as Enemies of Mankind. 



trapping operations properly ; on this estimate between 20,000 and 

 30,000 men would be required for such work in Britain. But if 

 the work were properly organized, and one could count on the co- 

 operation of all sections of the community, far fewer men should 

 suffice. Thus, in East Haddingtonshire three rat-killers were 

 employed throughout the year ; each man was allotted a district 

 of from twenty-five to thirty farms, and lived in the centre ; each 

 worked gradually from the boundary of his district towards his 

 home. While the best trappers are usually retired gamekeepers, 

 any man of ordinary intelligence can become proficient with a 

 little training. It is suggested that rat-catching offers a good field 

 of employment for many disabled soldiers and sailors. 



In a general campaign of the kind suggested, the men engaged 

 must be paid by settled wages and not by premiums on the 

 numbers of rats caught. If one pays so much a rat, the rat- 

 catcher will leave a farm as soon as rats become scarce, and before 

 he has finished his work, for another which promises a bigger bag. 

 In a short time the condition on the first farm will be as bad as 

 before. 



2. HOUSE MICE. Genus MUS. 



Only one species of this genus inhabits Great Britain : — 



Mus musculus. The Common House Mouse (Fig. 1). 



Size small ; general form slender — like a Black Eat in miniature. 



Fig. 1. — House Mouse {Mm musculus). 

 (Natural Size.) 



