DATE DUE DAR 4 4634-<- + ; hs | GAYLORD PRINTED IN U.S.A. Library Cornell University Library SF 808.16 3 nT 1924 003 272 014 "12 Ne ‘L¥d : roe Yashoeshg sloxeaL “aug “soi1g p1ojAed Japulg yoiydued PUNOWIOJOUE aan A PLAIN. STATEMENT OF FACTS REGARDING TH DISEASE ae 8 ‘oA FOR FARMERS AND. orumees - , _ INTRESTED IN LIVE STOCK | ony ‘yuk pan COMMISSION ON THE poo - - OE! BOVINE B TUBERCULOSIS Bel -oPnawa” fede Te i | ‘eg “GOVERNMENT PRINTING. BUREAU: . ie Agu SE at, os Cornell University The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003272014 TUBERCULOSIS A PLAIN STATEMENT OF FACTS REGARDING THE DISEASE PREPARED ESPECIALLY FOR FARMERS AND OTHERS INTERESTED IN LIVE STOCK BY THE INTERNATIONAL COMMISSION ON THE CONTROL OF BOVINE TUBERCULOSIS OTTAWA GOVERNMENT PRINTING BUREAU 1911 11015—1 ay] Orrawa, November 1, 1911. Srr,—I have the honour to present herewith a brief compilation of useful facts regarding animal Tuberculosis for the special information of farmers and others interested in live stock. This treatise, which is devoid of technical terms, has been prepared by the International Commission on the Control of Bovine Tuberculosis, as a supple- ment to its first report, it being thought desirable to disseminate, as widely as possible, among those most concerned, accurate information regarding the disease. I would recommend that this be printed for general distribution. I have the honour to be, sir, Your obedient servant, J. G. RUTHERFORD, Veterinary Director General and Live Stock Commissioner. To the Honourable Martin Burren, Minister of Agriculture, Ottawa, Ont. 11015—14 TABLE OF CONTENTS Cleanliness.. .. .. Bes skeet arid Gh ap ena pc yay pleNieaae tates Gay aves ABO Destine: with: a badly mfceted end. Saute sane Ssatte ha hh Tite ee eR ee le HG Drainage... .. ... bigs ends Mt ae See ate Cee edgy gs Oa awe ed ee eet ee cee, 70 Pissury al this dikesse Diabetes oh at eta te nk Ry cS lek! athe Cola Jake gales soe alate eek th 7 How a herd is infected... .. 2. 6. 06 ce ce ee ee ee ee ne ee ee ee ee QO How the disease spreads.. .. .. pete hee ae wets eae aw ae ae aay ea’. 20 Importance of the disease.. .. 2. 6. ce ce ee ee ce te ee ee ee ee ee ee 610 ihetter. of tranemiittalee ae cad shea yen od ee Gea Re Rie SRS PA ee ee a 3 Members of the International Commission on the Gouge of ee fitenca: losis.. .. .. Se Wide Sod hes Wah lasitee Wie Mebeosaa dik Cada Revit EY she Gees, Comee mee secre, sell Nehuce. oF Thadikcecas: hs ated Wace ste tem Gain eae rity eh estat Cha ene oa Ate Oc ahah a ie cal 7 Post mortem appearances... .. 1... 6 ee ee et ee ee ee ee ee 16 Man GAG OM no. ete usaes wececnhee encase Seer otgts Gunning aed ota CAN Rea ee ea. asi ae. take lt = EBD) Gace cities eee Sac Mg Gils id Grew ay Ree tee? Bi Ske ee a wa oe ee DA DYMPLOMISY. 4: GA te uae geek ter ke a ek Sah Ge ee a ee 13 Duberculitiis: a: cte ice jay dee aes de ae oe Be Re A ae ee es a ee. 222 Tuberculin test.. .. .. .. eed soce! ee ds seta be tet, Uae ae, acme oct het laa ODE OM Tuberculin test, reliability ~ Sinton Ges Bam gas teen aie: aes aaa asel un) Serta cditin BOD Tuberculin test, limitations of.. 2. 6. 6. 6. ee ce ee ee ee ee ee ee ee ee OA VieTItI At OM ais: Ga hae tel ast Sec Pr Pee Poke, ee Sede oo th sted A OS) sede oes Sl eel cous, “OD TUBERCULOSIS FACTS FOR FARMERS AND OTHERS ABOUT THIS DISEASE. Tuberculosis is a widespread disease affecting animals and also man. Human beings and cattle are its chief. victims, but there is no kind of animal that will not take it. Hogs and chickens are quite often affected; horses, sheep and goats but seldom, while cattle are the most susceptible of all animals. NATURE OF THE DISEASE. Tuberculosis is contagious or “ catching.” It spreads from cow to cow in a herd until most of them are affected. This may not attract much notice from the owner as the disease is slow to develop and a cow may be affected with it for several months, and sometimes years, before any signs of ill health are to be seen. This slow development is the chief reason for the great loss it causes to the farmer. He does not suspect its presence in his herd until perhaps a large rumber are diseased. If the disease developed rapidly and caused death in a few days, the owner would soon take steps to check its progress and protect the rest of his herd. Tuberculosis is slow and hidden in its course and thus arouses no suspicion until great damage is done. HISTORY. Where did tuberculosis come from? We do not know. History records it from the earliest times. Over a century ago, its contagious nature was suspected and many facts were recorded to prove that it must be “catching.” Doctors differed about it, and for a long time the question was hotly disputed. Finally it was settled by Dr. Robert Koch, a distinguished German physician, who discovered the germ of the disease in the year 1882, and named it Bacillus Tuberculosis. He proved by experiment that the disease is produced by these germs and with- out them the disease cannot be produced. It is now universally admitted that tuberculosis is a contagious disease and may be transmitted from animal to man. 7 “Soapeo INOJ 09 YRIIG Weal sey oYs pasedsip st M09 ay] YVYy UmoUy suredaq 4s1y 41 sou ‘stad’ aay asvay ye Apoq sey woay suLIeS Slso[Mosaqny Jo siaqiunu o8avy Surssed useq’ pry sys eya pur sive moj 4svoy ye. snofnoseqny uaeq pey oYs 9VY} UMOUY seam 41 Uayey sem oangord Joy owl eq dyW “ALU Jo A4qrQuenb aBzey ATPensnun ue Seals pue snosoSIA pue Jucays surees ays ‘poos Ss! e}yedde zoey ‘y8noo_jou seop sys ‘Ayyvey Atquasedde sr oangord eaoqe 94} Ul UMOYs Mod BYTE —"T ‘ON “41 ya 0} poyqitased a19Mm yeyy s80y UL stso[nodaqny pesnvo einqord yxoU ey. UI UMOYS MOO ayy Jo PU AD SITY JO Sunp poxtur ot], *savod aaryy gsveT 4% Apoq Jey Woay suIIEs stsopnoseqny Sutssed wseq pey oys 4eq9 puv sav INOJ qsvOT 48 SISOTNOIEqNy YALA peyoeye useq pey oys yey UMOUY se 41 UOYye, sem oaNgoId soy auI1y ey4 ay ‘Moo Lirep ¥ 10} UOTFTPUOD [eAoUS quUATa0Xe UI st pu y[ruL Jo AyWUENd a8iv] B said oys ‘pos st oytyodde say ‘y8noo you saop ayg “AYgTeey ApjUeredde si ornqoid aaoge oy} Ul UMOYS MOD BYT—"G “ON 2 11015 10 In America the disease was introduced with early importations of cattle and has been with us ever since. Modern methods of transportation by rail and water have spread the disease from one end of the continent to the other. No part of the country is entirely free from it, but it is more prevalent near the great centres of population than in the remoter parts. IMPORTANCE. The importance of the disease must be estimated from two points of view, first, the loss it entails upon the cattle owner, and second, the danger of com- munication to human beings. Consider first its effect upon the pocket of the owner of cattle, whether farmer, breeder or dairyman. A serious percentage of the dairy cows of the continent are affected and the disease is found in even a larger percentage of dairy herds. The disease is commoner in some regions than in others. It is no uncommon thing to find as many as 70 per cent or 80 per cent of the cows in a herd diseased. These animals will be in various stages of the disease, some recently infected showing no sign of ill health, others badly diseased, but outwardly appearing healthy, while a few are evidently breaking down and wasting away. The loss to the owner is evident when a cow dies of the disease, or when an apparently healthy cow is slaughtered for beef and found so badly affected as to be unfit for food. The calves in such a herd do not long remain healthy. They catch the disease before many months old and are a source of loss instead of gain. Although the disease is most frequently found in herds that are more or less closely confined, such as dairy herds and pure bred cattle, other herds are by no means free from it. Even range cattle are sometimes affected and the infection spreads in spite of the open air life of the cattle. Tuberculosis is common among hogs. The public abattoirs report that a serious percentage of all hogs inspected is found to be tuberculous. The aggregate of these losses among cattle and hogs is enormous, amount- ing to millions of dollars every year, besides materially decreasing the food supply of the country. Turning to the other aspect of the case, the danger of infection of human beings with tuberculosis from cattle, we have only to consider a few facts to realize its vital importance to every community. Milk is the staple food of infants and young children and is usually taken in the raw state. If this milk is from a tuberculous cow, it may contain mil- lions of living tubercle germs. Young children fed on such milk often contract the disease, and it is a frequent cause of death among them. Meat from tuberculous cattle is not so likely to convey the infection for several reasons. It does not so frequently contain the germs, cooking destroys those that may be present, and lastly, meat is not consumed by very young children. 11 “41 ¥9 04 poyqtutted alam 4ey9 soy Ul slso[noiaqny pasnes eangoid qsey ayy UL UMOYs BuO OY4 JO PUR MOO S14) Jo JuNp pextu au, “ULYS I19Yy} Jepun peoed sem 41 vay ssid vous ut sisopnoreqny pasnvo Sunp Jay jo seryiquenb TTeurg ‘stv9d ano} yseT BY} UL psonpoad sey Ys YIANOJ 949 SI apIs J8Y Aq j[vo oy, ‘amy Buoy & 10j Apoq Jey Wo4d] suIaS sisofMoseqny suissed useq pey ays yeYyR pu sivok Fp qsvey ye SIsoTMoIEqny YIIM peqyooye useq pey oYs yey} UMOTY sem 4 UeHe) Sem oansord Jay OUlly AYA YW “poare A[}US00I SB 4VY9 MOO HTLU B OF YUT[edxXe SI UOIPUOD [eI9UeS Joy pure poos st eqyadde a9q ‘ysnoo you seop ayg ‘AyaTeay Apueredde si oinqoid sty UL UMOYs MOO BUT—"E ‘ON, 24 11015 12 ‘passed Suteq alam SULIOS asvasIp ayy syaqrenb mojz 94 Jo yoy WOIT [2d PINoe qzedxa ue 4eYy YI Jay Jo $3739} [NJoavo 4ySOUuL AY JO SYQUOUT OMY JaAze ATWO SEAL 4I PUB PASVASIP SBA IL 4VY} MOYS 0} Japph Joy yHoqe v[qIstA SuIyIOU svm oIOYT, ‘SULLA sisopNo1eqna peureytos Moo ay} JO YLIWA ayy IVYY puNoJ sea qT VEYLZ sem oAngoId Joy orozeq sIBed FZ yNOQW “snopnoraqny auredeq Sunp 194 Yea 07 poeyyiutsed saa 4eyy s8oy pue Sunp 1oy UT PUNO; a19M SUITES sIso[Nodaqny uayey sem ainjoid ray asojoq saved aif, “saved INO UVYZ eIOUT sisopNoIEqny YA poqyoage woaq svy yevyy [UIITY Ue IOF WOTYTPUOD 4U9T]9dX9 UT st eAngord styy UL UMOYSs M09 oY —"F ‘ON 18 SYMPTOMS. Before describing the symptoms or signs by which tuberculosis is recog- nized or suspected in a living animal, it is well to state that there is no symptom that can be relied on with certainty. Any of the symptoms may sometimes be caused by some other disease, and not one of them is characteristic of tubercu- losis alone. Many of the symptoms that are relied on by the human physician in reaching his opinion are not available in examining cattle. The thickness of the skin and chest wall, for instance, makes it difficult to detect a diseased condition of their lings by listening to the sounds made in breathing, whereas this is comparatively easy in human beings. It must also be clearly remembered that cattle may be very badly diseased and yet show no symptoms of ill health. They may be fat and sleek, looking the picture of health, while their lungs and other organs are full of tubercles. Such cases can only be detected by the tuberculin test. As tuberculosis may attack almost any organ of the body, we may have in each case the symptoms ccnnected with the part affected, as well as those affecting the general state of the body as a whole. We will take up in detail each of the more important symptoms suggestive of the disease. Unthriftiness. The animal is not doing as well as it should for the care and feed it. is getting. Its coat is rough and its skin has lost its suppleness, and feels harsh and thick. Loss of Flesh. Along with the unthriftiness is noticed a gradual loss of flesh; the animal gets thinner from week to week. It appears to be pining away, and such cows have been known to dairymen for a long time under the name of “ piners,”’ o: “wasters.” After a time they are reduced almost to skin and bone. Cough. This symptom is only present when the disease is attacking the lungs or some part of the breathing organs. It is not a loud, sonorous cough, but rather a subdued and infrequent one, and may be heard only at such times as when the stable is first opened in the morning, or when the animal is driven. At a luter stage of the disease it may be heard at any time of the day. Cows do not usually appear to cough up anything. This is because they do not spit. Most of the material coughed up from the lungs is swallowed, but many tuber- culosis germs escape from the mouth in the form of spray or are discharged from the nose. 14 ‘S[VUUIUe aMOT pur suosied yyoq 10} snozeSuep 41 jo sfoy.m oyy ayeut TIM ‘smoo 1ey}O Jo YU 949 YIM pax ‘PON eangord aaoge ayy Ur esoyy ax] SMoo WOT Yl fo quNoUTe [[VUIs W “sIsoTNOJaq(ng savy 04 ULEIIO JSOUITY O18 OUITY [SUIS e ATUO SIappN sno[ror1eqny WoIy HI YULIp 07 pazqyitated ore qeyy Soayeo V4} JOR} OY} Wor] pespnl aq Avur sae aingord oy) UL eUO Oty OyT[ SMoo snoJeguep 419A MOF, “POSBEstp SEM FT ALTA MOYS 07 4SIY 4B Japp ayy Jo MOWIpUOD [euseyxo Jo soUvAvadde ayy ul Surqjou sem azoyy {ssid vauny OUT YALU Toy Jo oulos Zurjoalur Aq opeur sea AI@AOOSIp SIU, ‘SISOTMOTEQ Ny Tappa oavy 0} pataaoosip sv MOD ayy Uayey sv oangold saoqe ah a1ojaq weak V ‘Jopph yy Ul sSurpems snojmoseqnuy a8re] yar ‘stxopNo1aqny Jo aseo poeouva pe sulpueys SuUOT W—"G ‘ON, 15 “s[BUIIU IAMOT PUB SMOSIad Bund Ul EYT[E stsopnoreqny ese 09 4ydv As9A st ye4S ABI V UL YPLUL 119q4 JO osn OY4 PIV WAY YIIM yoRJUOO UT sUTCD ABUL 4VYY STVUIIUE JouyO 04 Je3UEp year 8 oR SMOD YONG “4SIseI uO sudsied OUIOS UY JOYveIs SI Y[IU Jey} ASN 0} puUe SMOD yous deey 07 uoyeydurey oy, ‘sproy Arlep UT snosetane 003 ApoyvuNgzojuN ore PUTY"sTYy JO SMOD “yjemr jo Aqtquenb yuvpunge uv sats 07 senulyu0S UOTpUOCD Yew JOY Ul pu Jey[IU Lavay @ st yng ‘UTYyy pus Yeam AJOA ST OYS “sTSOTMOITeqny JO eseo peouvape ue st aIngoid ay} UI Moo ey T—"9 “ON 16 Enlarged Glands. Enlargements in the region of the throat, especially when they cause difficulty in breathing, are very apt to be due to tuberculosis. Loss of Appetite. This symptom is not seen until the latter stages of the disease, when the animal is evidently wasting. Bloating. Sometimes the diseased glands in the chest prevent the usual passage of eas from the paunch to the mouth by pressing on the gullet. In this case the cow suffers from bloating and the paunch is often greatly distended with gas. This, however, is not a very frequent symptom. Diarrhea. Looseness of the bowels or “ scouring” is seen in cattle affected with the Cisease in the bowels. This kind of scouring cannot be cured by any known treatment. Hard Lumps in the Udder. When tuberculosis attacks the udder, no change can be detected at first, but after a time hard lumps can be felt in some parts of the organ after it is milked out. Milk from such an udder must not be used, as it is almost certain to be teeming with germs of the disease. POST MORTEM APPEARANCES. When the careass of a cow affected with tuberculosis is opened, the disease may be found in any part of the body. Lumps (tubercles) may be present in the substance of an organ such as the lung or liver, or they may be growing on the surface. These lumps may be so small as to be scarcely noticeable, or they may be as large as the closed fist, or even larger. If one of the lumps is cut open, the inside is yellowish and grits on the knife like sand, or else is of a cheesy nature, soft and creamy or hard and dry. | The lung is a favourite place for tubercles, and should always be examined. Lymph glands are often the seat of. tuberculous changes. When healthy a lymph gland is a little rounded body, not much larger than a good sized bean, the largest only the size of one’s thumb. They are found all through the body and when healthy are so small as to attract very little attention. Tuberculosis may cause them to grow to an enormous size, sometimes as large as a child’s head. In this condition they are similar to the tuberculous lumps already described. Those lying between the lungs and in the throat are tha rnost frequently affected. Tubercles may be found in any part of the body, glands, lungs, liver, bowels, kidneys, womb, udder and even bones. The muscles and skin are seldom affected. “4807 UI[horaqny 944 Jo djay ayy inoyyLA Yep sly asojaq’ payoadsns Useq eavy JoAau pfnom Apoq sIy Ul sisojnoseqny, jo eousseid ey, ‘w10} Aue ut UIvIZ OU pues adevioy YBnor ATU pay sem yey [EULIUY Ue 1OJ 4UAT]}aOxE ST UOLyIpUOD yUeredde sig pus ‘sqT OGS‘T peystam [[Nq ayy YIEp SITY Jo auIIy 941 4W “paswasIp o1aM JAAIT PUL STaMoq SLY Y{LA paqoeuu0d spue[s qdurdy oy [Te ATvvau yeyy ‘peuado sem poq sty uaym ‘punoj sea 41 sZanl sty a stsopno ~foqn} JO Sa[npou snoIsuNU OF UOIFIppe UI pu ‘pally sem oy UsYe} sv eIngord siy seyye ATQOoIIG ‘Apo sty Wosy suLIeS sisoTnoreqny Sutssed sem oy 4eyy UMOUY Sem 41 8q3¥ sIvad O93 PUB sho[Notaqn} oq 04 UMOUY 4SIG Sv oY 199je saved INO} ATIVE UOYe} SVM [[NQ OY4 Jo eangoid ey —") ‘ON 17 18 THE TUBERCLE BACILLUS. The germ of the disease, the tubercle bacillus, is a tiny, slender, rod- shaped body. Several thousands of them placed end to end would be needed to measure an inch, so that they are quite invisible to the naked eye. A powerful microscope is needed to see them. Once the bacillus has gained lodgment inside the body of an animal, it begins to grow and multiply. It gets longer, and when full grown, divides crosswise, making two out of one. Each of these goes through the same pro- cess, the two become four, the four eight, the eight sixteen, and so on indefi- nitely. This multiplication takes place quite rapidly when conditions are favour- able, a few hours only being required for the birth of each generation. Nature, however, does not permit this process to continue long without offering some resistance. The forces of the body are roused to action and a battle begins between the tissues of the body and the army of the invaders. The first line of defence is composed of the white cells of the blood which hurry to the scene of action and endeavour to destroy the invaders by eating them up. Sometimes they are successful and the bacilli are destroyed, the infection checked. Often they fail in their object and are themselves destroyed and the multiplication of the germs continues. The second line of defence is found by the cells of the tissue invaded by the germs. These cells arrange themselves in a circle around the germs and try to form a living wall between them and the rest of the body. This barrier gradually becomes thicker and thicker and forms a little hard lump or tubercle, from which the disease gets its name. If this wall is complete and successfully imprisons the bacilli, these gradually die and the disease in that particular spot is arrested. Frequently, however, both these safeguards are overcome. The germs break through the barriers and are carried in the blood stream or lymph chan- nels to other parts of the body. New points of attack are selected and the process begins again, but with less chance on the side of the animal. As the tubercles increase in number, the power of the body to grapple with them becomes less and less, and gradually the animal falls a prey to the disease. The tubercle bacillus does not multiply outside the body of an animal. It can live for a long time in favourable surroundings, such as dark and dirty stables. Sunlight soon destroys it. Freezing does not hurt it, but it can only stand a moderate amount of heat; exposure to 149 degrees Fahrenheit for twenty minutes kills it. Protected by a layer of dried mucus, such as is coughed up from the lungs, it withstands drying, light, and ordinary disin fectants, but is readily killed by steam or boiling water. 19 No. 8.—Sections of a tuberculous udder from a cow. Practically the whole of the udder from which the sections were taken was changed into tuberculous material. Long before tuberculous udders become as badly diseased as the condition shown in the picture the milk contains large numbers of tuberculosis germs and is very dangerous. A tuberculous udder may contain only a single small tuberculous swelling through which the milk becomes dangerously infected with tuber- culosis germs. 20 HOW THE DISEASE SPREADS. Sooner or later the tuberculous cow begins to give off the germs of tle disease. The germs escape by the mouth and nose, the bowels, in the milk, and in discharges from the genital organs. When the germs are being given off in any of these ways, the disease is known as open tuberculosis. Germs discharged from the mouth and nose are coughed up from the lungs and are sprayed over the food in front of the cow or are carried in the air for a time until they fall to the ground. Cows in adjoining stalls may tuke in these germs in the air they breathe or in the food they eat, and so con- tract the disease. Germs discharged from the bowels are mixed with the manure, and may infect cattle and hogs that are allowed to pick over the dung heap. The prac- tice of having hogs and cattle together in the same yard is sure to result in the infection of the hogs, if any of the cattle are affected. The germs in the manure come from matter that is coughed up and swallowed, and in some cases from tuberculosis in the bowels themselves. Manure containing tubercle germs may easily infect the milk. Particles of dried manure may fall into the milk pail from the skin of a dirty cow or be accidentally flicked off from the tail and fall into the milk. Straining the milk afterwards only removes the larger particles. The smaller ones, including the germs, remain in the milk. When the udder is tuberculous, the milk contains the germs in vast num-- bers. Such milk may look and taste perfectly good, but readily transmits the disease to young animals. It is very dangerous to children. Hogs and calves are very readily infected by it. HOW A HERD IS INFECTED. Tuberculosis may be introduced into a healthy herd in a number of ways: 1. By the purchase of a bull or other animal that is infected with the disease. This animal may be apparently healthy at the time of purchase, but if it contains the germs, the disease may develop and spread to other cattle. New animals should only be bought from a herd that is known to be healthy. 2. By feeding calves with milk, buttermilk, or whey that has come from tuberculous cows. A farmer may have a healthy herd, but if he brings home skim milk from a creamery and feeds it to his calves, he may give them the disease. Such milk should be rendered safe by boiling or pasteurizing it. 3. By showing cattle at fairs and exhibitions where no proper care is taken to keep out diseased stock, or to disinfect the stables. 4. By shipping animals in cars that have not been disinfected, as these inay have recently carried diseased cattle. 5. By allowing cattle to graze with diseased ones, or to come in contact with them over fences. 21 Osu asip eu Mos eangord ayy ut syred p aAINOTOD 4g 3, CAR “MOO T WA IOAT] SNOTNIIaqNy Jo SUCTIOIg 6 {e) N 22 THE TUBERCULIN TEST. Tuberculosis develops so slowly that in many cases it is months, and some- times years, before any symptoms are shown. During this period, the infected animals cannot be distinguished from the healthy in any ordinary way. There is a test, however, which does no harm to the healthy, yet detects the diseased ones practically without fail. This is known as the tuberculin test, because the substance used in making it is called tuberculin. WHAT IS TUBERCULIN? Tuberculin is a fluid containing the products of the tubercle germ without the germs themselves. As it contains no living germ, it cannot convey the disease. Great skill is required in its preparation. A special fluid (or culture medium) is prepared and the tubercle bacilli planted in it, great care being taken to keep all other germs out. The fluid is then placed in a special kind cf incubator and kept at the temperature of the animal body. Under these conditions, the germs grow and multiply. Gradually the fluid becomes filled with the products of the germs. When the right point is reached the fluid is heated sufficiently to kill the germs which are then strained out. The remain- ing fluid is tuberculin. Tuberculin does not harm healthy cattle, even in large doses, but on diseased animals it produces a marked effect. This is shown by a feverish attack which comes on about eight to twelve hours after the tuberculin is administered, lasts a few hours, and then subsides. This temporary fever is called the reaction, and animals which show it are called reactors. The value of the test lies in the fact that diseased animals react while healthy ones do not. RELIABILITY OF THE TEST. The tuberculin test in the hands of a competent and experienced man is much more accurate than any other method of detecting tuberculosis. The records of large numbers of tests made by Government officials show that, with certain precautions, it is accurate in 98 per cent of the reactions obtained. This gives a margin of a possible 2 per cent of error and this small number may be still further lessened by care in making the test. For practical purposes any animal that reacts must be considered tuberculous. 23 “Sunp 913 Yat pasreyd ssip ptig pamojjras aie sieyago pu tynottt ayy ttosy podvads are stuiad ayy jo autog ‘du paysnoo st ‘sued SIsojnoreqtiz jo SuOT]]IUL sureiuoD YoIyM pus ‘pascdutos ore AVYI YI Jo |BILaIVUL 9} UMOP YReIq SduN] sy} UI Se_MpouU snopnoseqny eo Surya Ig PUB SUIMAYJOS a1e IVY] SaTNpoU sNoTNoIsqny Wo, pua}xa yeyy soqng ALE yedoaes pure ‘491a¥0 snofno ‘sno1guinu smoys eingotd at, ON Ue “MOO B WOIZ SUN] SNO[NoIeqny ¥ Jo U0IWDEg— ‘OT * -Jaqn} ssIvp VUO ‘saynpou snoTNozeqn unor ApIvou T l 24 LIMITATIONS OF THE TEST. ; The test should not be applied to cows that have just calved or are about to calve, as the temperature at this time is apt to vary considerably from the normal. For the same reason it should not be applied to any animal that is in a feverish condition from any cause. : ; The test fails to detect the presence of the disease in the animal that is very recently infected. The disease has to make a little progress before the test reveals its presence, and in the beginning of each case there is a period between the entrance of the germs into the body and the time when they have multiplied sufficiently for the test to reveal their presence. This is called the period of incubation and lasts from ten days to two months. When the disease is far advanced and the animal is wasting, the test some- times fails to detect it. This is not of much practical importance as such cases can generally be recognized without the aid of tuberculin. PROTECTIVE INOCULATION. For some years efforts have been made to discover a method of rendering cattle immune to the disease in such a way as men are protected from smallpox by vaccination. Up to the present these efforts have been only partially success- ful, and until the methods in use have been perfected by further investigations, they cannot be recommended as of practical use in the suppression of the disease. SUPPRESSION OF THE DISEASE. The first step in getting rid of the disease is to find out how many of the herd are affected by it. This is done by applying the tuberculin test. This will show a larger or smaller number of the herd to be affected, and the proper course to pursue will depend largely upon the proportion of the reactors in it. Suppose that only a few cattle react, say fifteen out of a hundred, or in that proportion. In this case the reactors are first carefully examined and if any of them show symptoms of the disease by coughing, loss of condition or any other of the signs by which the disease is recognized without the test, such animals should be slaughtered. The other reactors should then be entirely separated from the healthy cattle. If possible they should be put in a separate building, but if this cannot be done, a tight partition should be built between the diseased and the healthy cattle, and separate ventilation provided. The person who attends to the reactors should not go near the healthy animals, as he may carry the infection to them on his hands, clothes or boots. For the same reason, the feeding and watering must be done with separate utensils. When at pasture, the reactors must not be put into a field where they can reach across a fence to healthy cattle. Whenever a calf is born among the reactors, it should be immediately separated from its mother and brought up by hand or on a healthy cow. The calf is usually born healthy, but would soon catch the disease from its mother if allowed to remain with her. 25 No. 11.—Sections of a tuberculous heart from a cow. The light parts are tuberculous. The heart muscle is greatly reduced in volume and is prevented from working properly by the tuber- culous material by which it is surrounded. The picture shows how badly an animal may become diseased with tuberculosis before it dies. One reason why tuberculosis is so common among persons and cattle is that many persons and cattle pass tuberculosis germs from their bodies before any one knows or suspects that they have tuberculosis and can give the disease to others. 26 The milk of reacting cows may be used if it is first boiled or heated to a point sufficient to kill the germs. This heating to a point less than boiling it is called Pasteurizing, and is safe provided all the milk reaches the required degree of heat and is kept there sufficiently long. For this it is necessary to keep the milk for twenty minutes at 149 degrees Fahrenheit or for five minutes at 176 degrees Iahrenheit. This system of dealing with tuberculosis in a herd was planned by Pro. fessor Bang, of Denmark, and has been very successfully followed in that country for some years. It has the advantage of allowing the reactors to by made use of while a sound herd is being built up. Under this system the sound herd increases in numbers as healthy calves are added to it, while the diseased lierd becomes smaller as the reactors die off or are killed as open cases of tuber- culosis. Finally a point is reached where only a few reactors remain and the owner will then find it to his interest to kill them rather than have the trouble of keeping them isolated. Some time is required for the successful carrying out of the Bang system, and the owner must be prepared to follow it steadily and faithfully for the whole time that is needed, which may be several years. During this time, the healthy herd must be tested every six months and any reactors removed to the diseased herd. At the same time, a sharp lookout must be kept for animals showing definite symptoms of the disease. These should be destroyed promptly as they are the most dangerous source of infection. DEALING WITH A BADLY INFECTED HERD. Where the test shows more than half the number diseased a somewhat different plan is required than the Bang system. This herd is so badly affected that the non-reactors cannot safely be considered healthy. Many of them are sure to have been infected with the disease quite recently, so that the test fails to detect it. These will react at the next test and in the meantime may develop the disease so rapidly as to infect others. This will repeat the difficulty ocenr- ring at the first test, and it would be a long and tedions process of weeding before even a small but perfectly healthy herd could be established. For these reasons it is better to treat such a herd as if it were entirely diseased, and to begin with the new-born calves to build up a healthy herd. The method from this point is exactly the same as the Bang system, except that as there are no healthy cows to act as foster mothers, the calves must be raised on pasteurized milk. At six months old, the calves are tested and reactors are transferred to the other herd. This plan was devised by a German veter- inary surgeon named Ostertag, and is known as the Ostertag system. It is very successful when carefully carried out. While getting rid of the disease by whatever system may he adopted, an animal should never be bought for the healthy herd unless known to be healthy. The tuberculin test should be applied, and if possible the animal should be selected from a herd that is known to be free from tuberenlosis. New pur- 27 No. 12.—Tuberculosis of the omentum or caul or the net covering the bowels. This form of tuberculosis is known as Pearl Disease, because the tuberculous tumours look like pearls. No. 13.—Tuberculosis of the oment form of Pearl Disease, in which each nodule is about the size of a large number of smaller nodules which have grown together. um or caul or the net covering the bowels. The picture shows another grape and is composed of a 29 chases should be isolated or kept apart from the healthy herd and, if possible, from each other for at least three months, when they should be re-tested to make sure they are healthy before putting them with other cattle. SANITATION. Dark, dirty, crowded stables are favourable to tuberculosis. Under these conditions the disease spreads rapidly and is only kept out with difficulty. Clean, airy, well-lighted stables on the other hand, are unfavourable to the development of the disease. If brought into such a stable, it does not spread so rapidly and is not so difficult to get rid of as in the first case. A well built, sanitary stable need not be made of expensive material or of elaborate design, but should have plenty of light, air and drainage. Light is very important. Direct sunlight is a great destroyer of germ life. Tubercle bacilli soon die if exposed to sunlight. It is a disinfectant always ready to work without cost. Sunlight is also necessary to the health of animals. Men deprived of it for any length of time, as prisoners in jail, ‘kecome pale and lose the appearance of health. Cattle that are constantly con- fined in dark stables become lowered in vitality and are ready to catch any disease with which they come in contact. For these reasons the cow stables should have plenty of windows on two or more sides if possible, so that the sunlight can reach every part of the interior some part of the day. Pure air is also very important. In badly ventilated stables, the air is breathed over and over again, until it becomes more or less poisonous. Animals kept in such conditions become gradually reduced in vitality. This change may not be noticeable to the observer, but becomes apparent if the animal is exposed to disease. It readily contracts disease and does not recover from it readily. . Stables should therefore have plenty of air space for each animal. This requires the ceiling to be high, the stalls roomy and the passages wide. In addition to this ample air space, some way of changing the air in a stable must be provided. This is done by suitable openings in the walls and roof and com- prises the system of ventilation. VENTILATION. Ventilation to be successful must provide for two things, first, the removal of the foul air from the inside and second, the bringing in of fresh air from outside the building. No system is good that fails to accomplish these objects, without causing unnecessary draughts. The usual way is to bring in fresh air through open windows, and in cold ° weather, through ventilating shafts, which may be concealed in the walls or beneath the floor. The foul air is removed by open windows and by ventilating ‘shafts from the ceiling to the roof, where they are usually protected by a hood. When both inlets and outlets are proportioned to the size of the building, there should be a constant circulation of air, and no sensation of closeness should be perceptible in the stable. 30 DRAINAGE. Drainage removes the liquid refuse from the stable by suitable gutters and drains. It cannot do this unless the floor is water-tight, and concrete flooring is therefore recommended. Urine leaking through cracks in the floor until the soil beneath is saturated is a frequent source of foul odours and unhealthy stables. CLEANLINESS. Since the manure of tuberculous cattle often contains living tubercle germs. in vast numbers, the importance of keeping it well cleaned out of the stable is readily seen. Such manure is not only dangerous to other cattle in the stable, but may be the means of conveying the disease to children. Often cows are seen with their flanks encrusted with dry dung. Parts often break off while the cow is milked and some of it is likely to fall into the milk pail. The larger lumps are strained out, but the smaller particles remain, and also the tubercle- germs which are small enough to pass through any strainer. These stay in the milk and make it a fruitful cause of the disease in the young. Stables should be cleaned out often and the manure put where it cannot: be picked over by hogs or cattle. These animals are easily infected in that way. Cleanliness also includes keeping the walls and ceilings free from dirt, dust: and cobwebs. These are all good resting places for disease germs. Whitewashing the interior of the stable at least twice a year is a great aid to cleanliness, end also has a distinct effect in destroying disease germs. In many municipalities, dairy stables are required to be whitewashed at regular intervals, and it is a practice that should be universal. MEMBERS OF THE INTERNATIONAL COMMISSION ON THE CONTROL OF BOVINE TUBERCULOSIS. J. G. Rutherford, C.M.G., V.S., H.A.R.C.V.S., Veterinary Director General and Live Stock Commissioner of the Dominion of Canada, Ottawa, Canada; Chairman. M. H. Reynolds, D.V.M., Professor of Veterinary Science, College of Agriculture and Experiment Station, University of Minnesota, St. Anthony Park, St. Paul, Minn.; Secretary. Hon. W. C. Edwards, Senator, Canadian Parliament, Ottawa, Canada. J. J. Ferguson, B.S.A., head of the Animal Foods Branch, Swift & Co., Chicago, Ill. J. W. Flavelle, LL.D., Governor, University of Toronto; President, William Davies Packing Co.; Toronto, Canada. Hon. W. D. Hoard, ex-Governor of Wisconsin; Editor of Hoard’s Dairyman,; Fort: Atkinson, Wis. Charles A. Hodgetts, M.D., C.M., L.R.C.P., Chief Medical Adviser, Commission on Conservation for Canada, Ottawa, Canada. J. N. Hurty, M.D., Secretary, State Board of Health of Indiana, Indianapolis, Ind. John R. Mohler, A.M., V.M.D., Chief of the Pathological Division, Bureau of Animal Industry, United States Department of Agriculture, Washington, D.C. Veranus A. Moore, B.S., M.D., Director of the New York State Veterinary College Cornell University, Ithaca, N.Y. Mazyck P. Ravenel, M.D., Professor of Bacteriology, University of Wisconsin, Madison, Wis. E. C. Schroeder, M.D.V., Superintendent of Experiment Station, Bureau of Animal Industry, United States Department of Agriculture, Bethesda, Md. T. W. Tomlinson, Secretary, American National Live Stock Association, Denver, Col. Frederick Torrance, B.A., D.V.S., Director of the Faculty of Comparative Medicine, University of Manitoba, Winnipeg, Canada. 31 :