THE EAT PROBLEM 



175 



suffer likewise from their attacks. Finally the rat is the 

 orimary boast of trichina which causes so much damage and 

 oss in the raising of swine. One of the prime requisites in 

 ;ill such industries, if they are to be conducted with safety 

 ;md success, is rat-proof construction. 



The depredations of rats on fruits and vegetables, bulbs and 

 seeds of all kinds, and all manner of merchandise, meats, and 

 stored provisions are too well known to require more than 

 passing mention. Buildings are damaged, water pipes gnawed 



FIG. 84. A small night's work for a rat 



Eleven chicks have heen killed and dragged into the hole and three bitten so that 

 they died. Photograph by the author 



;ind buildings flooded, the insulation of electric wires de- 

 stroyed, which, together with matches carried into their nests 

 ;md ignited, cause numerous fires. " It is conservative to place 

 the entire yearly loss to the people of Washington from rats 

 ;md mice at $400,000 " (Lantz). For Baltimore, Lantz esti- 

 mates the yearly damage at $700,000 ; and for cities in the 

 United States of over 100,000 inhabitants these studies would 

 indicate an annual loss of $20,000,000. 



Black death, the bubonic plague, beginning in China in 

 1334, swept westward over Europe, and in that single epi- 

 demic killed, it is estimated, 25,000,000 people in Europe 



