159 



is limited chiefly to warehouses, elevators, and ship holds. They 

 are deadly to rats in the same way that they are fatal to every sort 

 of life. Many difficulties and some dangers stand in the way of 

 their use. It is safe to advise that no one unacquainted with their 

 action should ever employ fumigants. 



NATURAL ENEMIES. 



The war upon rats carried on in San Francisco has proved the great 

 value of cats and dogs as natural enemies of the rat. That city now 

 has a law requiring all structures of 800 or less square feet and outside 

 certain limits to be raised high enough above the ground to allow 

 access to cats and dogs. (All other buildings in the city must be rat 

 proof.) An index to the worth of rodent foes in their extermination 

 points from what happened during the great London plague. At 

 that time the disease was supposed to be air carried ; any furry mate- 

 rial might hold and spread infection. The magistrates decreed that 

 all cats and dogs should be killed to prevent plague from lodging 

 and traveling in their hair. Rats were thus free to live and breed un- 

 molested, and live and breed they did until the plague killed them off; 

 then and then only did the disease cease its ravages among human 

 beings. 



DOGS. 



Slight training will make excellent ratters of Fox, Irish, or Scotch 

 terriers. Fox terriers have proved especially valuable as retrievers 

 when shooting squirrels, which in one case out of five will escape to 

 their burrows unless sharply retrieved^ 



CATS. 



Cats are little less valuable than dogs against rats, while they are 

 useless against squirrels. The ordinary cat is too well fed to attack 

 large rats and goes, almost solely, after mice., 



All other animals naturally preying upon rodents class with wild 

 life- weazels, ferrets, badgers, skunks, and minks. These can be used 

 only in country places, where, however, their raiding of chicken coops 

 tends to counterbalance their value as ratters. The skunk alone is 

 an infrequent slayer of fowl, whereas he harvests innumerable farm 

 pests from worms to crickets. Yet an insurmountable prejudice 

 against skunks stands in the way of realizing his full usefulness against 

 rodents. In addition, various hawks and most owls kill off rats. 

 Since rats come out chiefly in the nighttime, owls have the better 

 chance to be serviceable in their destruction. The efficiency of these 

 birds in rural districts quite equals that of a dog against rats, while 

 besides dogs we have not as yet found a safe natural foe of ground 

 squirrels. 



