738 THE SMALL-MAMMAL PROBLEM 



departments. The Ministry of Agriculture and Fisheries 

 formed a special Rats Branch, and in 19 19 the emergency 

 legislation was embodied, extended, and permanently established 

 by the Rats and Mice (Destruction) Act. 



In view of the importance of this matter, and of the expense 

 and not infrequent hardship, which the proper administration 

 of this Act will entail, it will perhaps not be thought out of 

 place if we discuss some scientific considerations bearing upon 

 the rat and mouse problem. We will in the first place deal 

 with some points of interest in connection with the destruction 

 of rats and mice. Secondly, we will try to show that the 

 problem of the rat and mouse is only one branch of a far greater 

 problem involving not one or two species merely but all small 

 mammals. That greater problem must be solved in the near 

 future, for with the growth of civilisation it confronts us in all 

 parts of the globe. Even so far as Britain is concerned, the 

 Act does not solve the problem, although undoubtedly it is the 

 first step in the right direction yet made by the legislature. 



The Act aims at bringing about a great reduction in 

 the rat and mouse population. It imposes certain obliga- 

 tions upon, and gives certain powers to. County and Local 

 Authorities, the general administration of the Act being 

 entrusted to the Ministries of Health and Agriculture. 

 County Rat Officers have been appointed for the purpose of 

 putting the Act into practice ; and the owner or occupier of 

 rat-infested premises is now compelled to free his premises 

 from infestation and to put his house in order. All this is 

 good and should lead to a rapid improvement in existing 

 conditions ; and from the Rat Ofiicers we may hope to obtain 

 a great deal of information. 



The high fecundity of our parasitic rats and mice 

 makes it very difficult or impossible to exterminate any one 

 of these species by methods of active destruction alone. The 

 best information, at present at our disposal, concerning the 

 breeding rate of any of the three species inhabiting Britain 

 is that furnished for R. norvegicus by Petrie and Macalister.^ 



• Petrie and Macalister in " Reports and Papers on Suspected Cases of Human 

 Plague in East Suffolk and on an Epizootic of Plague in Rodents." Reports to the 

 Local Government Board on Public Health and Medical Subjects, N.S., No. 52. 

 London 191 1, p. 58. 



