000. 



In other countries the annual loss attributable to rats has 

 been estimated similarly to reach huge totals. In Denmark it is 

 said to amount to 15,000,000 francs ; in France the loss occasioned 

 in 1904 was estimated at 200,000,000 francs ; the loss in Germany 

 is officially estimated at 200,000,000 marks ; and in America the 

 Biological Survey estimates that the direct annual loss sustained 

 by residents in the towns and cities of the United States amounts 

 to 20,000,000 dollars, while the total annual damage inflicted 

 throughout the United States is put at 200,000,000 dollars. 



EATS IN EELATION TO DISEASE. 



However estimated, the financial loss occasioned by rats, in 

 wasting our food, materials, and property, must appear colossal. 

 But that loss sinks to insignificance when we consider how grave 

 is the risk of disease entailed by the presence of these pests in our 

 midst. The financial loss directly affects, perhaps, only a com- 

 paratively small number of people, and many of these, ignorant of 

 its extent, are quite indifferent to its cause. The menace to health 

 is real, and it affects every member of the community. In spite 

 of the excellent and unremitting efforts of our Public Health and 

 Port Sanitary Authorities, that menace will last and will grow 

 steadily so long as there is a large and increasing rat population in 

 this country. The list of diseases disseminated by the rat grows 



