Vol. XVI. No. 396. 



THE AGRICULTURAL NEWS. 



207 



RATS AND THEIR EXTERMINATION. 



With reference to the report of the select Committee of 

 the House of Assembly appointed to consider the que.stion 

 of taking measures (or the exterminating and reducing of the 

 number of moniioose in Barbados, it is well to bear in mind 

 that the reason for the introduction of the mongoose into the 

 West Indies was to get rid of the rats which were cau-sing 

 serious depredations in the cane fields, to consider, if the 

 mongoose is exterminated, what will be the results of the 

 comparative immunity enjoyed by the rat, and to inquire 

 more carefully into other methods for coping with these 

 pests. 



The rat is found closely hut discreetly attaching himself 

 to man through the instinct of knowing that food and water 

 are to be fouud near the latter's dwelling, and man, on the 

 other hand, recognizing the nuisance caused by the voracious 

 appetite and thirsty nature of the rat, has responded by vain 

 endeavours to rid himself of his unwelcome guest. The rat 

 is obnoxious to man for many reasons, some of which have 

 only lately become known owing to the recent advances 

 of medical science. Rats are omnivorous, and the loss 

 caused by their depredations is not confined to the foal 

 they eat, but extend.s to the food they spoil and the 

 damage they cause by gnawing through such structures 

 as wooden partitions in search of food and water. But the 

 actual damage caused by rats is endurable when compared 

 ■with the disease they assist in spreading throughout the 

 world. The rat, long suspected of being concerned in the 

 spreading of the plague or black death, is definitely found 

 guilty by modern science of acting as the host of the plague- 

 flea, while it has also been proved that trichinosis is also 

 spread by this rodent. From feeding experiments with 

 wild rats it has been found that the economic damage to food 

 and material in Great Britain probably amounts to 

 £15,000 000 annually. In the United States Public Health 

 Reports of 1913, it will be seen that a stage has been reached 

 at which, knowing the history and habit of the brown rat, we 

 may consider the best means of coping with the pest under 

 the following heads: — 



Preventive means; (1) rat-proof construction: (2) adequate 

 protection of water and food. 



Curative means: (1) frightening: (2) destructive — (a) 

 natural enemies, (b) traps, (c) poisons. 



im;eventive me.\ns. Many kinds of structures formerly 

 made of wood are now constructed with cement, and when 

 the.se buildings have an efficient concrete foundation, an 

 effectual barrier to the ingress of rats is imposed. The 

 screening of basement windows with wire netting, the 

 furnishing of all drain pipes with traps and gratings, and 

 the elimination of all means by which rats can climb and 

 obtain access to buildings must be accomplished if the 

 cunning animal is to be battled. 



Keeping anything which may serve as food for rats in 

 ^a^p^oof receptacles, is one of the surest methods of dis- 

 couraging their presence in buildings. The rat is known to 

 be a very thirsty animal and cannot live long without water, 

 and, from experiments conducted by the United States 

 public health officials, it was found that rats in the majority 

 of cases live only from three to fifteen days on wheat without 

 water, but with foods containing much water such as carrots, 

 the animals were alive thirty days after the commencement 

 of the experiments. The necessity to rats of water or 

 watery foods is one of the guiding principles in maintaining 

 free from rats warehouses and other buildings containing 

 food. 



ijURATiVE m:;asuue.s Although a rat is not easily 

 frightened, it nuy be desirable to place in its runs or 



burrows one of the following substances: freshly slaked lime, 

 dry, or as a thin whitewash; a strong solution of ferrous 

 sulphate (copperas); chloride of lime; gas-tar; powdered 

 red-pepper; or caustic potash. 



In the West Indies, except the mongoose and snakes, 

 there are no natural enemies of the rat among the wild animals 

 and birds. 



Trapping is an effective method to reduce the number of 

 rats, but it requires considerable knowledge to meet the cun- 

 ning of the wily rat, while precautions have to be taken in the 

 employment af poisons in their extermination. The latest 

 form of poisoning is that of spreading disease among rats by 

 prepared bacterial cultures. But all these methods for the 

 destruction of these vermin will be futile unless concerted 

 action is taken by the whole community, for the rats in one 

 area are likely to migrate to another and so escape. 

 Stringent measures to develop immunity, as well as to 

 prevent fresh colonies of rats being landed by visiting vessels 

 must also be taken. 



TRADE BETWEEN CANADA AND THE 



WEST INDIES. 



The report of the Department of Trade and Commerce 

 of the Dominion of Canada for the fiscal year ended 

 March 31, 1916, possesses special interest for West Indian 

 readers, affording as it does an opportunity of seeing the 

 results of the war and of the reciprocal trade relations entered 

 into by Canada and the West Indies under the terms of the 

 Preferential Tariff Agreement signed at Ottawa in 1912, 

 which was the outcome of the Commission under the 

 Chairmanship of Lord Balfour of Burleigh. 



From the report it appears that in the period of five 

 years ended 1916, the total Canadian exports and imports to 

 and from the West Indies have been; — 



Value of 



Imports. 



5,3i5,861 

 G,05S,959 

 4,484,9i4 

 6,039,595 

 6,355,785 



It will thus be .seen that the total trade between the 

 Dominion and the West Indies has, during the period in 

 question, increased from 89,580,286 to 610,490,686. 



The chief article imported from Canada into the West 

 Indies was wheat flour which, in 1912, was in value 

 .$1,595,986, in 1915 .$2,340,259, and 1916 12,074,670. 



The values of the chief articles of West Indian produc- 

 tion imported, in 1912 and 1916, into the Dominion were:^^ 



1912. 1916. 



Cacao 85,265 365,249 



Coco-nuts 81,751 27,436 



Bananas 14,495 



Limes 1,051 107 



Oranges ] 



Shaddocks - <50,720 43,213 



Grape-fruit ) 



Lime juice (crude only) 14,979 23,655 



Rum ■ 18,5SL 22,043 



Sugar and molasses, duty 3,980,161 4,463,257 



Sugar and molasses, free 1,080,721 999,615 



