X 



Introduction. 



unmerited share of the world's foodstuffs, together with perfect 

 travelhng facihties. Small wonder then that these creatures have 

 invaded and colonised all lands, including those, like North and 

 South America, which possess no native true rats or mice ; that 

 they have developed into serious pests, taking a heavy toll from 

 human prosperity, and forming a most deadly menace to the 

 public health. 



The objects of this pamphlet are to give a brief account of 

 these noxious animals, their habits and breeding; to deal with 

 their economic importance and relations to the public health ; and 

 to suggest measures by which they can be controlled, if not 

 exterminated. 



I would take this opportunity of thanking Dr. S. F. Harmer, 

 F.R.S., and Mr. W. P. Py craft for much assistance and advice. 



