MAMMALIA 235 



structing a new building it is comparatively easy and inexpensive to 

 make it rat- or even mouse-proof, and in many cities this is enforced 

 by law; in the case of an old building it is often difficult but seldom im- 

 possible to properly rat-proof. In many barns and stables where the 

 expense of rat-proofing the entire building would be prohibitive it is 

 easy to completely cover the feed or grain bins with wire netting; or 

 to pile the bales of hay or sacks of feed on elevated platforms, either 

 supported from the floor as in Fig. 148 or hung from a ceiling that 

 has no rafters along which rats can run. An arrangement such as 

 shown in Fig. 148 not only protects the material but also removes 

 the harbor in which the rats hide and rear their young, one of the 

 most important of the preventive measures of rat extermination. 



In rat-proofing a judicious use of concrete and galvanized wire net- 

 ting will do the work, but both are usually necessary. Many houses 

 are made with rat-proof cellars, but if the cellar windows are not screened 

 rats and mice will soon "make their entrance and the concrete walls 

 and floors have been in vain, so far as rodent infestation is concerned. 

 At a very slight expense the windows and doors can be closed with wire 

 netting of about % inch mesh. Another frequent point of entry into 

 otherwise rat-proof buildings is through or around drain or other pipes. 

 The openings around all pipes should be tightly closed with a mass of 

 cement as thick as the wall. The lower edge of all outer wooden doors 

 should be covered with a strip of tin or other metal about a foot high to 

 prevent rats from gnawing through. 



A frame building with brick or stone foundation, may be made rat- 

 proof by cementing the entire floor of the cellar, screening the windows 

 and filling in the space between the laths and outer boards with concrete 

 to a height of about a foot. Or, a cement wall, starting a couple of feet 

 under ground and extending a foot above ground may be built around 

 the outside wall of the house, as shown in Fig. 149. Porches and small 

 buildings without cellars should be elevated a foot or more above the 

 ground to prevent the harboring of rats and to allow dogs and other 

 rat destroyers to enter. Floors and wooden walks whose timbers are 

 laid directly on the ground are sure to harbor rats. In stables where 

 cement floors are objectionable, wooded floors may be laid directly 

 on the cement. Various methods of proofing corn cribs may be em- 

 ployed. One method is shown in Fig. 150, where is built a concrete 

 wall, sunk about 2Q inches in the ground ? with a concrete floor, upon 



