No. 4.] RATS AND RAT RIDDANCE. 249 



The use of plaster seems to produce no effect if the amount 

 used is small, while if a larger quantity is used the rats ap- 

 parently do not eat it. But Professor Lantz tells me that in 

 the experiments of the Biological Survey rats ate and. digested 

 freely plaster mixed with flour and meal in varying quantities, 

 and that they also ate without inconvenience pieces of cork and 

 sponge that had been fried in lard. Nevertheless, many people 

 seem to believe that they have secured good results by the use 

 of these methods. 



Others report success with freshly slaked lime placed dry in 

 all burrows and runs, freshly made hot thin whitewash poured 

 in the burrows, and from a strong solution of copperas (ferrous 

 sulphate) sprinkled in runs and burrow entrances. 



Any or all of these proceedings tend to make life uncomfort- 

 able for the rat, and one or the other will reach and defile his 

 domicile under nearly all circumstances. To drive out rats, one 

 after the other of these agents might be used, beginning with 

 chloride of lime or carbolic acid, but the surest way to get rid 

 of rats is to starve them and pursue them with traps and 

 poisons until the last one is dead, or, weary and affrighted, he 

 takes his melancholy way to some more hospitable abode. 



The plan that ordinarily succeeds best in driving rats from 

 dwellings is to get most of them by carefully set traps, and if 

 loneliness and apprehension of evil does not discourage the last 

 one to the point of emigration, a little poison skillfully ad- 

 ministered usually destroys it or causes it to make up its mind 

 over night to depart. 



CO-OPERATIVE RAT KILLING. 



Co-operation in the destruction of rats like co-operation in 

 most other matters is conspicuous by its absence in America, 

 but co-operation is required to abate the rat evil. Under 

 present conditions a farmer, householder or merchant may keep 

 his premises clear of rats, but only through constant effort, 

 because his neighbors make life pleasant for them and allow 

 their increase to wander back to his premises. In England 

 co-operation has made some headway. Rat clubs have been 

 formed, giving prizes or bounties for rat destruction, and so 

 ridding their own communities of great numbers of rats at 



