Corporation of London. PUBLIC HEALTH DEPARTMENT. SANITARY COMMITTEE. REPORT, MEDICAL OFFICER OF HEALTH, ON RAT REPRESSION IN THE CITY, 1920. Ordered to be printed 15th April. 1920. COOPER, Mayor. A Common Council holden in the Chamber of the Guildhall of the City of London, on Thursday, the 15th day of April, 1920, THE Sanitary Committee did this day deliver into this Court a Report in writing on the Reference of the 22nd January, 1920, relative to the Rats and Mice (Destruction) Act, 1919, and :— Submitting a Report by the Medical Officer of Health (Dr. W, J. Howarth, C.B.E.), on Rat Repression in the City; and recommending that the same be printed and circulated amongst the Members of the Court, that copies thereof be forwarded to the Ministry of Health, the Ministry of Agriculture and Fisheries, the London County Council, the Metropolitan Borough Councils and others. Agreed to, and Ordered accordingly. BELL. To the Right Honourable the Lord Mayor, Aldermen and Commons of the City of London, in Common Council assembled. REPORT—SANITARY COMMITTEE. IT will be within the recollection of your Honourable Court that on the 22nd January, 1920, you referred to us the Rats and Mice (Destruction) Act, 1919, to take such steps in the matter as may be necessary, reporting to you thereon from time to time. We have had a Report from your Medical Officer of Health on Rat Repression in the City, which we submit herewith, and beg to recommend that the same be printed and circulated amongst the Members of the Court, that copies thereof be forwarded to the Ministry of Health, the Ministry of Agriculture and Fisheries, the London County Council, the Metropoliian Borough Councils and others. All which we submit to the judgment of your Honourable Court. Dated this thirtieth day of March, 1920. Signed on behalf of the Committee, W. H. SAVERY, Chairman. Corporation of London. Public Health Department, Guildhall, E.C. 2, 2Ath February, 1920. The Worshipful the Chairman and Members of the Sanitary Committee. RAT REPRESSION IN THE CITY. Gentlemen, I have the honour to report as follows on the subject of rat repression in the City :— (1) For the past eighteen months the rat problem has been the subject of special investigation work in the City. This work has been in charge of Mr. Mayne, who was appointed Temporary Inspector for this particular purpose. Your Worshipful Committee have been provided with several pamphlets which have been published on this subject, and the present Report, therefore, need not discuss, except in the briefest possible manner, such points as natural history, the damage done by rats and the dangers of rats to the community. In this latter connection I may recall the work of Professor A. G. R. Foulerton on "The Protozoal Parasites of the Rat," which was carried out on your behalf. The details of his research were printed and circulated among interested persons and societies. (2) NATURAL HISTORY AND HABITS OF RATS.—The two types of rats found in the City are the black rat (rattus rattus), known also as the house rat or ship rat ; and the brown rat (rattus vorveyicus). The City seems to house either rat without special selection of district. Each type has been found in the Central area and also in the districts nearer the docks. The two rats, however, differ considerably in their mode of life and existence, and it is important to know the habits of the two varieties in making inspections of the districts. The black rat is seldom found to enter premises by drains or basements and does not as a rule burrow. It generally establishes itself in walls, between floors and ceilings and in roofs. It is an expert climber and not only gets to the roofs of houses and window ledges by means of stack pipes attached to the walls, but travels long distances on overhead electric and telephone wires. These rats may be seen on a bright night in the City crossing overhead from street to street by these means. They enter premises by way of chimneys, windows, roof ventilators and any other openings, and only a very thorough system of rat-proofing will protect a building from their invasion. The brown rat is always to be found in sewers and drains, and generally enters a building through a defective drain or an unprotected area window. It is also a good climber, but is not a "Blondin" like the black rat. It frequently burrows from a defective sewer or sewer connection under the footpaths and works its way along until it finds a weak spot in a basement wall or the brickwork of a coal-shoot where it gnaws through and obtains entrance. It frequently breeds under the pavements, and many nests of young rats have been found when flags have been lifted on the City side walks. When recently examining a rat-infested house in Aldgate, it was found that <> o ' brown rats had burrowed to such an extent in the basement that nearly half a cartload of earth was heaped on the floor from their burrow. These facts emphasise the necessity for keeping the sewers and connections in sound conditions and the basement walls and floors thoroughly rat-proof. At night, numbers of rats are always to be seen running about the streets. Some of these gain entrance to buildings through unprotected area gratings, defective basement lights and windows, and frequently through doors which have been left open. In some cases where the entrance pavement has been laid with a slope in order to avoid the necessity of a step, the doors, when closed, have a wide space underneath which rats readily avail themselves of as an easy means of entrance into an otherwise fairly rat-proof building. 2 (3) DAMAGE DONE BY RATS.—The damage done by rats in the City must be enormous, but it cannot be estimated without systematic enquiries and thorough investigation. Great damage has been done to property by rats gnawing through doors, floors, ceilings, walls and lead soil and water pipes. In places where food is stored in quantities, as in wharves and warehouses, much food has been destroyed by these animals, as also in workshops and similar premises where meals are provided for the staff. Such items as boots, books, clothing, furs and articles of furniture and valuable textile goods are also damaged and rendered unsaleable. At a butcher's shop near Holborn Circus, not only were the floors, walls, ceilings, and chimneys riddled with rat holes, and the lead soil pipe eaten through, but when the business closed down and the supply of food ceased, the rats, before migrating to other premises, actually gnawed the wooden handles off the meat saws left behind. The apparently wanton damage done by rats to such articles as hard-wood furniture, lead pipes, bricks, &c., is possibly done with the object of keeping their continually growing teeth at a proper length. Specimens of damaged lead pipes, boots, furs and clothmg from City premises were sent to the Curator of the Zoological Gardens and formed part of " Rat Exhibition" recently held there. (4) RECENT LEGISLATION. The Rats and Mice (Destruction) Act, 1919, which became operative on the 1st January this year, involves the Corporation, the citizens and the occupiers of premises within the City in additional responsibilities in connection with the suppression of rats. The first section of the Act reads as follows :— "(1) Any person who shall 'fail to take such steps as may from time to time be " necessary and reasonably practicable for the destruction of rats and mice on or in any land " of which he is the occupier for preventing such land from becoming infested with rats or " mice shall be liable lo penalties." In the City, the Common Council are the Authority required to execute and enforce this Act. The London County Council are responsible for rat suppression in any sewers in the City which may be vested in the County Council. The Corporation are also required to observe the requirements of this Act in respect of land of which they may be the occupier, and in case of failure the Ministry of Agriculture and Fisheries may undertake the work and recover the expense incurred. The Corporation may, within its area, give instructions by public notice as to the most effective methods that can be adopted both individually and collectively with a view to the destruction of rats and mice.. Presumably the free distribution of a pamphlet of instructions would be regarded as public notice. The Corporation can also call upon the occupier of any vacant land to take steps to destroy rats on the land or to prevent the land from becoming infested with rats and mice. (5) POSITION IN THE CITY.—Although probably not every premises in the City harbours rats, I do not consider that there is any part of the City area which can be reasonably deemed to be free from rat infestation. Such buildings as are generally free are exposed to intermittent infestation as a consequence of rats gaining access in the ways already described. Two problems present themselves—(1) the riddance of buildings of rats and (2) the riddance of the district as a whole. (6) INFESTATION OF PREMISES.—The first of these problems cannot be regarded as insuperable, given an unlimited purse. Investigations show that under present conditions of outside infestation and provided a building is structurally such as will furnish the rats which gain access with means for nesting and, therefore, for propagation, and that it also contains the necessary food supply, such a building will continue to be infested to the limit of the means of subsistence unless suitable measures are adopted. The problem as regards buildings, therefore, resolves itself into the removal of internal structural defects, so as to ensure that walls, rooms, floors and ceilings shall furnish no nesting places and the provision that all food supplies shall be stored in rat-proof receptacles. An efficiently rat-proofed building should not only provide no means for breeding or shelter, but the walls should be resistant to the burrowing or gnawing activities of rats, and premises should be provided with defences against 3 ingress of rats from the streets and upper floor levels. In the City, unfortunately, it is only the more modern buildings which are so satisfactorily constructed, the older buildings present all degrees of deviation from this ideal ; in fact some would appear to have been constructed with the object of not only conducting business, but of furnishing rats with a maximum of convenience. (7) RAT-PROOFING.—The principles to be observed in rat-proofing existing buildings are the following :— (i.) A good cement floor should be laid down, particularly in the basement. (ii.) All holes in basement walls should be filled up with brick or glass and cement. Loosely filled spaces should similarly be treated, particularly where drains run in close proximity to the floor. (iii.) In old buildings where lath and plaster ceilings are attached to the joists or rafters, the lath and plaster should be removed leaving the joists exposed so that no tats can harbour there. In new buildings floors and ceilings are usually of solid construction. (iv.) Doors should be made to fit satisfactorily and, if necessary, the foot should be fitted with sheet iron. (v.) Openings into basements such as area windows, or the ventilating windows of W.C's near the ground level, should be fitted with small mesh galvanised iron wire netting—1/2-inch mesh is a suitable size. (vi.) Disused drains which formerly opened into the basement or other parts of the premises should be removed and the opening at the sewer end satisfactorily made tight with cement. (vii.) A sound sewer is also necessary as a security against infestation of buildings since the rats leaving the sewer will burrow along the side of drains and reach the basement if any weak point can be discovered. (viii.) Walls should be impervious to attacks by rats from outside. (ix.) It seems almost necessary, in view of the possibility of the black rat gaining access to upper floors, and particularly where these are used as restaurant kitchens, to guard the posts and carriers of telegraph wires, and in other ways to construct suitable roof defences. (8) FOOD SUPPLY.—In addition to rat-proofing, every precaution should be made to ensure that food is kept in rat-proof receptacles or chambers, and in places where meals are consumed on premises even the crumbs should be removed each evening. In addition, refuse which is stored in kitchens should be contained in metal tins and the covers should be invariably tight-fitting and kept in position. Since writing this Report I have noted the following observations by Dr. Louis Sambon, delivered in the course of a lecture on Tropical and Sub-tropical Diseases before the Royal Colonial Institute, and reported in the "Lancet" of February 28th, 1920 "The slaughter only renders conditions more favourable for the multiplication of the "survivors. The increased mortality is met by increased birth-rate, and, as everyone knows, "the rat's breeding powers are incredible. Five to 10 litters in a year, 6 to 20 young in a "litter, and the young able to breed in less than three months ! Besides, what would be the "use of destroying rats unless we made adequate provision to prevent more rats from "landing ? Every ship brings rats, especially grain ships, a thousand and even 1,700 rat "carcases have been counted after fumigation of a single ship, and thousands of ships reach "our ports. What we can and should do is to render our wharves, quays, markets, store"houses, and other public buildings rat-proof. The rat must be entirely excluded from "occupied buildings. He must be de-domesticated, if I may use the expression, he must be "built out of existence—as Surgeon-General Blue tersely puts it. Attracted by food and "cover, he has overcome every fear of man and imposed himself upon us as an effronted and "dangerous commensal. The proper storage of food, the immediate removal and burning "of all food wastes, garbage, and rubbish, the destruction of places in which he may find "harbourage, and the contrivance of architectural modifications apt to cut off his approach, "the liberal use of concrete, wire netting, and sheet metal will certainly discourage him." 4 (9) THE RIDDANCE OF PREMISES OF RATS.—It is obvious from what has already been stated that any immediate attempt to bring all premises in the City up to an ideal standard would be impossible. As it is, occupiers will be involved in considerable expense, and I must confess that I find it, difficult to set out a uniform course of procedure. Each case will require to be dealt with on its merits, and it will be necessary for the district to be divided into areas and each to be under the charge of an inspector, in order that satisfactory progress may result. In addition to improvements in the matter of requiring buildings to be rat-proof, other means are available, many of which are worthy of application. The particular circumstances of each premises will determine the most suitable method to employ. (10) TRAPPIN.G.—Various forms of traps are on the market and are more or less useful. The best of these is the simple " break-back" trap, in which a spring is released when the bait is gnawed and the rat killed by violence. Wire rat-traps seem of very little use. Another useful device is the barrel trap. The structure of this trap is as follows : a barrel is taken and into it are run a few inches of water. A brick standing on its end is then placed so that some three or four inches of it stand above the water. The barrel is covered with a drum-head of brown paper. For several nights bait is placed on the middle of this paper. On this the rats feed. When confidence has been gained, the central portion of the paper is cut through in the form of a cross, leaving only a very feeble connection in the centre which will break with the weight of the rat. On this the bait is again placed. The rat proceeds to the bait, breaks the feeble connection and drops into the barrel. He then mounts the bricks, and his squeals attract other rats in the neighbourhood; some of these rush on to the brown paper and fall into the trap. Reports have reached me of as many as 40 rats being caught in one barrel in one night in the City. The "Figure of Four" trap is a contrivance whereby a rectangular piece of wood or metal, bearing a weight (a large box will meet the case), is supported on the angle formed by two thin pieces of wood only one of which is supported on the ground. This vertical angle is locked by a third piece placed horizontally, forming the figure 4. The horizontal strip is notched and slides down the angle of the wood, finally forming a lock. On this horizontal piece is placed the bait, on the rat gnawing which the lock is loosened, with the result that the weight above falls and crushes the rat. This trap is useful for catching a single rat, and sometimes it receives great credit for succeeding in catching the wary rat of large size, which is generally assumed to defy rat-catchers, poisons, traps and other devices. FIGURE OF 4 TRAP. (11) LARGE TRAPS.—Perhaps the want of continuous success in trapping rats is due to the smallness of the size of the trap used and the shyness of the rat to the contrivance. The clicking noise which most traps make must also prove an objection. For this reason it seems desirable that traps for use inside buildings should be of the largest size convenient, and be made to resemble as little as possible a special contrivance which is foreign to the room. It would appear, therefore, that if the room 5 itself could be made into a trap, success would be more certain. This, however, can only be done provided the entries to the room are not too numerous and the furniture and room contents are not too bulky to prevent their being easily moved. Given these conditions there seems no great difficulty in arranging for all openings by which rats gain entrance to be fitted with spring covers releasable at will. (12) There are certain places where either this arrangement or the Stockade trap might be useful. This latter trap consists of a simple four-sided compartment of suitable size with a large sliding door dropping on to the floor and set in one of the sides. This door is releasable at will by means of a string or wire attachment carried outside the room. For a few nights the trap is left in the room with the door fixed open, and rats are allowed to enter and leave at will. They are encouraged to enter by suitable baiting, and when the trap is considered to contain the maximum number of rats the door is released. The sides of the trap should be constructed so that the contained rats cannot climb over it. A small tube may be placed in one corner of the trap, the inside part being left open and the outside covered with a bag. The captured rats may be driven into the bag through the tube and thus removed alive. (13) POISONS—BARIUM CARBONATE.—Quite a number of useful poisons have been suggested as suitable for use, and among these Barium Carbonate has been shown to be one of the most reliable. It is cheap and tasteless, and on the latter account can readily be made into a suitable bait. The action of this poison is corrosive, and as a consequence rats poisoned with it leave their holes in search of drink. (14) SQUILL, which is obtained from the plant Scilla Maritima, and used either in the form of a powder or in solution, has proved to be effective. It seems to be extremely toxic for rats, a lethal dose being stated to be only half a grain; it is, moreover, regarded as comparatively harmless to domestic animals. (15) STRYCHNINE, ARSENIC AND PHOSPHORUS—have also been advocated as suitable poisons. Strychnine is too deadly to recommend for general use. Arsenic does not appear to be acceptable in bait to rats, but phosphorous, although readily recognisable, has been shown to be reasonably attractive. The above poisons, either alone, in combination with each other, or in combination with other poisons, form the basis of most proprietary rat-poisoning pastes which are on the market. (16) Suitable formula? and suggested methods for using the above poisons are set out in the Appendix. 6 (17) Poisons are most suitable for use in the open, particularly when there is little risk of domestic animals picking up the bait, and in the case of open spare ground, such as that which is left after the demolition of a building, poisons judiciously laid down undoubtedly represent the best means of attack. Inside premises the main objection to poisoning is that where the rat has made a room its natural home, the rat frequently dies on the premises. In such cases, therefore, repeated poisoning means a continual increase of dead rats lying in inaccessible places. To meet this difficulty I note that it is suggested in the Memorandum on Destruction of Rats and Mice issued by the Ministry of Agriculture—"That there is always a possibility of a rat dying under floorings or behind wainscoting, either through poison or otherwise. If a rat from a drain takes poison and cannot regain its habitation, the carcase will most probably become putrid. If such a rat dies near a fireplace or a hot-water pipe, the stench will be intensified. Chloride of zinc is a good deodoriser in such cases, and combines with and neutralises the offensive chemical products of putrefaction. If necessary a hole should be bored with a bit and brace in the vicinity of the supposed origin of the odour if possible. Some perfume or pine wood oil can be added to the zinc chloride, which should be applied through a hole, A cork will close the orifice and can be withdrawn from time to time to ascertain whether the nuisance has abated." It is not always easy to locate with even approximate precision the exact place of origin of a smell, and deodorisation does not appear to be the remedy. Particularly is this the case if, as suggested, repeated invasions, as must result in many premises in the City, are dealt with by poisoning. For these reasons, I prefer to suggest that rats should be exterminated inside business premises by means which ensure the bodies being readily recovered. (18) VIRUSES.—Viruses have been on the market for a long time, and by some have been assumed to be of special value. Experience hardly supports the suggestion, and in addition there are certain objections which may justifiably be advanced against the use of viruses, particularly in places where food is prepared. These viruses have been investigated in several laboratories and, as a rule, they have been found to be cultures of Gaertner's bacillus or allied species. With the object of ascertaining what the present composition of these viruses might be, I sent samples of three purchased in the open market to Professor Andrewes, City Bacteriologist, who reports as follows :— "The three viruses sent for examination were specimens of :— "(a) A living Agar culture. "(b) A tin of material resembling bread paste. "(c) A bottle of living culture in a fluid medium. "(a) Virus proved in every respect identical with Gaertner's B. Enteritidis, giving "the same fermentation reactions and being agglutinated to full titre by a Gaertner serum. "(b) Virus. This material yielded on culture a preponderance of colonies resembling "those of Gaertner's bacillus, together with a number of contaminations. The former "differed from classical Gaertner's bacillus in being non-motile, and were only very weakly "agglutinated by a Gaertner serum, and not at all by a Aertrycke serum, or by two "paratyphoid sera (A and B). They gave weak agglutination by a typhoid serum. The "nature of the organism was thus doubtful. I therefore fed two mice on the virus. These "were at first unaffected, but one died in seven days, the other in ten days. The appearances "were those of Gaertner infection, and the bacillus was readily recovered from the heart's "blood and enlarged spleen in each case. The bacillus, though now motile was, however, "still only weakly agglutinated by Gaertner serum and not at all by Aertrycke serum. "I cannot, therefore, affirm that this virus is Gaertner's bacillus, though 1 conjecture "that it may be this organism modified by long culture. Other observers have found this "material formerly sent out as (6) virus to be typical Gaertner. ''In any case the tin of virus received by me was of a low order of virulence. "(c) Virus proved also to be B. Enteritidis (Gaertner). Subcultures were "spontaneously agglutinable, so that at first the agglutination test failed, but on testing the "original fluid culture sent out, it proved well adapted for the test and gave specific "agglutination with a Gaertner serum. The fermentation reactions were also identical "with those of Gaertner's bacillus. 7 "Both these strains were also tested with sera of B. Suipestifer (Aertrycke bacillus), "but they yielded negative results. "Remarks.—These viruses and several others have been the subject of careful study "by Bainbridge (Journal of Pathology and Bacteriology, vol. xiii., p. 443 (1909) ), who "found that all but one of the rat viruses investigated were Gaertner's bacillus, the exception "being a B. Suipestifer (Aertrycke). "More than one outbreak of food poisoning in man has been traced to the employment "of these viruses for killing rats and mice. I would specially recall an outbreak at an "establishment in Holborn many years ago, investigated by Dr. Klein, which seemed "due to the (b) virus. "The pathogenic powers of Gaertner's bacillus for man are so well established that "I regard the use of viruses of this type, for killing rats, as potentially dangerous to "man, especially in crowded centres of population, though in the country their use may "be more free from objection." (19) From this Report it will be noted that Professor Andrewes directs attention to the possibility of food poisoning resulting, and I might remind your Worshipful Committee that my predecessor in 1908 reported on an outbreak of illness occurring at a large business establishment in the City where a considerable number of persons of both sexes were employed. I rather think this is the outbreak referred to by Professor Andrewes in his Report. At this establishment, between the 18th and 22nd July twelve men became seriously ill, the symptoms being severe headache, vomiting, diarrhœa, cramp in the abdomen, and giddiness with severe collapse in many cases. These symptoms were accompanied by fever and high temperature, and the patients looked and were extremely ill. The severe symptoms lasted about 48 hours, but each case recovered and was practically convalescent at the end of the week. Investigations showed that all the patients had dined in one room, and that no person who had dined in each of the four other dining rooms which the firm provided were attacked. An offensive smell was noted in the particular dining room used by the patients, and on removal of some of the floor boards the dead bodies, more or less decomposed, of a large number of mice were found. It was then ascertained that a much-advertised virus for the destruction of rodents had been used in this room and in the pantry adjoining. The virus had been laid about on pieces of bread, and it is easy to conceive that mice eating the poison might carry about the contagion contained in the virus on their feet to the floors, shelves, chairs, tables and plates, and thus it might subsequently infect human beings dining in this room. The virus used was at that time stated in the advertisement to cause a fatal disease amongst rodents, but to be harmless to domestic animals and human beings. Dr. Klein investigated the outbreak and made experiments which he considered proved conclusively the identity of the microbe recovered from the patients' stools and that contained in the virus. As a consequence of this outbreak two other viruses were examined, and he came to the conclusion that all were culturally and morphologically closely related and belonged to the group of bacteria included in the group of "paratyphoid." In considering this outbreak, Savage (Food Poisoning and Food Infection) writes as follows:— "The cultural tests used by Klein were insufficient to distinguish microbe 'S' (the "bacillus isolated from the stools of the infected patients) from the para-Gaertner bacilli, "and it is not clear whether this organism was a para-Gaertner bacillus or a true Gaertner "organism,-euch as B. Suipestifer. "The outbreak is of great interest, but the available evidence both on bacteriological "and epidemiological grounds is insufficient to prove that it was caused by the rat virus." (20) Apart from the use of proprietary preparations containing organisms of the Gaertner Group, it has been proved that Gaertner bacilli may be met with in the intestinal contents of rats and mice. So recently as 1910 Heuser* isolated Gaertner bacilli in five instances from the intestinal contents of 100 mice examined. The mice examined showed no symptoms of disease. He also found B. Enteritidis, but not B. Suipestifer, as a result of the examination of about 60 white rats. * Quoted by Savage. 8 Two other observers in 1911, Zwick and Weichel,* found Gaertner group bacilli present in 28 out of 177 mice examined. Other observers have failed. Savage and Reid* in 1913 failed to isolate Gaertner group bacilli from the intestinal contents of 41 rats, but isolated five strains of B. Enteritidis from the spleens (in two cases also from the liver) of different rats. Commenting on these observations, Savage writes :— "In two instances Danysz's virus (B. Enteritidis) had been distributed quite recently, "while two and a half years' previously the refuse tips and slaughter-houses from which "these rats were obtained had been extensively dosed with this virus. It is highly probable "that the bacilli isolated were derived (except in the two cases of recent infection) from an "old infection with this virus, a conclusion supported by the failure to find this organism in ''the intestinal contents, and by the fact that the serum from a number of these rats "agglutinated B. Enteritidis in high dilution." A later investigation by Savage (1918) confirms this hypothesis, since 48 rats obtained from a different source showed no Gaertner group bacilli or Gaertner group agglutinins. As regards domestic animals, the present view appears to be held that Gaertner bacilli are not normal inhabitants of the intestines of domestic animals, though the relation of animals already infected with types of B. Enteritidis to food poisoning is one of importance. Bainbridge, in 1912, suggested the possibility of infection of the alimentary canal of cattle and other domestic animals through contamination of their food or bedding by rats. Two German observers, Langer and Thomann, in 1914, attributed an outbreak of food poisoning, in which there were 11 cases with two deaths, to the consumption of a meat pasty, from the flour of which it was prepared they isolated the organism which they considered as responsible for the outbreak. Investigation seemed to indicate that infection of the flour had resulted from contamination with one of these bacterial preparations. These various observations are of considerable importance, since they tend to show that Gaertner bacilli are not natural inhabitants of intestines of either rats or mice, but that both these animals may be infected by these organisms, and the result may be death or recovery or the animals may survive as carriers. The possibility, therefore, of chronic carriers resulting as a consequence of animals partaking of baits containing these viruses is one of importance, and additional investigation work ought to be undertaken with a view to ascertaining whether the risks thus resulting are real, and, if so, whether in towns where there is a possibility of carrier animals gaining access to food and thus contaminating it, the use of viruses should not be prohibited. (21) VARNISH.—In the course of enquiries Mr. Mayne discovered in certain premises in the Aldgate end of the City that a rat-infested premises was periodically dealt with by setting down pieces of cardboard covered with varnish. The circumstances seemed to justify further investigation, and subsequent work with varnish definitely proved that for certain purposes no better trap exists. It has been found to be exceedingly fatal when used in premises where only a few rats have gained access. In two or three nights such places have practically invariably been cleared. In heavily infested places such as occur near the river, six or eight cards laid down night after night for a continuous period result in a considerable number of rats being caught. Typical examples of results obtained are set out in the following table. * Quoted by Savage. 9 Information showing the results of continuous Varnish Trapping in certain premises in the City. Premiseslin Joiners' Hall Court. Premises in Old Bailey. Premises in Great Tower Street. Offices in Queen Victoria Street. Date. No. of Cards set. No. of Rats caught. Date. No. of Cards set. No. of Rats caught. Date. No. of Cards set. No. of Rats caught. Date. No. of Cards set. No. of Rats caught. 1919. 1920. 1919. 1920. Nov. 12th 6 8 Jan. 15th 6 4 Dec. 11th 12 9 Jan. 3rd 4 1 13th 6 12 16th 2 2 12th 11 2 5th 4 10 14th 6 4 19th 12 20 13th 11 3 6th 4 0 15th 6 1 20th 12 5 15th 11 6 7 th 6 1 17th 5 3 21st 12 4 16th 11 8 8th 6 2 18 th 5 7 22nd 12 9 17 th 4 4 9 th 6 2 19th 6 2 23rd 12 4 18th 11 5 14th 9 0 21st 6 2 24th 12 4 20th 8 1 15th 9 0 24th 11 3 24th 26th 12 8 22 ad 4 4 25th 11 3 27th 12 1 23rd 4 2 26th 6 4 28th 12 3 24th 4 2 27 th 6 5 30th Feb. 2nd 12 10 29th 4 0 28th 6 4 3rd 12 5 30th 10 0 29th 6 3 31st 6 1 Dec. 1st 6 1 2nd 8 5 1920, 10th 6 9 Jan. 1st 2 0 12th 6 8 6th 4 0 24th 6 10 29th 6 1 30th 6 1 31st 5 1 Totals 97 79 47 16 (22) So far as the City is concerned this trap, pending the discovery of something better, has established for itself the right of a permanent place in rat repression. There are one or two precautions to be observed. It has been noticed that if rats approach the trap—which simply consists of lithographer's varnish of a certain consistency spread on cardboard—along a track which is greasy, they are able to escape, as the varnish does not seem to hold sufficiently. Similarly, excessive moisture, or sand which adheres to the feet, is a disadvantage. In rooms which are exceedingly hot as, for instance, those in which there is a boiler in which steam is kept up all night, or in which a baker's oven is maintained at a high temperature, a varnish of greater strength requires to be used instead of the one ordinarily recommended. As many as five rats have been caught in one night on one card about 18 inches by 12 inches superficial area, and the varnish seems to have sufficient holding power to hold rats of the largest size. The rats are practically always found dead in the morning. It was difficult at first to suggest the reason of death, but I think it is probable that most die of suffocation as a consequence of the mouth and nostrils being closed with the varnish when the rats attempt to free their limbs. Death in these circumstances must be distinctly less painful than that which results either from the fumigation of a room or from the ingestion of any of the irritant poisons. (23) RAT-CATCHERS.—Rat-catchers often serve a useful purpose in the programme of repression. Their method of working needs no extended reference, but there are certain points in connection with the business which require notice. I consider that if an organised attempt at rat repression is undertaken by a community it is desirable that the rat-catchers should work in conjunction with local officers appointed for that purpose. It is essential that the local officer should know the premises which require the services of a rat-catcher. They should know what success has met his efforts, .and the Authorities should be made acquainted with the means adopted for the disposal of the captured rodents. Some form of control as well as a measure of co operation is necessary, and registration of rat-catchers with the Local Authority seems the best 10 way of proceeding. I suggest, therefore, that a conference between your officers and those rat-catchers who are known to work in the City should be held with a view to establishing some form of voluntary registration and for setting out the rules with which a person should be required to comply to entitle him to registration, and further, if a suitable scheme can be devised, it is desirable that occupiers of premises in the City should be notified of the fact and requested only to engage a rat-catcher who is on the City's registered list. (24) RAT REPRESSION AS APPLIED TO THE WHOLE AREA.—The problem of rat repression as applied to the whole community presents many difficulties and is one of no mean magnitude. Certain general principles must be observed, even if these are wrong and require future alteration, if a satisfactory working policy is to be laid down. At the present time two chief conclusions seems to be justified :— i. Rats apparently multiply to the limit of the means of available subsistence. Under favourable conditions litters are large since reproduction is carried out under a maximum of satisfactory circumstances. When food supply is less than is necessary to maintain in a satisfactory condition the rats which exist in an area, there probably results an automatic control owing to increased mortality and reduced fecundity. ii. Intermittent attempts at rat diminution almost certainly result in constant maintenance of maximum rat prevalence. The reduction which takes place as a consequence of sporadic efforts results in additional advantages being the legacy of those that remain, and a subsequent increase follows until the normal level is regained. (25) As already stated, premises can be made rat-proof and the available food supply decreased to a minimum. Within such places the rat population residing therein can be wiped out by the exercise of effort, but outside, considerably less can be done in either of these respects, and notwithstanding the best efforts, some harbourage and some food for rats will remain. So long as endeavours are active and continuous a permanent reduction in numbers will take place. This will proceed until a stage is reached when further reductions will only be achieved by efforts greater than those already put forth. (26) It would appear to follow, therefore, that with our present, knowledge we seem to be under the necessity of constantly fighting the scourge. If we relax our endeavours, the rat population, which has by previous efforts been reduced to a point below that which harbourage and food supply could maintain, will soon be restored to what is the normal level in the circumstances. Even if the Corporation, by improvements in sewers and by controlling food supplies, and private occupiers by improving their buildings and safeguarding such food as may be stored on the premises, constantly maintain their best endeavours, the question of offering some inducement to encourage persons, otherwise not interested, to make war on rats appears worthy of consideration. The only opening in this direction appears to be to pay for rats caught and killed, on adequate proof of slaughter, such as the production of the carcase or portion of the carcase, being forthcoming. It is doubtful whether a payment of 3d. per rat would prove any attraction. I believe that in Liverpool as much as 6d. is paid. The action of the Royal Society for the Prevention of Cruelty to Animals has probably done much to put an end to this kind of* personal endeavour without public payment. As a result of the Society's activities rat-baiting has ceased, and it was for this purpose that special efforts were once made to catch rats alive. It is not for me to consider the ethical aspect of the question, but I may be permitted to state that no 11 doubt exists in my mind that the slaughter of rats by terriers is as humane a method of destruction as that of poisoning by strychnine, arsenic, barium carbonate or sulphur dioxide. (27) A study of the excellent return of Zuschlag respecting rat repressive measures in Copenhagen and Frederiksberg in Denmark supports the view that although the normal rat population may be easily reduced, considerably increased efforts are necessary to reduce the numbers below a certain level, and this level probably is sufficiently serious to allow the animals rapidly to return to their maximum if laxity is allowed. The following table shows the number of rats caught in Copenhagen in each quarter of the year from 1907, in which year organised efforts were first put into practice. It will be seen that in the first year and in the first quarter of the second year, which was the July quarter, more rats were caught than in any subsequent year or quarter. The reduction after the first two years is not very pronounced. No figures are available to show how long it would take, if the rats at this reduced level were left alone, before they resumed their normal state of excessive prevalence. During the period July 1st, 1907, to June 30th, 1909, eight ore were paid for each rat killed. From 1909 to 1919 the payment was increased to ten ore, and consideration is being given to a still further increase. Table showing the number of rats caught in Copenhagen in the years 1907-08 to 1918-19, the totals being divided into quarterly periods :— Quarterly Periods. July, August and Sept. Oct., Nov. and Dec. Jan., Feb. and March. April, May, and June. Total for the Ytar. 1907-8 33,316 50,516 56,597 72,639 213,068 1908-9 80,294 26,828 17,962 29,748 154,832 1909-10 36,459 30,654 22,313 39,094 128,520 1910-11 36,554 31,502 24,140 34,915 127,111 1911-12 35,265 30,433 19,928 36,358 121,984 1912-13 31,849 28,445 21,348 35,669 117,311 1913-14 33,480 28,915 20,922 37,952 121,269 1914-15 38,004 32,834 21,539 31,867 124,064 1915-16 31,750 23,657 15,279 26,218 96,904 1916-17 25,347 20,023 16,134 22,901 84.405 1917-18 26,106 24,117 15,826 23,631 89,680 1918-19 21,452 23,242 17,618 21,910 84,222 I shall be interested to note the number of rat3 actually caught in Copenhagen when food supplies are again in a normal state. The notable decrease in the years 1915-1919 compared with 1911-1914 might be due to food supplies being diminished in consequence of the war, or to diminished activity—I have no information, however, on these points. (28) The work that has been done above, and which would correspond to energies in the City, is undoubtedly beneficial, but the rat problem still remains. Work and effort on the lines already indicated must be continued, but it is clear J that we should not rest satisfied with these measures. Research should be instituted, and as in other preventive branches, the results of research would probably prove a much better investment than acceptance of the present position, which is expensive and leads to no finality. It is difficult to lay down lines on which research could be carried out, but as indicative of what is meant, it is perhaps permissible to point out three directions in which it has been suggested that the problem could be approached with this broader conception in view. (29) (i,) It has been thought possible to introduce amongst the rat population some specific infectious disease which might prove fatal amongst the rats and yet be practically harmless to domestic animals or human beings. 12 At present I know of no infection which would answer these requirements. As already stated, the various viruses which have been used are known to introduce more or less fatal epidemics among rats, but the disease is not fatal to all, and some even acquire immunity and act as carriers with possible danger to public health, since the organisms used are certainly not harmless to human beings. Plague is notoriously fatal to rats, so much so that in plague-infested areas rats desert the district and so introduce the disease to a previously non-infected area. Plague is, of course, a fatal disease to which human beings are liable, and therefore cannot be used. I do not consider that possibilities in the above direction have been exhausted. (30) (ii.) An attempt has been made to reduce the number of rats by the introduction into a district of antagonistic species not normally indigenous to that area. The introduction to new areas of animals which have successfully acclimatised themselves to their new surroundings has not invariably been devoid of objection, e.g., rabbits in Australia, in which instance the introduced animal has constituted itself practically a plague. The mongoose was also introduced into certain parts of the West Indies to diminish the rat. It certainly effected its purpose, but I understand that this animal is now almost as objectionable as the rat, for the rat has acquired arboreal habits, and by limiting the supply available for the mongoose, the latter has turned to the chicken runs. 1 have also been informed that the mongoose causes considerable damage to the sugar canes. In this country the weasel, stoat and owl, and perhaps the hawk, are the known enemies of rats, but none of these animals or birds could be used in buildings. Some use might be made in City warehouses of the mongoose, and I attach a description by Mr. Jennison on how the mogoose should be tended. (31) (iii.) The introduction of some factor which will interfere materially with rat propagation, as, for example, that which would result from a disturbance of the numerical sex relationship has been advocated; this latter under the designation of the Rodier System. This method is advocated by Rodier for use against rabbits, and he claims with success. As regards the application in the case of rats, the only experience in this country I am acquainted with is that gained by Mr. Jennison at the Zoological Gardens, Manchester. I believe that it is possible for animals in the wild state to change from the monogamous to polygamous state, but not the reverse. Take for instance the bird of paradise, which was formerly monogamous, but to-day, owing to the slaughter of the male birds, a polygamous state has developed. I believe also that limited polygamy in nature can develop into increased polygamy under certain forms of selection, as for example in the case of sheep. The herds of wild sheep in the Rockies are constituted in the proportion of one male to eight females, but in the sheep flocks in this country the average is about one male to 30 females. The introduction of an additional ram to flocks of sheep results in interference with the number of lambs produced, and similarly one finds that in a pigeon loft, free cock birds will materially affect the breeding in that loft—three odd cocks will ruin the breeding of three nests. In a poultry yard excess of cock birds will materially interfere with, if not entirely stop, the laying of eggs by the hens of that community. (In this connection 1 am informed that the male bird of the Jungle Fowl controls four or five hens, whilst in the ordinary domestic variety the hens may number up to 20.) For somewhat similar reasons cock pheasants must not be in excess in the nesting season, so they are shot off whilst the hen birds are spared at the end of the ^shooting season. Also a comparatively small proportion of males among guinea pigs kept in confinement together results in a reduction in numbers bred and the final extinction of the females. These facts tend to show that sexual relationship can b.e extended from the limited range to the wider range, but when once the wider range has become established, reduction of females and proportionate increase of males results in conditions which are unfavourable to the procreation of the species. 13 It is on facts somewhat similar to the above that it is suggested that if the sex relationship of rats could be interfered with more permanent benefits would accrue than from the capture and slaughter of all rats irrespective of sex. Apparently rats exist in nature in the ratio of about seven males to ten females. I have, however, not been able to obtain any considerable series of numbers which would support this ratio. Mr. Jennison has favoured me with the sexes of the rats which have been raptured at the Zoological Gardens, Manchester, during recent years, and these are as follows:— Year. Date. Captures. Males. Females. Total. 1915 October 11th to December 31st 40 45 85 1916 January to June 86 82 168 July to December 50 92 142 1917 January to June 60 84 144 July to December 72 135 207 1918 January to June 35 104 139 July to December 37 56 93 1919 January to June 40 68 108 July to December 55 50 105 Additional. Totals 475 716 1,191 1920 January 10 6 16 February ------ 7 8 15 (Recent newspaper reports have stated that of 72 rats caught by the Sissinghurst (Kent) Rat Club the proportion of females to males was seven to one.) If these figures are calculated on the basis of seven males to ten females, it will be seen that males are slightly fewer than they ought to be. For every 475 males there ought to be caught only 680 females, as compared with 716 shown above. The increase of females over males is possibly due to the fact that all females caught are killed whilst the males are turned down, and the male is naturally reluctant at returning to the trap. Comparatively few males appear twice in the traps, though occasionally odd ones will return three or more times. In general one would expect that proportionately more males would be caught than females, since sexual instincts would cause the male to have a wider range of 0 . journeying than the female, who is more frequently held up by care of young. (32) The position is then that more females exist than males, and it is assumed, if the males were turned down and the females slaughtered, that in the course of time the sex relationship would be so disturbed that males would be sufficiently in excess to harass females. This harassing would result in smaller litters, possible destruction of young, possible high mortality amongst females and possibly the development of cannibalism. It appears to me quite clear that if the male rats were turned down, apart from the damage done by such male rats, very little harm would result to the human community, since it is on the number and fecundity of females that the increase in the rat population depends, and the addition of a considerable number of males would certainly not result in any additional increase as a consequence of their release. It is further suggested that a rat once caught and turned down will only rarely return to the trap and may leave the district, but even in such a case he would increase the number of males in the adjoining area. It is a point of interest worthy of mention that Mr. Jennison reports "that in one trap the captures average little more than half those taken in 1915, this trap has been used 40 years and the captures at that time were evidently the normal." 14 Whether it is a practical proposition to disturb the sex ratio I have no evidence to guide me, but I do think that it is worthy of consideration even to the selection of a definite and reasonably circumscribed area in which experiments of this character could be undertaken.* I believe that scientific opinion is against the possibility of such a proposal proving practicable, nevertheless it indicates a suggestion sufficient for my present purpose, which is to emphasise that the subject of rat repression is one well worthy of serious research in many directions. (38) CONCLUSIONS.—(i.) In addition to the Corporation endeavouring to rid the sewers under their control of rats and also of preventing spare land and empty buildings in their possession from becoming rat-infested, supervision should be exercised to ensure that infested private premises are dealt with energetically. To enable this work to be undertaken in a systematic and uniform manner throughout the City, three inspectors additional to the one now employed on this work should be appointed. (ii.) Attempts should be made to formulate a scheme of registration of rat-catchers with the City Authorities, and the basis of registration should be compliance with certain rules formulated by the Corporation after conference with such men as are engaged in this work in the City. (iii.) Occupiers of premises should be asked to employ only such rat-catchers as are registered, provided these arrangements are made. (iv.) Discouragement should be given to the use of viruses in places were there is any probability of food contamination resulting. (v.) The Government should be asked to undertake investigation work with a view to ascertaining whether danger exists to public health as a result of rats becoming the carriers of the infection contained in the different proprietary viruses. (vi.) The use of poisons should be discouraged inside premises where people are engaged, and particularly in those where rats breed and pass their lives as opposed to those to which rats gain access from a permanent resort outside the premises. The better plan is to use some method which will enable the bodies of captured rats to be removed, as by the use of suitable traps, varnish or other adhesive material spread on cardboards, or by the employment of rat-catchers. (vii.) Poisoning by various methods is most suitable for ridding open spaces or sewers of rats. (viii.) Rat repressive measures should be on the lines laid down in paragraph (vi.) in markets and open spaces where food is stored. (ix.) Energies should be displayed throughout the year and not sporadically. (x.) The question of offering payment for rats caught might be well considered. If this principle is put into operation certain fundamental controls will require to be devised. Since this Report was completed a circular letter has been received from the Ministry of Agriculture and Fisheries, in which one paragraph reads as follows:— "When the Rats and Mice (Destruction) Act, 1919, became law on the 1st January "the question was raistd as to the legality of the payment under Section 2 (2) of the Act "of rewards by Local Authorities for rats killed, and this Ministry were informed by the "Ministry of Health that they had considered the matter and that it did not appear "to them that the Act empowered a Local Authority to pay rewards for the destruction * The Calf of Man, which Mr. Jennison believes is rat-infested, he considers would be an excellent area for the purpose. % / 15 (xi.) The attention of the occupiers of premises within the City should be directed to their new obligations under the Rats and Mice (Destruction) Act, 1919, by means of posters left at the different premises, and they should be helped in their efforts by supplying them free with information as to how to deal with the problem. The distribution of copies of this Report, perhaps, might be serviceable. (xii.) The Government should undertake research work with a view to ascertaining whether some measures cannot be discovered which will offer a chance of more permanent results accruing than will follow the practice of dealing with rat-infested places as outlined above. I have the honour to be, Gentlemen, Your obedient Servant, (Signed) WILLIAM J. HOWARTH, Medical Officer of Health. 16 APPENDICES. APPENDIX A.—Copy of Poster recommended for use by Ministry of Agriculture. Do. B.—Copy of Official Notice as set out by Ministry of Agriculture to be served under Rats and Mice (Destruction) Act, 1919 (Section 5). Do. C.—Recipes for the use of Barium Carbonate. Do. D — Recipe for the use of Scilla Maritima. Do. E.—Information respecting the Mongoose. 17 Appendix A. FORM OF POSTER ADVOCATED BY THE MINISTRY OF AGRICULTURE. RATS AND MICE (DESTRUCTION) ACT, 1919. This Act comes into operation on 1st January, 1920. PENALTIES FOR FAILURE TO DESTROY RATS AND MICE. Any person who shall fail to take such steps as may from time to time be necessary and reasonably practicable for the destruction of rats and mice on or in any land of which he is the Occupier, or for preventing such land from becoming infested with rats and mice, shall be liable on summary conviction to a fine not exceeding Five Pounds, or where he has been served with a Notice under this Act requiring him to take such steps, not exceeding Twenty Pounds. The expression "Occupier" means, in the case of land not occupied by any Tenant or other person, the Owner of the land. The expression "Land" includes any buildings, and any other erection on land, and any cellar, sewer, drain or culvert in or under land. This Act shall apply to a Vessel as if the Vessel were "Land," and the Master of the Vessel shall be deemed to be the "Occupier" thereof. Methods and Preventive Measures. The most effective methods for destroying rats and mice embrace the use of traps, snares, ferrets, dogs, fumigation, and the use of poisons. The safest poisons have been found to be preparations of Squills and Barium Carbonate. Poison should be laid in such a way that human beings, domestic animals, poultry, &c., cannot obtain access to it. The laying of baits containing any poison should be carried out with the utmost care. The actual amount laid in each single rat-hole or burrow should be as small as possible to obtain the results aimed at. The position of these places should be noted, and any dead rats found afterwards should be burnt or destroyed to prevent domestic animals getting at, the carcases. Previous to the laying of poisons the owners of poultry, dogs, pigs, and other animals frequenting or likely to come near places where poison has been laid should be warned, and, after an interval of a few days, all unconsumed baits should be removed and destroyed. Attention should be specially directed to all drains, waste, food and grain stores and stacks, &c. Before threshing commences sacks should be surrounded with fine meshed wire, not less than four feet in height, to prevent rats escaping. Persons desiring information on the subject of rat or mice destruction, or experiencing any difficulty in obtaining suitable materials for that purpose, should apply to* to whom all complaints should be addressed. * Insert here Name and Address of the Officer appointed by the Local Authority to enforce the Act. 18 Appendix B. FORM OF NOTICE AS LAID DOWN BY THE MINISTRY OF AGRICULTURE. RATS AND MICE (DESTRUCTION) ACT, 1919. (Section 5.) To Sir/Madam, I am directed by the to inform you that they are of opinion that you have failed to take such steps as are necessary and reasonably practicable for the destruction of rats/mice on or in the lands and buildings in your occupation known as and for preventing such premises becoming infested with rats/mice, and that the Council under the above-mentioned Act require you to take the following steps for such purposes, viz.:—You are required within days from the date hereof If you fail to comply with this direction, you will be liable on conviction to a penalty of twenty pounds, and the Council will have power to enter on the said premises and carry out the above directions and to recover from you any reasonable expenses so incurred by the Council which are directly attributable to your default. I am, Sir/Madam, Your obedient Servant, Clerk to the Council. Appendix C. RECIPES FOR THE USE OF BARIUM CARBONATE AS ADVOCATED BY THE MINISTRY OF AGRICULTURE. 1. Barium Carbonate 6 ozs. Meal 16 ozs. Dripping 4 ozs. Salt 1/2 oz. This makes 1,000 baits of 6 grains each (i.e., pieces as large as a hazel nut). 2. Barium Carbonate 4 ozs. Biscuit meal or plain meal 4 ozs. Oil of Aniseed 5 drops. Mix with fat to a paste, and lay out in places where rats are known to be present, in pieces the size of a hazel nut. 3. Tallow 50 per cent. Barium Carbonate (Ba2 C03). 50 per cent. Mix with dripping to a thick paste and spread on cubes of bread the size of a dice. 19 Appendix D. RECIPE FOR THE USE OF SCILLA MARITIMA AS ADVOCATED BY THE MINISTRY OF AGRICULTURE. SCILLA MARITIMA PREPARATION. A well-known Continental way of destroying rodents is to bake a pancake—egg pancake not essential, but beef dripping advisable—to whicb 20 per cent, of finely chopped Scilla Maritima, red variety, is added, either to the batter before frying, which is simpler, or placed between two layers of pancake after frying. When cold the pancake should be cut into pieces of abouT ½ inch square and laid in the rat runs or holes. Rats are particularly susceptible to the effects of Scilla Maritima (Squills). If squills in the bulbous form is not obtainable, a solution of squills is manufactured by amongst others, Haller and Company, 325, Borough High Street, S.E. 1, who can give information as to its application in the liquid state. Appendix E. THE MONGOOSE OR ICHNEUMON. Contributed by G. Jennison, Esq., Zoological Gardens, Manchester. The mongoose has a very large range over the warmer parts of India, Egypt and Africa generally and varies in size from the Egyptian, which weighs almost as much as a cat, to the Indian which is usually about the size of a large rat, and can therefore follow the rodents into their holes. They are all of a brownish colour, sharp-nosed, exceedingly quick in their movements, yet withal susceptible of being tamed. The Egvptian variety was and, I believe, still is domesticated to serve the purpose of a cat. The Indian—''Herpestes griseus "—with which alone we need concern ourselves, is the Rikki-Tikki of Kipling —the soldiers' pet of most Indian battalions. It is very abundant, and for a regular trade should be obtainable in London at £1 a head. Exceedingly courageous and bloodthirty, it will catch and kill all kinds of small mammals and birds, and even poultry, so that it cannot be used against rats in country districts. Its vaiue as a rat destroyer was first discovered in the West Indies, where nine were introduced in 1872 to help in the struggle against the rodents in the sugar plantations—they multiplied exceedingly, and were so efficacious that in ten years they were saving £200,000 a year to the planters. Their success was their discomfiture, the rats, driven by persecution, became arboreal—the mongoose, unable to follow them, turned upon the poultry and in their turn have become a pest. The West Indian experiment introduced them to England. About 1894 a prize of £20 was offered by a Manchester newspaper for the best method of clearing warehouses of rats—one competitor suggested the mongoose, and on a favourable report from the Zoological Gardens, Belle Vue, Manchester, he received the prize, and Mr. Cross, Naturalist, Liverpool, was inundated with enquiries for the beast, which was at once • extensively employed and is still in demand tor the purpose. To newspaper enquiries, would the mongoose do what was required and could it be easily kept we replied that we had used the 20 mongoose with marked effect, as an ordinary ferret, to which it is vastly superior, but its extraordinary quickness made it dangerous to handle. It is best left to do its own hunting, which should be arranged as follows :— Obtain a box about 2 ft. by 1 ft. by 1 ft., cover the front with 1 in. mesh netting, the door being of the same material. Place a little hay or other litter in one corner of the box and keep the place clean. Put the box in a damp- and draught- free corner of the infested warehouse if possible where the sunshine may reach it—feed the animal on small quantities of perfectly fresh meat, also a little ripe fruit—oranoes are special favourites—give water to drink and leave the animal there for a week to get used to its quarters. At the end of that time open the door late in the evening and let the mongoose find its way out. In the morning it will be gone and may not be seen for weeks, but a little fresh meat and fruit, also water, should be placed daily in the box as a temptation to return. It will return from time to time, but will finally disappear, lost or strayed, from two to six months after release, having appreciably earned far more than its cost. If necessary purchase another. Being entirely fearless, active and bloodthirsty the mongoose kills many rats, but in my mind it is chiefly effective in scaring them from the neighbourhood.