30 ANIMAL COMPETITORS 



resting on the concrete is just as satisfactory so far 

 as the exclusion of rats is concerned." 



Keeping food from rats. The general rat- 

 proofing of buildings is the most important step 

 in limiting the food supply of rats. The effect 

 of an abundance of food. on the breeding of 

 rodents has already been mentioned. Well-fed 

 rats mature quickly, breed often, and have large 

 litters of young. Besides limiting reproduc- 

 tion, scarcity of food will make the measures 

 to destroy the animals by traps, poisons, or 

 bacterial cultures far more effective. But 

 since much of the animals' food consists of 

 garbage and other waste materials, offal of any 

 kind must be so disposed of that rats can not 

 obtain it. The best method is by burning it. 

 The management of slaughter-houses in the 

 country, in particular, needs reform. It is a 

 common practice to leave offal of slaughtered 

 animals to be eaten by both rats and swine. 

 Such places are not only centers of rat-propaga- 

 tion, but are the chief means of perpetuating 

 trichinae in pork. All this should be changed in 

 fact and by law. The offal should be promptly 

 cremated or otherwise disposed of. There is 



