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TRAN SACT IONS. THE

ENGLISH

AS

DISSEMINATOR

BLACK OF

RAT

DISEASE.

BY DR. MARK R . TAYLOR, M . R . C . S . , etc.,

Southampton Regional Medical Officer of Health. THE Black Rat (Epimys Rattus, L.) is often spoken of as a relic of the past, with regrets for its disappearance. But the animal not only still survives in England : it is holding its own, in some places gaining predominance over its competitor, the Brown Rat (Epimys Norvegicus, Bork.), and all seaports can produce specimens. In fact it has never entirely disappeared from such favourable surroundings as our docks and warehouses, wherein its numbers are recruited by fresh arrivals on shipboard. Somewhere in the thirteenth Century an incursion of these rodents spread over Europe, as migrants from central Asia. In England there was no Rat at that time, so the new-comers rapidly increased and populated the land, for everything was in their favour : they were a race that lived with man and on man, and the man of that period furnished them with the most suitable lodgings. English folk in mediaeval times were habituated to such surroundings of filth and general uncleanliness that our imagination is stretched to realize how they did exist at all. T h e majority of the upper classes dwelt in wooden houses, with most primitive systems of sanitation ; the lower sheltered in hovels, mainly mud-walled, with no light, no Ventilation beyond a hole in the roof to liberate the smoke, a kennel or garbage-heap outside the door, and no sanitation whatever. Hence every house, whether °f rieh man or poor, became a Rat-run. If these animals acted as seavengers to some extent and so did their good deed a day, they were also the disseminators of disease : for Black Rats are intested by five different species of Fleas which can convey the virus of Plague. T h e cycle is thus : a Flea bites an infected heing, man or rat, so that the victim becomes infected and dies, i ne Fleas on him leave the corpse when it becomes cold, as is the custom of all Pulicidse, and find fresh victims to bite. 'ortunately the species of these Fleas, that has much the greatest power of conveying Plague, is by far the rarest; so that Plague


202

THE ENGLISH BLACK RAT.

becomes a real danger to the Community only when that particular kind of Flea increases out of proportion to the other four. As long as the ratio of this Flea to the others is under one per centum, all seems fairly well; but in epidemics of Plague the proportion may rise to twenty per centum or more.* It is easily understood that, with a huge population of Black Rats and their attendant Fleas throughout E ngland in the middle ages, Plague could never be far off. Actually, in one form or another, sporadic or epidemic, it existed here throughout several centuries : again and again the country was swept by contagion. T h e greatest and best kr.own of these was the Black Death that caused huge mortality. It is estimated that in certain districts nearly half the population perished : we can come at some idea of the numbers slain by the manor-court rolls, which show whole families to have been exstirpated ; and by the Ordination rolls, indicating enormous mortality among the priests, for as many as three inductions to a single parish were made during the one year, 1349.{ Entire villages were wiped off the m a p : the inhabitants died and there was none to bury them ; their houses feil down and formed their tombs. T h e parish church alone remained Standing, and in some East Anglian places still stands, now solitarily because the new village was built away from the infected area, as at Bildeston. So epidemic went on with fluctuating severity until the 1665 Great Plague in London, after which outbreaks in England became persistently rarer. Some folk say this diminution of infection was due to the advent of the Norway or Hanover Rat (E. Norvegicus), which invaded the country at about the end of the seventeenth Century. T h e Brown Rat is a far stronger and fiercer beast than the old English Black one, and gradually killed off its predecessor except in a few strongholds about our docks. Now we have some difficulty in discovering a Black Rat, for ceaseless war is waged on it by the medical officers of ports and a careful tally kept of the numbers slain ; but still, in some years, actually more Black are killed by port ratcatchers than Brown ones. Modern building * T h e Flea that conveys plague most freely is Pulex (Xenopsyllä) Cheopis, Rothsc. E M M . 1903, p. 85 ; cf. I.e. 1905, p. 139. T h e other two commonest Rat-fleas, X. astia, Roths., and X. Brasilensis, Bäk., bite m a n m u c h less readily in a tropical climate, though they may be just as activc in a temperate o n e . — M . R . T . JHistorically the Black Death of this year is known as Pestilentia Prima et Magna, a festo sanetse Petronilla; usque ad festum Sancti Michslis, extending f r o m 31 May to 29 September. T h a t there was searonable is shown bv Pestilentia Secunda lasting from 15 August 13t>i to 3 M a y following ; and Pestilentia Tertia f r o m 2 July to 29 September 1369. So great was the confusion of land tenure occasioned that these dates became eoochs, whence charters and other legal instruments wer dated ; hence their exaet incidence had to be ascertained by the Clarenceux K i n g of Arms, t e m p . Chas. i.—Ed.


BLACK RATS,

Epimys Rattus, Linn.


THE ENGLISH BLACK RAT.

203

methods seem to favour t h e f o r m e r ; concrete floors and proper drainage prevent ingress by Brown Rats, which are par excellence sewer rats. O u r subject is far the n i m b l e r and a better c l i m b e r ; he is asserted to invade warehouses via the telephone-wires, if no easier way be available. English sympathy with the u n d e r d o g may account for regrets at his passing; b u t , if his history be studied, we must agree that the only good Rat is a dead R a t — a n d even he is not really good, for he may be passing on his infected Fleas to us ! Those who weep for the Black Rat can truly u r g e that he is a much more engaging Iittle beast t h a n his cousin. H e is a rather smaller a n i m a l ; his large and naked ears lend h i m a plaintive appearance, and make his face resemble that of a large M o u s e rather than the cruel and crafty countenance of the Brown Rat. His tail, too, is darker, finer and longer ; and his disposition a good deal gentler. If any M e m b e r of our Society should wish to s t u d y him in the flesh, doubtless the port ratcatchers of Ipswich and Yarmouth can supply specimens ; for both o u r Rats are most prolific: five or six broods each year, with seven or eight in a litter, is about the average increase. So, if N a t u r e did not assist us in keeping down the vermin, not only should we be eaten out of house and home, b u t very soon crowded out as well. T h e Rat would seem one of those animals that man can happily destroy without unduly biasing t h e equilibrium of N a t u r e .

A SECOND FOSSIL BIRD.—The clavicle of a Bird was f o u n d by me in Pleistocene peat of the Forest Bed at Corton about 27 December 1932, and is now in the collection of M r . W . J. H e n n Collins a palseontologist in Guernsey, w h o witnessed its discovery. It quite certainly pertains to a Merganser (Mergus) and almost certainly to our Suffolk Red-breasted Merganser (M. serrator, Linn.).—E. A. ELLIS ; M a r c h , 1934. [Fossils of no more t h a n two kinds of Birds have been recorded f r o m our County hitherto ; of these one must be relinquished to Norfolk, for n o more is k n o w n of it than that, " f r o m t h e Chillesford Crag beds of Aldeby, Sir William Flower identified remains of the Guillemot, Uria tnole " (Vict. Hist. 33 : omitted by Ticehurst, 432). T h u s our sole instance is that of " fossil bones of a bird of this [Albatross ] lamily, unearthed in the R e d Crag of SufTolk dating f r o m Pleiocene [sie] times. T h e bird, which belonged to no species known at he present day, was n a m e d Diomedea anglica by Lyddeker " in Vf.1- F o s s - Birds in Brit. M u s e u m 1891, p. 189 (Ticehurst 1932, T*™)- M o r e exactly these were the two foot-bones in a sandy bed overlying the Red Crag at Foxhall, now in Ipswich M u s e u m ; and part of an ulna f r o m Coralline Crag at O r f o r d , in M u s e u m °r "ractical Geology (Lyddeker in Vict. Hist. 1911, 42).—Ed.]

The English Black Rat as Disseminator of Disease  
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