,transcriber's ,note3 ,the following suspected errors have been changed in this text3 ,page #f3 highdays changed to highways ,page #aa3 abbatoirs changed to abattoirs ,page #aa3 ,added missing 4 to ,,fig4 #e4 ,page #ad3 ,added missing 4 to ,,fig4 #aj4 ,,house ,,rats ,,and ,,mice ,,david ,e4 ,,lantz ,assistant ,biologist ,illustration ,,farmers' ,,bulletin #hif ,,united ,,states ,,department ,,of ,,agriculture 99 99 99 99 99 ,contribution from the ,bureau of ,biological ,survey ,e4 ,w4 ,,nelson1 ,chief ,washington1 ,d4 ,c4 ,october1 #aiag ,show this bulletin to a neighbor4 ,additional copies may be obtained free from the ,division of ,publications1 ,united ,states ,department of ,agriculture ,,washington3 ,,government ,,printing ,,office3 #aiag ,the rat is the worst animal pest in the world4 ,from its home among filth it visits dwellings and storerooms to pollute and destroy human food4 ,it carries bubonic plague and many other diseases fatal to man and has been responsible for more untimely deaths among human beings than all the wars of history4 ,in the ,united ,states rats and mice each year destroy crops and other property valued at over #bjj1jjj1jjj4 ,this destruction is equivalent to the gross earnings of an army of over #bjj1jjj men4 ,on many a farm1 if the grain eaten and wasted by rats and mice could be sold1 the proceeds would more than pay all the farmer's taxes4 ,the common brown rat breeds #f to #aj times a year and produces an average of #aj young at a litter4 ,young females breed when only three or four months old4 ,at this rate a pair of rats1 breeding uninterruptedly and without deaths1 would at the end of three years 7#ah generations7 be increased to #cei1gji1dhb individuals4 ,for centuries the world has been fighting rats without organization and at the same time has been feeding them and building for them fortresses for concealment4 ,if we are to fight them on equal terms we must deny them food and hiding places4 ,we must organize and unite to rid communities of these pests4 ,the time to begin is now4 ,,house ,,rats ,,and ,,mice4 ,,contents4 ,page4 ,destructive habits #c ,protection of food and other stores #e ,rat-proof building #e ,keeping food from rats and mice #i ,destroying rats and mice #aa ,traps #aa ,poisons #ae ,domestic animals #ah ,fumigation #ah ,rat viruses #ai ,natural enemies #bj ,organized efforts to destroy rats #bj ,community efforts #ba ,state and national aid #ba ,important repressive measures #bc ,,destructive ,,habits ,,of ,,house ,,rats ,,and ,,mice4 ,losses from depredations of house rats amount to many millions of dollars yearly--to more1 in fact1 than those from all other injurious mammals combined4 ,the common house mouse#a and the brown rat#b 7fig4 #a71 too familiar to need description1 are pests in nearly all parts of the country2 while two other kinds of house rats1 known as the black rat#c and the roof rat1#d are found within our borders4 ,illustration3 ,,fig4 #a4--;,brown rat4 ,of these four introduced species--for none is native to ,america--the brown rat is the most destructive1 and1 except the mouse1 the most numerous and most widely distributed4 ,brought to ,america just before the ,revolution1 it has supplanted and nearly exterminated its less robust relative the black rat2 and in spite of the constant warfare of man has extended its range and steadily increased in numbers4 ,its dominance is due to its great fecundity and its ability to adapt itself to all sorts of surroundings4 ,it breeds 7in the middle part of the ,united ,states7 six or more times a year and produces from #f to #bj young 7average #aj7 in a litter4 ,females breed when only #c or #d months old4 ,thus a pair1 breeding uninterruptedly and without deaths1 could in three years 7#ah generations7 produce a posterity of #cei1gji1dhj individuals4 ,mice and the black and roof rats produce smaller litters1 but the period of gestation1 about #ba days1 and the number of litters are the same for all4 ,rats and mice are practically omnivorous1 feeding upon all kinds of animal and vegetable matter4 ,the brown rat makes its home in the open field1 the hedge row1 and the river bank1 as well as in stone walls1 piers1 and all kinds of buildings4 ,it destroys grains when newly planted1 while growing1 and in the shock1 stack1 mow1 crib1 granary1 mill1 elevator1 or ship's hold1 and also in the bin and feed trough4 ,it invades store and warehouse and destroys furs1 laces1 silks1 carpets1 leather goods1 and groceries4 ,it attacks fruits1 vegetables1 and meats in the markets1 and destroys by pollution ten times as much as it actually eats4 ,it destroys eggs and young poultry1 and eats the eggs and young of song and game birds4 ,it carries disease germs from house to house and bubonic plague from city to city4 ,it causes disastrous conflagrations2 floods houses by gnawing lead water pipes2 ruins artificial ponds and embankments by burrowing2 and damages foundations1 floors1 doors1 and furnishings of dwellings4 ,unlike the brown rat the black rat rarely migrates to the fields4 ,it has disappeared from most parts of the ,northern ,states1 but is occasionally found in remote villages or farms4 ,at our seaports it frequently arrives on ships from abroad1 but seldom becomes very numerous4 ,the roof rat is common in many parts of the ,south1 where it is a persistent pest in cane and rice fields4 ,it maintains itself against the brown rat partly because of its habit of living in trees4 ,the common house mouse by no means confines its activities to the inside of buildings1 but is often found in open fields1 where its depredations in shock and stack are well known4 ,not only are mice and rats1 especially the brown rat1 a cause of destruction and damage to property1 but they are also a constant menace to the health of man4 ,it has been proved that they are the chief means of perpetuating and transmitting bubonic plague and that they play important roles in conveying other diseases to human beings4 ,they are parasites1 without redeeming characteristics1 and should everywhere be routed and destroyed4 ,,protection ,,of ,,food ,,and ,,other ,,stores ,,from ,,rats ,,and ,,mice4 ,past attempts to exterminate rats and mice have failed1 not so much because of lack of effective means as because of the neglect of necessary precautions and the absence of concerted endeavors4 ,we have rendered our work abortive by continuing to provide subsistence and hiding places for the animals4 ,if these advantages are denied1 persistent and general use of the usual methods of destruction will prove far more successful4 ,,rat-,,proof ,,building4 ,first in importance1 as a measure of rat repression1 is the exclusion of the animals from places where they find food and safe retreats for rearing their young4 ,the best way to keep rats from buildings1 whether in city or in country1 is to use cement in construction4 ,as the advantages of this material are coming to be generally understood1 its use is rapidly extending to all kinds of buildings4 ,the processes of mixing and laying this material require little skill or special knowledge1 and workmen of ordinary intelligence can successfully follow the plain directions contained in handbooks of cement construction4#e ,many modern public buildings are so constructed that rats can find no lodgment in the walls or foundations1 and yet in a few years1 through negligence1 such buildings often become infested with the pests4 ,sometimes drain pipes are left uncovered for hours at a time4 ,often outer doors1 especially those opening on alleys1 are left ajar4 ,a common mistake is failure to screen basement windows which must be opened for ventilation4 ,however the intruders are admitted1 when once inside they intrench themselves behind furniture or stores1 and are difficult to dislodge4 ,the addition of inner doors to vestibules is an important precaution against rats4 ,the lower edge of outer doors to public buildings1 especially markets1 should be reinforced with light metal plates to prevent the animals from gnawing through4 ,any opening left around water1 steam1 or gas pipes1 where they go through walls1 should be closed carefully with concrete to the full depth of the wall4 ,dwellings4--,in constructing dwelling houses the additional cost of making the foundations rat-proof is slight compared with the advantages4 ,the cellar walls should have concrete footings1 and the walls themselves should be laid in cement mortar4 ,the cellar floor should be of medium rather than lean concrete4 ,even old cellars may be made rat-proof at comparatively small expense4 ,rat holes may be permanently closed with a mixture of cement1 sand1 and broken glass1 or sharp bits of crockery or stone4 ,on a foundation like the one described above1 the walls of a wooden dwelling also may be made rat-proof4 ,the space between the sheathing and lath1 to the height of about a foot1 should be filled with concrete4 ,rats can not then gain access to the walls1 and can enter the dwelling only through doors or windows4 ,screening all basement and cellar windows with wire netting is a most necessary precaution4 ,old buildings in cities4--,aside from old dwellings1 the chief refuges for rats in cities are sewers1 wharves1 stables1 and outbuildings4 ,modern sewers are used by the animals merely as highways and not as abodes1 but old-fashioned brick sewers often afford nesting crannies4 ,illustration3 ,,fig4 #b4--,rat-proofing a frame dwelling by concrete side wall 7,united ,states ,public ,health ,service1 ,new ,orleans1 ,la41 #aiad74 ,wharves1 stables1 and outbuildings in cities should be so built as to exclude rats4 ,cement is the chief means to this end4 ,old tumble-down buildings and wharves should not be tolerated in any city4 7,see fig4 #b47 ,in both city and country1 wooden floors of sidewalks1 areas1 and porches are commonly laid upon timbers resting on the ground4 ,under such floors rats have a safe retreat from nearly all enemies4 ,the conditions can be remedied in towns by municipal action requiring that these floors be replaced by others made of cement4 ,areas or walks made of brick are often undermined by rats and may become as objectionable as those of wood4 ,wooden floors of porches should always be well above the ground4 ,farm buildings4--,granaries1 corncribs1 and poultry houses may be made rat-proof by a liberal use of cement in the foundations and floors2 or the floors may be of wood resting upon concrete4 ,objection has been urged against concrete floors for horses1 cattle1 and poultry1 because the material is too good a conductor of heat1 and the health of the animals suffers from contact with these floors4 ,in poultry houses1 dry soil or sand may be used as a covering for the cement floor1 and in stables a wooden floor resting on concrete is just as satisfactory so far as the exclusion of rats is concerned4 ,the common practice of setting corncribs on posts with inverted pans at the top often fails to exclude rats1 because the posts are not high enough to place the lower cracks of the structure beyond reach of the animals4 ,as rats are excellent jumpers1 the posts should be tall enough to prevent the animals from obtaining a foothold at any place within #c feet of the ground4 ,a crib built in this way1 however1 is not very satisfactory4 ,for a rat-proof crib a well-drained site should be chosen4 ,the outer walls1 laid in cement1 should be sunk about #bj inches into the ground4 ,the space within the walls should be grouted thoroughly with cement and broken stone and finished with rich concrete for a floor4 ,upon this the structure may be built4 ,even the walls of the crib may be of concrete4 ,corn will not mold in contact with them1 provided there is good ventilation and the roof is water-tight4 ,however1 there are cheaper ways of excluding rats from either new or old corncribs4 ,rats1 mice1 and sparrows may be kept out effectually by the use of either an inner or an outer covering of galvanized-wire netting of half-inch mesh and heavy enough to resist the teeth of the rats4 ,the netting in common use in screening cellar windows is suitable for covering or lining cribs4 ,as rats can climb the netting1 the entire structure must be screened1 or1 if sparrows are not to be excluded1 the wire netting may be carried up about #c feet from the ground1 and above this a belt of sheet metal about a foot in width may be tacked to the outside of the building4 ,complete working drawings for the practical rat-proof corncrib shown in figures #c and #d may be obtained from the ,office of ,public ,roads and ,rural ,engineering of the department4 ,buildings for storing foodstuffs4--,whenever possible1 stores of food for man or beast should be placed only in buildings of rat-proof construction1 guarded against rodents by having all windows near the ground and all other possible means of entrance screened with netting made of ,no4 #ah or ,no4 #bj wire and of #a_/d-;inch mesh4 ,entrance doors should fit closely1 should have the lower edges protected by wide strips of metal1 and should have springs attached1 to insure that they shall not be left open4 ,before being used for housing stores1 the building should be inspected as to the manner in which water1 steam1 or gas pipes go through the walls1 and any openings found around such pipes should be closed with concrete4 ,illustration3 ,,fig4 #c4--,perspective of rat-proof corncrib1 showing concrete foundation by dotted lines2 also belt of metal4 ,if rat-proof buildings are not available1 it is possible1 by the use of concrete in basements and the other precautions just mentioned1 to make an ordinary building practically safe for food storage4 ,when it is necessary to erect temporary wooden structures to hold forage1 grain1 or food supplies for army camps1 the floors of such buildings should not be in contact with the ground1 but elevated1 the sills having a foot or more of clear space below them4 ,smooth posts rising #b or #c feet above the ground may be used for foundations1 and the floor itself may be protected below by wire netting or sheet metal at all places where rats could gain a foothold4 ,care should be taken to have the floors as tight as possible1 for it is chiefly scattered grain and fragments of food about a camp that attract rats4 ,rat-proofing by elevation4--,the ,united ,states ,public ,health ,service reports that in its campaigns against bubonic plague in ,san ,francisco 7#aijg7 and ,new ,orleans 7#aiad7 many plague rats were found under the floors of wooden houses resting on the ground4 ,these buildings were made rat-proof by elevation1 and no case of either human or rodent plague occurred in any house after the change4 ,placing them on smooth posts #ah inches above the ground1 with the space beneath the floor entirely open1 left no hiding place for rats4 ,this plan is adapted to small dwellings throughout the ,south1 and to small summer homes1 temporary structures1 and small farm buildings everywhere4 ,wherever rats might obtain a foothold on the top of the post they may be prevented from gnawing the adjacent wood by tacking metal plates or pieces of wire netting to floor or sill4 ,,keeping ,,food ,,from ,,rats ,,and ,,mice4 ,the effect of an abundance of food on the breeding of rodents should be kept in mind4 ,well-fed rats mature quickly1 breed often1 and have large litters4 ,poorly fed rats1 on the contrary1 reproduce less frequently and have smaller litters4 ,in addition1 scarcity of food makes measures for destroying the animals far more effective4 ,merchandise in stores4--,in all parts of the country there is a serious economic drain in the destruction by rats and mice of merchandise held for sale by dealers4 ,not only foodstuffs and forage1 but textiles1 clothing1 and leather goods are often ruined4 ,this loss is due mainly to the faulty buildings in which the stores are kept4 ,often it would be a measure of economy to tear down the old structures and replace them by new ones4 ,however1 even the old buildings may often be repaired so as to make them practically rat-proof2 and foodstuffs1 as flour1 seeds1 and meats1 may always be protected in wire cages at slight expense4 ,the public should be protected from insanitary stores by a system of rigid inspection4 ,illustration3 ,,fig4 #d4--;,floor plan of rat-proof corncrib shown in figure #c4 ,household supplies4--,similar care should be exercised in the home to protect household supplies from mice and rats4 ,little progress in ridding the premises of these animals can be made so long as they have access to supplies of food4 ,cellars1 kitchens1 and pantries often furnish subsistence not only to rats that inhabit the dwelling1 but to many that come from outside4 ,food supplies may always be kept from rats and mice if placed in inexpensive rat-proof containers covered with wire netting4 ,sometimes all that is needed to prevent serious waste is the application of concrete to holes in the basement wall or the slight repair of a defective part of the building4 ,produce in transit4--,much loss of fruits1 vegetables1 and other produce occurs in transit by rail and on ships4 ,most of the damage is done at wharves and in railway stations1 but there is also considerable in ships' holds1 especially to perishable produce brought from warm latitudes4 ,much of this may be prevented by the use of rat-proof cages at the docks1 by the careful fumigation of seagoing vessels at the end of each voyage1 and by the frequent fumigation of vessels in coastwise trade2 but still more by replacing old and decrepit wharves and station platforms with modern ones built of concrete4 ,where cargoes are being loaded or unloaded at wharves or depots1 food liable to attack by rats may be temporarily safeguarded by being placed in rat-proof cages1 or pounds1 constructed of wire netting4 ,wooden boxes containing reserve food held in depots for a considerable time or intended for shipment by sea may be made rat-proof by light coverings of metal along the angles4 ,this plan has long been in use to protect naval stores on ships and in warehouses4 ,it is based on the fact that rats do not gnaw the plane surfaces of hard materials1 but attack doors1 furniture1 and boxes at the angles only4 ,packing houses4--,packing houses and abattoirs are often sources from which rats secure subsistence1 especially where meats are prepared for market in old buildings4 ,in old-style cooling rooms with double walls of wood and sawdust insulation1 always a source of annoyance because of rat infestation1 the utmost vigilance is required to prevent serious loss of meat products4 ,on the other hand1 packing houses with modern construction and sanitary devices have no trouble from rats or mice4 ,garbage and waste4--,since much of the food of rats consists of garbage and other waste materials1 it is not enough to bar the animals from markets1 granaries1 warehouses1 and private food stores4 ,garbage and offal of all kinds must be so disposed of that rats can not obtain them4 ,in cities and towns an efficient system of garbage collection and disposal should be established by ordinances4 ,waste from markets1 hotels1 cafes and households should be collected in covered metal receptacles and frequently emptied4 ,garbage should never be dumped in or near towns1 but should be utilized or promptly destroyed by fire4 ,rats find abundant food in country slaughterhouses2 reform in the management of these is badly needed4 ,such places are centers of rat propagation4 ,it is a common practice to leave offal of slaughtered animals to be eaten by rats and swine1 and this is the chief means of perpetuating trichinae in pork4 ,the law should require that offal be promptly cremated or otherwise disposed of4 ,country slaughterhouses should be as cleanly and as constantly inspected as abattoirs4 ,another important source of rat food is found in remnants of lunches left by employees in factories1 stores1 and public buildings4 ,this food1 which alone is sufficient to attract and sustain a small army of rats1 is commonly left in waste baskets or other open receptacles4 ,strictly enforced rules requiring all remnants of food to be deposited in covered metal vessels would make trapping far more effective4 ,illustration3 ,,fig4 #e4--;,guillotine trap made entirely of metal4 ,military training camps1 unless subjected to rigid discipline in the matter of disposal of garbage and waste1 soon become centers of rat infestation4 ,waste from camps1 deposited in covered metal cans and collected daily1 should be removed far from the camp itself and either burned or utilized in approved modern ways4 ,,destroying ,,rats ,,and ,,mice4 ,the ,biological ,survey has made numerous laboratory and field experiments with various agencies for destroying rats and mice4 ,the results form the chief basis for the following recommendations3 ,,traps4 ,owing to their cunning1 it is not always easy to clear rats from premises by trapping2 if food is abundant1 it is impossible4 ,a few adults refuse to enter the most innocent-looking trap4 ,and yet trapping1 if persistently followed1 is one of the most effective ways of destroying the animals4 ,guillotine trap4--,for general use the improved modern traps with a wire fall released by a baited trigger and driven by a coiled spring have marked advantages over the old forms1 and many of them may be used at the same time4 ,these traps1 sometimes called guillotine traps1 are of many designs1 but the more simply constructed are preferable4 ,probably those made entirely of metal are the best1 as they are more durable4 ,traps with tin or sheet-metal bases are not recommended4 ,guillotine traps of the type shown in figure #e should be baited with small pieces of ,vienna sausage 7,wienerwurst7 or fried bacon4 ,a small section of an ear of corn is an excellent bait if other grain is not present4 ,the trigger wire should be bent inward to bring the bait into proper position for the fall to strike the rat in the neck1 as shown in figure #f4 ,other excellent baits for rats and mice are oatmeal1 toasted cheese1 toasted bread 7buttered71 fish1 fish offal1 fresh liver1 raw meat1 pine nuts1 apples1 carrots1 and corn1 and sunflower1 squash1 or pumpkin seeds4 ,broken fresh eggs are good bait at all seasons1 and ripe tomatoes1 green cucumbers1 and other fresh vegetables are very tempting to the animals in winter4 ,when seed1 grain1 or meal is used with a guillotine trap1 it is put on the trigger plate1 or the trigger wire may be bent outward and the bait placed directly under it4 ,oatmeal 7rolled oats7 is recommended as a bait for guillotine traps made with wooden base and trigger plate 7fig4 #g74 ,these traps are especially convenient to use on ledges or other narrow rat runs or at the openings of rat burrows4 ,they are often used without bait4 ,illustration3 ,,fig4 #f4--,method of baiting guillotine trap4 ,a common mistake in trapping for rats and mice is to use only one or two traps when dozens are needed4 ,for a large establishment hundreds of traps may be used to advantage1 and a dozen is none too many for an ordinary barn or dwelling infested with rats4 ,house mice are less suspicious than rats and are much more easily trapped4 ,small guillotine traps baited with oatmeal will soon rid an ordinary dwelling of the smaller pests4 ,cage trap4--,when rats are abundant1 the large ,french wire cage traps may be used to advantage4 ,they should be made of stiff wire1 well reinforced4 ,many of those sold in stores are useless1 because a full-grown rat can bend the light wires apart and so escape4 ,illustration3 ,,fig4 #g4--;,guillotine trap with wooden base and trigger plate4 ,cage traps may be baited and left open for several nights until the rats are accustomed to enter them to obtain food4 ,they should then be closed and freshly baited1 when a larger catch may be expected1 especially of young rats 7fig4 #h74 ,as many as #be1 and even more1 partly grown rats have been taken at a time in one of these traps4 ,it is better to cover the trap than to leave it exposed4 ,a short board should be laid on the trap and an old cloth or bag or a bunch of hay or straw thrown carelessly over the top4 ,often the trap may be placed with the entrance opposite a rat hole and fitting it so closely that rats can not pass through without entering the trap4 ,if a single rat is caught it may be left in the trap as a decoy to others4 ,notwithstanding the fact that sometimes a large number of rats may be taken at a time in cage traps1 a few good guillotine traps intelligently used will prove more effective in the long run4 ,illustration3 ,,fig4 #h4--;,cage trap with catch of rats4 ,figure-#d trigger trap4--,the old-fashioned box trap set with a figure-#d trigger is sometimes useful to secure a wise old rat that refuses to be enticed into a modern trap4 ,better still is a simple deadfall--a flat stone or a heavy plank--supported by a figure-#d trigger4 ,an old rat will go under such a contrivance to feed without fear4 ,steel trap4--,the ordinary steel trap 7,no4 #j or #a7 may sometimes be satisfactorily employed to capture a rat4 ,the animal is usually caught by the foot1 and its squealing has a tendency to frighten other rats4 ,the trap may be set in a shallow pan or box and covered with bran or oats1 care being taken to have the space under the trigger pan free of grain4 ,this may be done by placing a very little cotton under the trigger and setting as lightly as possible4 ,in a narrow run or at the mouth of a burrow a steel trap unbaited and covered with very light cloth or tissue paper is often effective4 ,illustration3 ,,fig4 #i4--;,barrel trap3 #a1 ,with stiff paper cover2 #b1 with hinged barrel cover2 a1 stop2 b1 baits4 ,the best bait usually is food of a kind that the rats and mice do not get in the vicinity4 ,in a meat market1 vegetables or grain should be used2 in a feed store1 meat4 ,as far as possible food other than the bait should be inaccessible while trapping is in progress4 ,the bait should be kept fresh and attractive1 and the kind changed when necessary4 ,baits and traps should be handled as little as possible4 ,illustration3 ,,fig4 #aj--,pit trap4 aa1 ,rat run2 bb1 cover2 cc1 position of weights2 dd1 rods on which covers turn4 ,barrel trap4--,about #fj years ago a writer in the ,cornhill ,magazine gave details of a trap1 by means of which it was claimed that #c1jjj rats were caught in a warehouse in a single night4 ,the plan involved tolling the rats to the place and feeding them for several nights on the tops of barrels covered with coarse brown paper4 ,afterwards a cross was cut in the paper1 so that the rats fell into the barrel 7fig4 #i 7#a774 ,many variations of the plan1 but few improvements upon it1 have been suggested by agricultural writers since that time4 ,reports are frequently made of large catches of rats by means of a barrel fitted with a light cover of wood1 hinged on a rod so as to turn with the weight of a rat 7fig4 #i 7#b774 ,pit trap4--,a modification of the barrel trap is the pit trap 7fig4 #aj74 ,this consists of a stout narrow box sunk in the ground so that the top is level with the rat run4 ,it is fixed with a cover of light wood or metal in two sections1 the sections fitting nicely inside the box and working independently4 ,they turn on rods1 to which they are fastened4 ,they are weighted near the ends of the box and so adjusted that they swing easily4 ,an animal stepping upon the cover beyond the rods is precipitated into the box1 while the cover immediately swings back to its place4 ,besides rats1 the trap is well adapted to capture larger animals1 as minks1 raccoons1 opossums1 and cats4 ,it is especially useful to protect poultry yards1 game preserves1 and the like4 ,the trap should be placed along the fence outside the yard1 and behind a shelter of boards or brush that leans against the fence4 ,fence and battue4--,in the rice fields of the ,far ,east the natives build numerous piles of brush and rice straw1 and leave them for several days until many rats have taken shelter in them4 ,a portable bamboo inclosure several feet in height is then set up around each pile in succession and the straw and brush are thrown out over the top1 while dogs and men kill the trapped rodents4 ,large numbers are destroyed in this way1 and the plan with modifications may be utilized in ,america with satisfactory results4 ,a wire netting of fine mesh may be used for the inclosure4 ,the scheme is applicable at the removal of grain1 straw1 or haystacks1 as well as brush piles4 ,in a large barn near ,washington1 a few years ago1 piles of unhusked corn were left in the loft and were soon infested with rats4 ,a wooden pen was set down surrounding the piles in turn and the corn thrown out until dogs were able to get at the rats4 ,in this way several men and dogs killed #ejj rats in a single day4 ,,poisons4 ,while the use of poison is the best and quickest way to get rid of rats and mice1 the odor from the dead animals makes the method impracticable in occupied houses4 ,poisons may be effectively used in barns1 stables1 sheds1 cribs1 and other outbuildings4 ,caution4--,in the ,united ,states there are few laws which prohibit the laying of poisons on lands owned or controlled by the poisoner4 ,hence it is all the more necessary to exercise extreme caution to prevent accidents4 ,in several ,states notice of intention to lay poison must be given to persons living in the neighborhood4 ,poison for rats should never be placed in open or unsheltered places4 ,this applies particularly to strychnin or arsenic on meat4 ,packages containing poisons should always bear a warning label and should not be kept where children might reach them4 ,among the principal poisons that have been recommended for killing rats and mice are barium carbonate1 strychnin1 arsenic1 phosphorus1 and squills4 ,barium carbonate4--,one of the cheapest and most effective poisons for rats and mice is barium carbonate4 ,this mineral has the advantage of being without taste or smell4 ,it has a corrosive action on the mucous lining of the stomach and is dangerous to larger animals if taken in sufficient quantity4 ,in the small doses fed to rats and mice it would be harmless to domestic animals4 ,its action upon rats is slow1 and if exit is possible the animals usually leave the premises in search of water4 ,for this reason the poison may frequently1 though not always1 be used in houses without disagreeable consequences4 ,barium carbonate may be fed in the form of dough composed of four parts of meal or flour and one part of the mineral4 ,a more convenient bait is ordinary oatmeal with about one-eighth of its bulk of the mineral1 mixed with water into a stiff dough4 ,a third plan is to spread the barium carbonate upon fish1 toasted bread 7moistened71 or ordinary bread and butter4 ,the prepared bait should be placed in rat runs1 about a teaspoonful at a place4 ,if a single application of the poison fails to kill or drive away all rats from the premises1 it should be repeated with a change of bait4 ,strychnin4--,strychnin is too rapid in action to make its use for rats desirable in houses1 but elsewhere it may be employed effectively4 ,strychnia sulphate is the best form to use4 ,the dry crystals may be inserted in small pieces of raw meat1 ,vienna sausage1 or toasted cheese1 and these placed in rat runs or burrows2 or oatmeal may be moistened with a strychnin sirup and small quantities laid in the same way4 ,strychnin sirup is prepared as follows3 ,dissolve a half ounce of strychnia sulphate in a pint of boiling water2 add a pint of thick sugar sirup and stir thoroughly4 ,a smaller quantity may be prepared with a proportional quantity of water and sirup4 ,in preparing the bait it is necessary to moisten all the oatmeal with the sirup4 ,wheat and corn are excellent alternative baits4 ,the grain should be soaked overnight in the strychnin sirup4 ,arsenic4--,arsenic is probably the most popular of the rat poisons1 owing to its cheapness1 yet our experiments prove that1 measured by the results obtained1 arsenic is dearer than strychnin4 ,besides1 arsenic is extremely variable in its effect upon rats1 and if the animals survive a first dose it is very difficult to induce them to take another4 ,powdered white arsenic 7arsenious acid7 may be fed to rats in almost any of the baits mentioned under barium carbonate and strychnin4 ,it has been used successfully when rubbed into fresh fish or spread on buttered toast4 ,another method is to mix twelve parts by weight of corn meal and one part of arsenic with whites of eggs into a stiff dough4 ,an old formula for poisoning rats and mice with arsenic is the following1 adapted from an ,english source3 ,take a pound of oatmeal1 a pound of coarse brown sugar1 and a spoonful of arsenic4 ,mix well together and put the composition into an earthen jar4 ,put a tablespoonful at a place in runs frequented by rats4 ,phosphorus4--,for poisoning rats and mice1 phosphorus is used almost as commonly as arsenic1 and undoubtedly it is effective when given in an attractive bait4 ,the phosphorus paste of the drug stores is usually dissolved yellow phosphorus1 mixed with glucose or other substances4 ,the proportion of phosphorus varies from one-fourth of #a per cent to #d per cent4 ,the first amount is too small to be always effective and the last is dangerously inflammable4 ,when homemade preparations of phosphorus are used there is much danger of burning the person or of setting fire to crops or buildings4 ,in the ,western ,states many fires have resulted from putting out homemade phosphorus poisons for ground squirrels1 and entire fields of ripe grain have been destroyed in this way4 ,even with commercial pastes the action of sun and rain changes the phosphorus and leaches out the glucose until a highly inflammable residue is left4 ,it is often claimed that phosphorus eaten by rats or mice dries up or mummifies the body so that no odor results4 ,the statement has no foundation in fact4 ,no known poison will prevent decomposition of the body of an animal that died from its effects4 ,equally misleading is the statement that rats poisoned with phosphorus do not die on the premises4 ,owing to its slower operation1 no doubt a larger portion escape into the open before dying than when strychnin is used4 ,the ,biological ,survey does not recommend the use of phosphorus as a poison for rodents4 ,squills4--,the squill1 or sea leek1#f is a favorite rat poison in many parts of ,europe and is well worthy of trial in ,america4 ,it is rapid and very deadly in its action1 and rats seem to eat it readily4 ,the poison is used in several ways4 ,two ounces of dry squills1 powdered1 may be thoroughly mixed with eight ounces of toasted cheese or of butter and meal and put out in runs of rats or mice4 ,another formula recommends two parts of squills to three parts of finely chopped bacon1 mixed with meal enough to make it cohere4 ,this is baked in small cakes4 ,poison in poultry houses4--,for poisoning rats in buildings and yards occupied by poultry the following method is recommended3 ,two wooden boxes should be used1 one considerably larger than the other and each having one or more holes in the sides large enough to admit rats4 ,the poisoned bait should be placed on the bottom and near the middle of the smaller box1 and the larger box should then be inverted over it4 ,rats thus have free access to the bait1 but fowls are excluded4 ,,domestic ,,animals4 ,among domestic animals employed to kill rats are the dog1 the cat1 and the ferret4 ,dogs4--,the value of dogs as ratters can not be appreciated by persons who have had no experience with a trained animal4 ,the ordinary cur and the larger breeds of dogs seldom develop the necessary qualities for ratters4 ,small ,irish1 ,scotch1 and fox terriers1 when properly trained1 are superior to other breeds and under favorable circumstances may be relied upon to keep the farm premises reasonably free from rats4 ,cats4--,however valuable cats may be as mousers1 few learn to catch rats4 ,the ordinary house cat is too well fed and consequently too lazy to undertake the capture of an animal as formidable as the brown rat4 ,birds and mice are much more to its liking4 ,cats that are fearless of rats1 however1 and have learned to hunt and destroy them are often very useful about stables and warehouses4 ,they should be lightly fed1 chiefly on milk4 ,a little sulphur in the milk at intervals is a corrective against the bad effects of a constant rat or mouse diet4 ,cats often die from eating these rodents4 ,ferrets4--,tame ferrets1 like weasels1 are inveterate foes of rats1 and can follow the rodents into their retreats4 ,under favorable circumstances they are useful aids to the rat catcher1 but their value is greatly overestimated4 ,for effective work they require experienced handling and the additional services of a dog or two4 ,dogs and ferrets must be thoroughly accustomed to each other1 and the former must be quiet and steady instead of noisy and excitable4 ,the ferret is used only to bolt the rats1 which are killed by the dogs4 ,if unmuzzled ferrets are sent into rat retreats1 they are apt to make a kill and then lie up after sucking the blood of their victim4 ,sometimes they remain for hours in the burrows or escape by other exits and are lost4 ,there is danger that these lost ferrets may adapt themselves to wild conditions and become a pest by preying upon poultry and birds4 ,,fumigation4 ,rats may be destroyed in their burrows in the fields and along river banks1 levees1 and dikes by carbon bisulphid4#g ,a wad of cotton or other absorbent material is saturated with the liquid and then pushed into the burrow1 the opening being packed with earth to prevent the escape of the gas4 ,all animals in the burrow are asphyxiated4 ,fumigation in buildings is not so satisfactory1 because it is difficult to confine the gases4 ,moreover1 when effective1 the odor from the dead rats is highly objectionable in occupied buildings4 ,chlorin1 carbon monoxid1 sulphur dioxid1 and hydrocyanic acid are the gases most used for destroying rats and mice in sheds1 warehouses1 and stores4 ,each is effective if the gas can be confined and made to reach the retreats of the animals4 ,owing to the great danger from fire incident to burning charcoal or sulphur in open pans1 a special furnace provided with means for forcing the gas into the compartments of vessels or buildings is generally employed4 ,hydrocyanic-acid gas is effective in destroying all animal life in buildings4 ,it has been successfully used to free elevators and warehouses of rats1 mice1 and insects4 ,however1 it is so dangerous to human life that the novice should not attempt fumigation with it1 except under careful instructions4 ,directions for preparing and using the gas may be found in a publication entitled ,hydrocyanic-acid ,gas against ,household ,insects1 by ,dr4 ,l4 ,o4 ,howard and ,charles ,h4 ,popenoe4#h ,carbon monoxid is rather dangerous1 as its presence in the hold of a vessel or other compartment is not manifest to the senses1 and fatal accidents have occurred during its employment to fumigate vessels4 ,chlorin gas has a strong bleaching action upon textile fabrics1 and for this reason can not be used in many situations4 ,sulphur dioxid also has a bleaching effect upon textiles1 but less marked than that of chlorin1 and ordinarily it is not noticeable with the small percentage of the gas it is necessary to use4 ,on the whole1 this gas has many advantages as a fumigator and disinfectant4 ,it is used also as a fire extinguisher on board vessels4 ,special furnaces for generating the gas and forcing it into the compartments of ships and buildings are on the market1 and many steamships and docks are now fitted with the necessary apparatus4 ,,rat ,,viruses4 ,several microorganisms1 or bacteria1 found originally in diseased rats or mice1 have been exploited for destroying rats4 ,a number of these so-called rat viruses are on the ,american market4 ,the ,biological ,survey1 the ,bureau of ,animal ,industry1 and the ,united ,states ,public ,health ,service have made careful investigations and practical tests of these viruses1 mostly with negative results4 ,the cultures tested by the ,biological ,survey have not proved satisfactory4 ,the chief defects to be overcome before the cultures can be recommended for general use are3 #a4 ,the virulence is not great enough to kill a sufficiently high percentage of rats that eat food containing the microorganisms4 #b4 ,the virulence decreases with the age of the cultures4 ,they deteriorate in warm weather and in bright sunlight4 #c4 ,the diseases resulting from the microorganisms are not contagious and do not spread by contact of diseased with healthy animals4 #d4 ,the comparative cost of the cultures is too great for general use4 ,since they have no advantages over the common poisons1 except that they are usually harmless to man and other animals1 they should be equally cheap2 but their actual cost is much greater4 ,moreover1 considering the skill and care necessary in their preparation1 it is doubtful if the cost can be greatly reduced4 ,the ,department of ,agriculture1 therefore1 does not prepare1 use1 or recommend the use of rat viruses4 ,,natural ,,enemies ,,of ,,rats ,,and ,,mice4 ,among the natural enemies of rats and mice are the larger hawks and owls1 skunks1 foxes1 coyotes1 weasels1 minks1 dogs1 cats1 and ferrets4 ,probably the greatest factor in the increase of rats1 mice1 and other destructive rodents in the ,united ,states has been the persistent killing off of the birds and mammals that prey upon them4 ,animals that on the whole are decidedly beneficial1 since they subsist upon harmful insects and rodents1 are habitually destroyed by some farmers and sportsmen because they occasionally kill a chicken or a game bird4 ,the value of carnivorous mammals and the larger birds of prey in destroying rats and mice should be more fully recognized1 especially by the farmer and the game preserver4 ,rats actually destroy more poultry and game1 both eggs and young chicks1 than all the birds and wild mammals combined2 yet some of their enemies among our most useful birds of prey and carnivorous mammals are persecuted almost to the point of extinction4 ,an enlightened public sentiment should cause the repeal of all bounties on these animals and afford protection to the majority of them4 ,,organized ,,efforts ,,to ,,destroy ,,rats4 ,the necessity of cooperation and organization in the work of rat destruction is of the utmost importance4 ,to destroy all the animals on the premises of a single farmer in a community has little permanent value1 since they are soon replaced from near-by farms4 ,if1 however1 the farmers of an entire township or county unite in efforts to get rid of rats1 much more lasting results may be attained4 ,if continued from year to year1 such organized efforts are very effective4 ,,community ,,efforts4 ,cooperative efforts to destroy rats have taken various forms in different localities4 ,in cities1 municipal employees have occasionally been set at work hunting rats from their retreats1 with at least temporary benefit to the community4 ,thus1 in #aijd1 at ,folkestone1 ,england1 a town of about #be1jjj inhabitants1 the corporation employees1 helped by dogs1 in three days killed #a1fde rats4 ,side hunts in which rats are the only animals that count in the contest have sometimes been organized and successfully carried out4 ,at ,new ,burlington1 ,ohio1 a rat hunt took place some years ago in which each of the two sides killed over #h1jjj rats1 the beaten party serving a banquet to the winners4 ,there is danger that organized rat hunts will be followed by long intervals of indifference and inaction4 ,this may be prevented by offering prizes covering a definite period of effort4 ,such prizes accomplish more than municipal bounties1 because they secure a friendly rivalry which stimulates the contestants to do their utmost to win4 ,in ,england and some of its colonies contests for prizes have been organized to promote the destruction of the ,english1 or house1 sparrow1 but many of the so-called sparrow clubs are really sparrow and rat clubs1 for the destruction of both pests is the avowed object of the organizations4 ,a sparrow club in ,kent1 ,england1 accomplished the destruction of #bh1jjj sparrows and #af1jjj rats in three seasons by the annual expenditure of but ,l#f 7#bi4bj7 in prize money4 ,had ordinary bounties been paid for this destruction1 the tax on the community would have been about ,l#bej 7over #a1bjj74 ,many organizations already formed should be interested in destroying rats4 ,boards of trade1 civic societies1 and citizens' associations in towns and farmers' and women's clubs in rural communities will find the subject of great importance4 ,women's municipal leagues in several large cities already have taken up the matter4 ,the league in ,baltimore recently secured appropriations of funds for expenditure in fighting mosquitoes1 flies1 and rats4 ,the league in ,boston during the past year1 supported by voluntary contributions for the purpose1 made a highly creditable educational campaign against rats4 ,boys' corn clubs1 the troops of ,boy ,scouts1 and similar organizations could do excellent work in rat campaigns4 ,,state ,,and ,,national ,,aid4 ,to secure permanent results any general campaign for the elimination of rats must aim at building the animals out of shelter and food4 ,building reforms depend on municipal ordinances and legislative enactments4 ,the recent plague eradication work of the ,united ,states ,public ,health ,service in ,san ,francisco1 ,seattle1 ,new ,orleans1 and at various places in ,hawaii and ,porto ,rico required such ordinances and laws as well as financial aid in prosecuting the work4 ,the campaign of ,danish and ,swedish organizations for the destruction of rats had the help of governmental appropriations4 ,the legislatures of ,california1 ,texas1 ,indiana1 and ,hawaii have in recent years passed laws or made appropriations to aid in rat riddance4 ,it is probable that well-organized efforts of communities would soon win legislative support everywhere4 ,communities should not postpone efforts1 however1 while waiting for legislative cooperation1 but should at once organize and begin repressive operations4 ,wherever health is threatened the ,public ,health ,service of the ,united ,states can cooperate1 and where crops and other products are endangered the ,bureau of ,biological ,survey of the ,department of ,agriculture is ready to assist by advice and in demonstration of methods4 ,,important ,,repressive ,,measures4 ,the measures needed for repressing and eliminating rats and mice include the following3 #a4 ,the requirement that all new buildings erected shall be made rat-proof under competent inspection4 #b4 ,that all existing rat-proof buildings shall be closed against rats and mice by having all openings accessible to the animals1 from foundation to roof1 closed or screened by door1 window1 grating1 or meshed wire netting4 #c4 ,that all buildings not of rat-proof construction shall be made so by remodeling1 by the use of materials that may not be pierced by rats1 or by elevation4 #d4 ,the protection of our native hawks1 owls1 and smaller predatory mammals--the natural enemies of rats4 #e4 ,greater cleanliness about markets1 grocery stores1 warehouses1 courts1 alleys1 stables1 and vacant lots in cities and villages1 and like care on farms and suburban premises4 ,this includes the storage of waste and garbage in tightly covered vessels and the prompt disposal of it each day4 #f4 ,care in the construction of drains and sewers1 so as not to provide entrance and retreat for rats4 ,old brick sewers in cities should be replaced by concrete or tile4 #g4 ,the early threshing and marketing of grains on farms1 so that stacks and mows shall not furnish harborage and food for rats4 #h4 ,removal of outlying straw stacks and piles of trash or lumber that harbor rats in fields and vacant lots4 #i4 ,the keeping of provisions1 seed grain1 and foodstuffs in rat-proof containers4 #aj4 ,keeping effective rat dogs1 especially on farms and in city warehouses4 #aa4 ,the systematic destruction of rats1 whenever and wherever possible1 by 7a7 trapping1 7b7 poisoning1 and 7c7 organized hunts4 #ab4 ,the organization of clubs and other societies for systematic warfare against rats4 ,,footnotes3 #a ,mus musculus4 #b ,rattus norvegicus4 #c ,rattus rattus rattus4 #d ,rattus rattus alexandrinus4 #e ,farmers' ,bulletin #dfa1 ,use of ,concrete on the ,farm1 will prove useful to city and village dwellers as well as to the farmer4 #f ,scilla maritima4 #g ,,caution4--,carbon disulphid is very inflammable and can be ignited by a match1 lantern1 cigar1 or pipe4 #h ,farmers' ,bulletin #fii4 ,,publications ,,of ,,the ,,united ,,states ,,department ,,of ,,agriculture ,,relating ,,to ,,noxious ,,mammals4 ,,available ,,for ,,free ,,distribution4 ,how to ,destroy ,rats4 7,farmers' ,bulletin #cfi47 ,the ,common ,mole of ,eastern ,united ,states4 7,farmers' ,bulletin #ehc47 ,field ,mice as ,farm and ,orchard ,pests4 7,farmers' ,bulletin #fgj47 ,cottontail ,rabbits in ,relation to ,trees and ,farm ,crops4 7,farmers' ,bulletin #gjb47 ,trapping ,moles and ,utilizing ,their ,skins4 7,farmers' ,bulletin #hcb47 ,destroying ,rodent ,pests on the ,farm4 7,separate #gjh1 ,yearbook for #aiaf47 ,,for ,,sale ,,by ,,the ,,superintendent ,,of ,,documents1 ,,government ,,printing ,,office1 ,,washington1 ,d4 ,c4 ,harmful and ,beneficial ,mammals of the ,arid ,interior1 with ,special ,reference to the ,carson and ,humboldt ,valleys1 ,nevada4 7,farmers' ,bulletin #cce47 ,price #e cents4 ,the ,nevada ,mouse ,plague of #aijg-h4 7,farmers' ,bulletin #ceb47 ,price #e cents4 ,some ,common ,mammals of ,western ,montana in ,relation to ,agriculture and ,spotted ,fever4 7,farmers' ,bulletin #dhd47 ,price #e cents4 ,danger of ,introducing ,noxious ,animals and ,birds4 7,separate #acb1 ,yearbook #ahih47 ,price #e cents4 ,meadow ,mice in ,relation to ,agriculture and ,horticulture4 7,separate #chh1 ,yearbook #aije47 ,price #e cents4 ,mouse ,plagues1 ,their ,control and ,prevention4 7,separate #dhb1 ,yearbook #aijh47 ,price--cents4 ,use of ,poisons for ,destroying ,noxious ,mammals4 7,separate #dia1 ,yearbook #aijh47 ,price #e cents4 ,pocket ,gophers as ,enemies of ,trees4 7,separate #ejf1 ,yearbook #aiji47 ,price #e cents4 ,the ,jack ,rabbits of the ,united ,states4 7,biological ,survey ,bulletin #h47 ,price #aj cents4 ,economic ,study of ,field ,mice1 genus ,microtus4 7,biological ,survey ,bulletin #ca47 ,price #ae cents4 ,the ,brown ,rat in the ,united ,states4 7,biological ,survey ,bulletin #cc47 ,price #ae cents4 ,directions for the ,destruction of ,wolves and ,coyotes4 7,biological ,survey ,circular #ee47 ,price #e cents4 ,the ,california ,ground ,squirrel4 7,biological ,survey ,circular #gf47 ,price #e cents4 ,seed-eating ,mammals in ,relation to ,reforestation4 7,biological ,survey ,circular #gh47 ,price #e cents4 ,mammals of ,bitterroot ,valley1 ,montana1 in ,their ,relation to ,spotted ,fever4 7,biological ,survey ,circular #hb47 ,price #e cents4