May, 1909.] 447 



MISCELLANEOUS PESTS. 



"THE RAT PROBLEM." 



Tuei e are, no doubt, many people, both 

 in the scientific and commercial worlds, 

 who are at present quite unaware that 

 rats are in any way connected with a 

 problem. Mr. Boelter, however, is con- 

 vinced about the matter, and in the 

 book now before us has taken up the 

 case for prosecution of the rat in such 

 a way that all those who read this 

 book will be bound to pass a verdict 

 very derogatory to the rat, in spite of 

 what may be said by those who argue 

 that every animal has his useful part 

 to play. 



The first chapter is devoted to the 

 natural history of rats. The brown rat, 

 which has nearly replaced the old black 

 rat, was probably introduced into 

 England in 1732, and now it is quite safe 

 to say that we have over 40,000,000 in 

 our islands. A diagram illustrates in a 

 very clear way how the brown rat has 

 gradually established itself in most parts 

 of the world. Man has been the means 

 by which they have emigrated, and in 

 this direction it may be remarked that 

 civilisation has done a great deal to 

 upset the balance of Nature and to 

 establish many plagues and diseases. 

 The illustrations are old and familiar, 

 ind it is probable that photos would 

 have been better nowadays. Consider- 

 ing the way in which vernacular names 

 may mislead people who are not acquaint- 

 ed with the habits of our wild animals, we 

 should have liked to have seen a little 

 more written about the water-rat. This 

 animal does not belong to genus "Mus" 

 (true rats), but to genus "Arvicola" 

 (voles), and it is to be hoped that the 

 commercial loss caused by the ravages 

 of the brown rat will not be heaped on 

 to the back of the water-vole. 



The second chapter is devoted to the 

 loss caused by rats, and the legendary 

 Pied Piper of Hamelin is mentioned. A 

 circular has been issued by the Incor- 

 porated Society for the Destruction of 

 Vermin, and the replies given to various 

 questions by farmers, poultry farmers, 

 gamekeepers, drapers, grocers, hotel 

 proprietors, warehousemen and horse- 

 owners are most convincing. The above 

 Society, with Sir James Crichton Browne 

 as its president, hope to b^ing into 

 operation a rat law similar to that 

 formed by Zuschlag and his society in 

 Denmark. The annual loss caused by 

 rats is estimated at £15.000,000, and 



besides that they are the means of 

 spreading trichinosis and the plague. 



The fourth chapter is devoted to the 

 means of the extermination of rats. 

 The part played by the owl, weasel and 

 kestrel as natural enemies of the rat are 

 described. It is, of course, a great pity 

 that these useful animals are so perse- 

 cuted for things which they very rarely 

 do. A very interesting biological law is 

 brought out in this chapter by the 

 story of an old ship's mate who used to 

 catch a dozen or so rats on his ship and 

 then kill all the dozen and give them to 

 the bucks to eat. These were then 

 released. By this means he used to 

 keep his rats at a minimum, and the 

 process had to be repeated in about six 

 months. For the welfare of most 

 mammals it is necessary that the female 

 population should be in excess of the 

 male, If, however, the conditions are 

 reversed, then -breeding females and 

 their litters are upset, and if this process 

 were continued long enough the species 

 may be exterminated, This has been 

 applied to some districts in Australia 

 with regard to rabbits and found to be 

 a great success. 



The various mechanical means of 

 catching rats is considered, and the Old 

 Royal Rat Catchers' works are quoted. 

 Under man's care the cat has given up 

 the chance of being bitten for a more 

 homely saucer of milk. Phosphorus, 

 strychnine, arsenic, sulphate of calcium, 

 and one or two other bases of the 

 common rat poisons are reviewed in a 

 most satisfactory manner. 



Of the bacterial preparations it is 

 interesting to note that the bacillus 

 discovered by Newmann in the urine of 

 a two-year-old child appears to be the 

 most efficacious. It is the active prin- 

 cipal in Ratin. Danysz' preparation 

 and the Liverpool virus are not spoken 

 of so favourably. It has to be re- 

 membered, however, that Xylander, 

 whose works are very reliable, consi- 

 dered microbic rat poisons at present 

 (1908,) as being far from safe and reliable. 



Chapter V. contains a few of the more 

 important conclusions arrived at in the 

 first four chapters, and the chief rea- 

 sons given to account for the prevalence 

 of the rat are as follows : (a) Its physical 

 and mental faculties, (6) its great fecun- 

 dity, (c) the increase of human popu- 

 lation, (d) the killing of the rats' natural 

 enemies, and (e) the total absence of 

 co-operation in the methods chosen by 



