May 20, 1922] 



NATURE 



659 



The Rat and its Repression. 



By Alfred E. Moore, Hon. Director of the Incorporated Vermin Repression Society. 



R^ 



ATS have for more than three thousand years 

 been regarded as noxious vermin by man. 

 Boelter ^ reminds us that the Egyptian cat, F. 

 Caffra {Caligata or Maniculata) was a domestic 

 animal in Egypt twenty centuries b.c. and that it 

 was held in the highest reverence as a natural pro- 

 tector of grain from rats and mice. Boelter relates 

 how, when Ptolemy was doing all he could to conciliate 

 the Roman power, a Roman accidentally killed a cat, 

 and Diodorus Siculus, an eye-witness, tells how 

 nothing, not even the terror of the Roman name, 

 could save the unlucky Roman from punishment. 

 To-day, when the rat army numbers almost countless 

 legions, we find an apathy that is appalling, a stagna- 

 tion of effort which is allowing the rat to encircle 

 the earth, and like a creeping paralysis to leave death 

 and destruction in its trail. 



It is not so important to fix geographically or 

 historically the origin of the rat, as it is to realise the 

 fact that this rodent now inhabits practically every 

 place where man has a dwelling, and that of all 

 animals it is most fitted by nature to serve as a 

 human scourge. Apart from the astonishing pro- 

 lificacy of the rat, the animal is furnished by nature 

 with first-class engineering and excavating tools 

 in the shape of wonderful hand-like paws, a pair of 

 incisor teeth of razor-like cutting power and hard- 

 ness, a tail which serves a variety of uses, and a 

 brain nimble, cunning, and educable. These ad- 

 vantages plus a courageous and adaptable disposition 

 have served to make the rat ubiquitous. 



It has been urged that all rats are cannibals and 

 that the brown rat {Rattus Norvegicus) in England 

 has driven out the black rat {Rattus Rattus), but 

 too much reUance cannot be placed on these 

 assumptions, for rats are cannibals only when 

 driven by unsatisfied appetite, and it is doubtful 

 if the number of black rats in any area in England 

 is such as to diminish the food supply of the brown 

 rat and force it to become an active cannibal, or, on 

 the other hand, that the sexual appetite artificially 

 stimulated under the Rodier system can diminish 

 appreciably the number of rat hordes. 



It is, of course, fairly easy to invite a charge of 

 exaggeration when dealing with the rat, for the pest 

 is without doubt a grave menace ; it has been 

 said by Dr. Khunart that the rat must be destroyed, 

 or it will destroy man. Insistence on the serious 

 character of the problem makes it extremely difficult, 

 however, to wage an effective war on the animal; 

 for it is easy to secure the label " crank " and to 

 lead the man-in-the-street to remark that, if it be 

 true that the rat is such a terrible fellow, " it's a 

 wonder we are alive." Prominent leaders of thought 

 in the veterinary world regard the rat as a disease 

 carrier par excellence, and I am convinced that further 

 research will estabhsh the rightness of many suspicions, 

 but for the moment let us consider the nature of 

 proven charges. We know, for example, that rats 

 transmit plague, trichinosis, malignant jaundice, 

 parasitic mange, and rat-bite fever, and we know 

 that these maladies are serious diseases. They are, 

 of course, calculable in effect, but there are other 

 human ills directly attributable to the presence of 

 the rat, such as loss of sleep through nervousness, 



' "The Rat Problem," by Wni. Boelter. John Bale, Sons, and 

 Danielsson, Ltd. 



NO. 2742, VOL. 109] 



fright, etc., and these ills are burdensome in so far 

 as that they contribute materially to the sum of 

 factors in physiological fatigue and therefore occasion 

 incalculable loss of human efficiency. 



Economically, the rat is a charge upon the resources 

 of the nation, which is only measurable in figures too 

 great to be comprehended by the casual student. 

 We know that rats commence to breed when three 

 months old, that the female litters from 6 to 12 

 times a year, and that the litter consists of from 

 6 to 12 young ; therefore, we have a population of 

 about 1000 rats from one pair of rats in 15 months, 

 and as a rat costs approximately i\d. per day for 

 food it will readily be seen that we are paying 

 too dearly for this pest. How much we are paying 

 will be more clearly realised when we remember 

 that it is generally agreed that the number of rats 

 equals the human population ; in some cases the rat 

 population is considerably greater, as at a sugar 

 plantation in Porto Rico, where the population 

 numbered less than five hundred people and a six 

 months' rat drive accounted for 25,000 rodents 

 killed. Bearing these numbers in mind, and taking 

 the population of the British Isles as being about 

 47,000,000, we get a rat cost of as much as 75,000,000/. 

 per annum after deducting \d. per day per rat for 

 garbage eating. 



This is not, however, the total amount of taxation 

 the rat imposes upon us, for it is my experience 

 that the animal does an enormous amount of damage 

 in pursuit of its food, and in poultry yards its 

 depredations are very considerable. " Lantz (U.S.A.) 

 quotes a Washington merchant to the effect that 

 rats gnawed a hole in a tub containing 100 dozen 

 eggs, and within a period of two weeks carried away 

 71 dozen without leaving either shell or stain." 

 Cases are not rare where rats have disposed of half 

 a lamb in a night, and it is an undoubted fact that 

 if meat is condemned as tuberculous or unfit for 

 food, rats seem to have an uncanny instinct for 

 finding and consuming such portions of the carcases 

 as are diseased. 



It must not for one moment be imagined that fear 

 of the rat is a fad, nor is it peculiar to the medical 

 profession : medicine, hygiene, and commerce all have 

 contributed men with international reputations — 

 Crichton-Browne, Andrew Balfour, Arthur Shipley, 

 Glen Liston, Mark Ho veil. Akin, Pasteur, Cieel, 

 Emil Zuschlag, Hinton, Bruce Bruce-Porter, James 

 Cantlie, Frederick Hobday, Banister Fletcher, Castel- 

 lani, Nathan Raw, Sydney Hickson, Tanner Hewlett, 

 and Lords Denbigh, Aberconway, Lambourne, Ernie, 

 and others too numerous to mention have joined their 

 voices to those of the informed public and members of 

 Parliament in a call for rat repression, as a measure 

 of pubUc safety. 



It is significant that the first determined effort to 

 deal with the rat in England found definite shape in 

 ordinances made in various parishes in 1740 and again 

 in a Bill introduced into the House of Commons by 

 Sir Chas. B. McLaren in March 1909, and reintro- 

 duced by him into the House of Lords, some ten 

 years later, where he sat as Lord Aberconway. 

 Although in common with America, Japan, Den- 

 mark, Sweden, Barbadoes, Antigua, and Hong Kong, 

 we in England have now an anti - rat law, there is 

 much amendment required to make it effective. 



