METHODS OK KAT UESXUUCTION. 231 



That it may also be iised with some success in fumigaiing rat- 

 holes in the open. 



In connection with the above conchisions I have the following 

 ■observations and recommendations to make : — 



(«) Owing to rats when active measures are taken ngainst 

 them frequently migrating to neighbouring farms and estates, 

 co-operation in their destruction is imperative, and the whole of 

 ■ji rat-infested area should be treated on the same day, and not in 

 parts at different times as is at present generally done. 



(b) A rick surrounded by 5^ feet high galvanized iron sheetings 

 dng 2^ feet into the ground, is just as effectually protected, and 

 at a much smaller cost, than when built on a massive non-portable 

 staddle. 



(c) At present the giving of rewards for rat-tails is indulged in 

 by some and not b}^ others. As those who do so cease when they 

 •discover they are called upon to pay foi' their neighbours' rats, 

 the payment of such rew^ards should be made compulsory for all 

 •employers, at any late during the winter months when scarcely 

 -any young are about, Imt when every adult at this time repre- 

 sents a potential increase in the nmubers for the near future. 

 This would go a long way tow-ards keeping the vermin in check. 



(<Z) In view of the recent undoubted increase in the numbers 

 •of not only the Common Brown Rat but also the Old English 

 iJlack Rat, all ships should at regular intervals be subjected to 

 treatment Avith Sulphur Dioxide gas by means of Sulphur 

 "Candles or a Clayton or some similar ajDparatus. 



(e) The formation of a research school in the country, where 

 further experiments on i-at-destruction could be continued 

 throughout the jear, is desirable. That at this school the various 

 poisons recommended should be made up and supplied dii'ect to 

 the rat-officers appointed by the County authorities; such officers 

 being from time to time required to attend a course there, and 

 be made acquainted with the latest developments. 



It should be borne in mind that our investigations were con- 

 -ducted at a time of the year — May to September — when plenty 

 ■of food is available for the rats, and that some of the methods 

 Avhicii resulted in failures Avould possibly have succeeded if 

 ^ipplied during the winter months. 



The successes obtained deserve therefore, I think, special 

 'Consideration. 



We i-ealized that the fiirst step towards finding an effective 

 method of rat-destruction, whether by means of poisons or traps, 

 •was to ascertain what baits the rodents found most attractive, as 

 no device dependent on food being taken could, however ingenious, 

 -otherwise prove a success. The baits referred to in the table 

 below were given to rats in captivity and in the Avild state, and 

 were nearly all put down together on o\'er fifty different occa- 

 sions. In the case of the rats kept in captivity, the animals 



