A rat census can never be taken; but, estimating that there is one rat for every human being on these islands, or less than one rat for every acre of ground, a moderate estimate would give us 40,000,000 rats at any one time. It has been calculated that a rat does at least 7s. 6d. worth of damage during the course of the year: hence in Great Britain and Ireland, we may annually charge them with a loss of at least £15,000,000!
From what has been said it is obvious that rats cause enormous damage to humanity, which is counterbalanced by the almost infinitesimal good they do as scavengers. I do not propose to consider in detail the harm they do as disease-carriers, but one cannot forget that the rat is the primary host of Trichinella spiralis, which, when conveyed from the rat to the pig, and—by eating uncooked or imperfectly cooked pork—from the pig to man, causes severe and very fatal epidemics, and enforces the expenditure of large annual sums on meat inspection. They further convey a virulent form of equine influenza from one stable to another, and also the ‘foot-and-mouth’ disease. But what is infinitely more important to man than all the other injuries put together is the harm they bring to suffering humanity by conveying the bubonic plague from one patient to another. The plague under which India and great parts of Burma are ‘groaning and travailing,’ is caused by a specific bacillus discovered in 1894 by Yersin at Hong-Kong. It flourishes in other vertebrates besides man and the rat, but, owing to the migratory habits of the latter, the rat is the most effective agent in the spread of the disease. Both species of rat seem about equally susceptible, and the presence of the microbe showed no special relation to either the age or the sex of either species. The microbe is conveyed from rat to rat and from rat to man by a flea.
The destruction of the rat is now being urged on all hands, and in the near future we shall probably see a considerable diminution in their numbers in the more civilised countries of the world. This will mean a considerable upset in the balance of power of the almost hidden fauna which surrounds us on all hands. It may even, as the Medical Officer of Health for Bristol has pointed out, lead to an increase of immigration of ship-rats—those most likely to be infected by plague—to take up the places vacated on land by the slain. By one of those commercial agencies—I do not propose to go into the merits of any one of them—which the enterprise of our merchants is now pressing on the public, a large landed proprietor a few months ago completely freed his buildings of rats and mice. A few weeks later his house and out-buildings were overrun by swarms of what to him—for in the time of the rats and mice he had never seen one—was a new and formidable insect. He sought the aid of the Royal Agricultural Society, who referred the matter to their scientific adviser, who pronounced the insects to be cockroaches!
Mr. H. Warner Allen, the representative of the British Press with the French Army, writes as follows in the Morning Post:—
Of the smaller trench annoyances few are more worrying than the plague of rats. Shelters and trenches, no matter where they are made, whether in woods or open fields or on the mountainside, become immediately infested with the objectionable creatures. In one case within my own personal knowledge they drove a French officer out of a comfortable and commodious dug-out into a damp and melancholy shelter, which was to some extent protected from them by sheets of corrugated iron. The plague had attained considerable dimensions before a really organised attempt was made to deal with it, and there were many cases of rats actually biting men who were chasing them down the trenches.
Terriers have proved of considerable assistance. Trains full of dogs have been dispatched to the Front, and poison has been fairly effective. Lately, a reward has been offered for every dead rat brought in by men in the trenches, and regular battues have been organised. In a single fortnight one army corps alone has disposed of no fewer than 8000 rats. At a halfpenny a rat this has involved an expense of £16, and it was certainly money well spent. The sport of rat-catching on such very advantageous terms has proved very popular among the men, who now suggest that the standing reward offered for the more dangerous and more exciting form of sport involved in the capture of a German machine-gun should be raised to a higher figure.
Ferrets have been largely used in the British trenches, but their price is now very high, and the supply is very limited. The method which has had some success in combatting the rabbit-plague of Australia—killing all captured females and let all captured males loose—is certainly worth a trial. Rats will gnaw through concrete, but not if plenty of pieces of broken glass be mixed with the concrete. They will never cross a band of tar which has been kept liquid by mixing with grease. In the French trenches, special rat-runs are dug and these are provided with ‘live’ wires. On touching one of these the rat is electrocuted.
In the eighteenth century, among the officers of his ‘Britannic Majesty,’ was an official rat-catcher, whose special uniform was scarlet, embroidered in yellow worsted with figures of field-mice destroying wheat-sheaves. Inquiry at the Lord Chamberlain’s office has satisfied me that the officer still exists and still catches rats, but I fear the uniform has been abolished. However, a book has recently appeared dealing officially and exhaustively with all matters of this kind, and as soon as I can come by it, I will look the matter up. Should this dignified uniform have really disappeared, might not a humble petition be presented that it be revived? Surely, never more than at the present time should the honour and glory of the rat-catcher be exalted!
CHAPTER XIV
THE FIELD-MOUSE (Apodemus sylvaticus)
TO A FIELD-MOUSE