?:, is Sf LIBRARY NEW YORK STATE VETERINARY COLLEGE ITHACA, N.Y. Cornell University Library SF 745.H67 V.I A system of veterinary medicine, 3 1924 000 012 868 Date Due Library Burcai Cat. No. 1137 The original of tiiis bool< is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924000012868 A SYSTEM OF VETERINARY MEDICINE " Together let us beat this ample field, Try what the open, what the covert yield. ' ' Pope. "Look to the essence of a thing, whether it be a point of doctrine, of practice, or of interpretation." Marcus Attkelius Antoninus : Meditations, viii. 22. A SYSTEM OF VETERINARY MEDICINE BY VARIOUS WRITERS EDITED BY E. WALLIS HOARE, F.R.C.V.S. LECTURER IN VETERINARY HYGIENE, UNIVERSITY COLLEGE, CORK LATE EXAMINER IN ANATOMY, ROYAL COLLEGE OF VETERINARY SURGEONS LATE EXTERNAL EXAMINER IN VETERINARY TOXICOLOGY, JURISPRUDENCE AND SANITARY LAW, UNIVERSITY OF LIVERPOOL AUTHOR OF "VETERINARY THERAPEUTICS AND PHARMACOLOGY" VOL. I MICROBIAL DISEASES 1 1 nil'/ 1'''^' ■'"'' . ; I r^ (; t. f: T CHICAGO ALEX. EGER 1913 .\.J 5F - !.,1 I TO WILLIAM HUNTING, F.R.C.V.S. AS A SLIGHT TRIBUTE TO HIS LABOURS IN THE CAUSE OF VETERINARY SCIENCE, HIS VALUABLE ADDITIONS TO VETERINARY LITERATURE, AND HIS SKILL AS A CLINICIAN, THIS WORK IS DEDICATED BY THE EDITOR PREFACE TO VOL. 1 To produce a work on veterinary medicine which fulfils the functions of a textbook for the student, and is likely to prove useful to the practi- tioner for reference, is by no means an easy task in the present day, for not only is the subject an extensive and progressive one, but also it includes the consideration of many diseases which, in former times, owing to a limited knowledge of their etiology, pathology, and diagnosis, could only be discussed within narrow limits. But at the present time, in consequence of the researches of the pathologist, combined with the observations of the chnician, these diseases have been so thoroughly investigated that each requires to be dealt with by an author who has devoted special attention to individual subjects, and has had consider- able clinical experience in dealing with the various phases that are pre- sented in the affection he undertakes to describe. In fact, it can truly be said that no individual, even though he pos- sessed the widest experience of dise^ases in animals and had unlimited time at his disposal, could, unaided, either compile or write a work on veterinary medicine so as to do anything like justice to the subject. Moreover, of late years the sphere of utility of the practitioner has been widely extended, and while formerly a Jinowledge of the diseases of horses and cattle was regarded as suf&cient for the purposes of his calhng, it is now essential that he should be acquainted with the ailments of the smaller animals, and also be proficient in the subject of preventive medicine and in public health duties. It was after due consideration of the above facts that, acting on the suggestion of some professional friends, the present work was undertaken by the Editor. By securing the collaboration of a number of eminent British veterinarians, he has attempted to produce a work which, he ventures to hope, may prove useful to both practitioners and students of veterinary medicine in all English-speaking countries. : It may be considered by some that the subjects are treated rather too fully for the purposes of a textbook for students, but the day is past viii PREFACE TO VOL. I when a series of cut-and-dried facts concerning each disease sufficed for the needs of the student. It is necessary that he should be acquainted with the various phases presented by each afEection, and with its atj^ieal as well as its typical characteristics. The function of a textbook is to act as a guide to the clinical study and observation of disease, but, in addition to this, it should stimulate the student to think for himself, and to note every detail in connection with a case. To commit to memory a series of epigrammatic statements referring to etiology, symptoms., diagnosis, and treatment, is of little value to the student of veterinary medicine, as it leads him to the erroneous beUef that every disease possesses a stereotyped hst of symptoms, presents a characteristic chnical picture, and should be treated by hard-and-fast therapeutical rules. The Editor does not consider that any apology is necessary for the amount of space devoted to diseases other than those of horses and cattle. The importance of canine and feUne medicine in the present day has rendered such a course desirable and essential. Similar remarks apply to the articles on avian diseases, and the microbial affections of fish, etc. There was a time when such subjects were regarded as belonging to the sphere of the kennel-man, the gamekeeper, the empiric, and the patent-medicine vendor ; but dog-fanciers and sportsmen are now beginning to appreciate the fact that the veterinary practitioner, by his scientific training, is the proper person to advise on all matters of this kind. Hence a modern work on veterinary medicine should supply full information on these subjects, so that a general practitioner may be enabled to refer to it with advantage when he is called on to investigate diseases which are outside the sphere of his ordinary practice. In consequence of the rapid progress of veterinary medicine in America and in the Colonies, it has been deemed advisable to devote attention to diseases occurring in these countries. Tropical diseases are fully considered by speciaUsts in the subject, and it is hoped that the work will prove of value to practitioners in India and Africa. The present volume is devoted to microbial diseases, as it seems desirable to class these affections together. In Volume II. the diseases of the various organs will receive consideration. To all the collaborators the Editor begs to offer his sincere thanks. They have readily responded to his call for assistance, and, although busily engaged in professional duties, with increasing demands on their time, they have spared no efforts to render the work as useful as possible. A large share of the task has fallen to Mr. Henry Gray, who has not only written on the subjects on which he has speciahsed, but also has PREFACE TO VOL. 1 ix read the proof-sheets as they passed through the press, and suggested many useful alterations and additions. His wide experience of canine medicine has enabled him to write authoritatively on this subject, and the sections on Canine Distemper, Canine Typhus, and other microbial affections of the dog, cannot but prove of marked value to practitioners interested in the diseases of this a|&mal. To Professor J. F. Craig, Royal Veterinary College of Ireland, the Editor is also deeply indebted for much assistance, many useful sug- « gestions, and kind encouragement ; also for writing the introduction to the section on Piroplasmosis, and arranging the subjects therein. To Mr. W. Jackson Young, F.R.C.V.S., D.V.S,M., he is indebted for many valuable suggestions in connection with several of the sections. The onerous task of preparing the index has been carried out by Mrs. Hoare with care and ability. To all those professional friends who by their advice and encourage- ment helped in the preparation of the work the Editor desires to express his thanks, and to acknowledge their valuable assistance. In the preparation of a work of this kind it was necessary to consult freely the various professional journals, and the Editor gladly acknow- ledges the large amount of information derived from the Veterina/ry Record, the Veterinary News, the Veterina/ry Jov/rnal, the Journal of Comparative Pathology and Therapeutics, and the American Journal of Veterinary Medicine. For errors of omission and commission the Editor craves the indulgence of his readers. He is fully aware of the magnitude of the task he has undertaken, and the difficulties to be overcome. To those who expect perfection in a work of the kind he would point out that, being engaged in the daily duties of a general practitioner, he has not been able to devote as much time and energy as he would desire to the preparation of the sections for which he is responsible and to the editing of the entire material ; and if, in this attempt to make a useful addition to existing veterinary hteratuie, he has only succeeded in lajdng the foundation on which some abler hand may in the future erect a structure destined to be a reflex of current knowledge in veterinary medicine, he will feel that his labour has not been in vain. E. W. H. 18, Cook Steeet, Cork. Fehrucury, 1913. CONTENTS OF VOL. I 1 59 105 7 Mamgnant (Edema . j2 ASTHBAX . . _ 21 BtACK-QxTARTEB . . . Ar GliAUDBES TiTBEBOULOSIS Johne's Disease . jgg PSBUDO-TXTBEBCTTLOSIS . . . 204 STBBPTOBAcnJiARY Psettdo-Tttbebculosis - - . 217 Ulcerous Lymphangitis in the Horse . . . 220 CoNTAGioirs Acne 224 Tetanits - . . . . 227 Erysipelas - . , . . 249 Actinomycosis - -' ... 257 ACTINOBAdLLOSIS . ... 269 BoviNB Farcy - . 271 Strbptotheicic Psbddo-Tubbbctjlosis IN the Hobse - - 274 Botbiomycosis - - . 275 Bacellaby Nboeosis - - - 282 eONTAQIOXJS PUSTTJLAE DERMATITIS OF ShEBP - 300 Relationship between Human Diphthebia and Cebtain Diseases op Animals .... 310 I. Diphtheria in the Cat . 317 n. Avian Diphtheria . 319 III. Efithbuoma Contagiosum - - 323 Epizootic Abortion - - - 325 ■ Contagious Gbanttlab Vaginitis op Cattle - 348 Gangrenous Vaginitis in Cattle - - . 356 Vesioulab Exanthema of Hobsbs and Cattle - - 359 Venbbeal Disease in Sheep - - ... 364 Venereal Diseases in the Dog, Rabbit, Habe, and Fowl - - 366 xi xii COIJTENTS Of VOL. 1 Hot I EpizoStic Infectiotts Epididymitis in the Hoese - ' - 372 Mammitis - ... - 374 CoNTAGiors Agalaxia - - - - 404 The H^moebhagic Septicemias ... - 407 CoBNSTAUc Disease - - - 416 Avian Cholera and Othee Infectious Diseases of Bieds, etc. - 420 Septic Pneumonia of Calves and Lambs - 496 White Scoue - - - 501 JoiNT-Iix - 509 . Bacillaby Pyblonephkitis in Cattle - 523 Malignant Cataeehal Eevee of Bovines - 529 LiQNiJiBEs' Malignant CEdema of Oxen 534 SwiNB Fbveb - 538 Swine Plague - - - - 530 Swine Ebysipelas - - 551 Contagious Bovine Plbubo-Pneumonia - 569 Vaeiola - - - 570 Contagious Pustulab Stomatitis ... 596 Rabies - - - - 599 I. Contagious Pseudo-Rabies r - • - - 630 II. Infectious Bulbae Paealysis - - 632 Canine Distempee .....--- 635 Distempeb in the Cat and Othee Animals - 720 Canine Typhus ob Contagious Gasteo-Entbbitis - - - 735 I. Feline Typhus oe EpizoStic Gasteo-Entebitis of the Cat - 760 II. Epizootic Enteeitis in the Cat - - 761 Foot and Mouth Disease - .... 764 Strangles - - - - 790 Immunisation and Vaccine Theeapy as applied to Strangles - 822 Contagious Pneumonia of the Hoese - 825 Influenza - - . . - 843 Purpura Hemorrhagica - - - - - 869 Epizootic Cerbbeo-Spinal Meningitis - - 889 Infectious Paraplegia - - - - 900 Mediteeeanean Fbvbr ... . . 902 Rinderpest ... ..... 916 Equine Pebnicious Anemia ..... 927 Milk-Sickness - - - - 938 Dengue - - ...... 941 Bacteeial Diseases of Fish - .... 946 The Quail Disease ... - . 972 Choleeaio Gasteo-Entbeitis in Birds - - - 975 CONTENTS OF VOL. I xiii PAGE FmoFLASMOSis ...... g7g I. Bovine PiBotLASMOsis . ' - . . -981 A. Texas Fever j . . . . 933 B. East Coast Fever - .... 994 C. ArtMBNTS DUB TO PiROFLASMA MOTANS . - - 1005 D. British Redwater . - 1006 II. OVINB PiROPLASMOSIS (CaRCEAQ) 1013 in. EQimrE PmoPLASMosis - . 1015 rV. CaNINB PraOFLASMOSIS - 1029 Gall-Siokness or Cattle . ... i034 Trypanosomes and Trypanosomiasis .... 1039 I. Mal de Caderas ...... 1061 n. Nagana . 1063 m. DOTJRINE . - - 1067 IV. Surra 1081 V. Trypanosomiasis of Birds and Pishes - - 1113 Some Protozoal Diseases of Birds, Fishes, etc. - - 1118 Lbisemaniasis in the Dog - ... 116I The CoccaBiA ... ... 1164 Aspergillosis - . ...... 12O6 Blastomycosis in the Goose ..... 1223 Spirocblsitosis - ....... 1224 Braxy - . .... 1244 l0ufing.ill . . ... . 1251 Hbartwatbr . - - . ., 1258 Blue Tongue . .... 1269 South African Horsb.Sickness - ... 1280 Epizootic Lymphangitis ... ... 1289 Appendix ... ■ 1302 Jndbx - ' '' ■■ ' ' ' ' " 1319 LIST OF CONTRIBUTORS TO VOL. I ANONYMOUS. Black-Quaxtei. White Scour. Swine Fever. Swine Plague. Swine Erysipelas. BALDRBY, MAJOR, F.S.H., F.R.C.V.S., D.V.H., I.C.V.D. Equine Piroplasmosis. Dourine. BEGG, HUGH, F.R.C.V.S. Manuuitis. CRAIG, J. F., M.A., M.R.C.V.S. Contagions Bovine Pleuro-Pneumonia. British Redwater. Ovine Piro> plasmosis. CROSS, H. B., M.R.C.V.S., D.V.H. ^ Rinderpest. GOPTON, A., F.R.C.V.S. Bacillary Necrosis. Relationship between Human Diphtheria and Certain Diseases of Animals. Avian Diphtheria. Epithelioma Contagiosum. Malignant Catarrhal Fever of Bovines. GRAVBS, T. CHIVBRS, M.B., B.S., B.Sc, M.R.C.S., L.R.C.P., M.R.C.V.S. Mediterranean Fever. GRAY, HENRY, M.R.C.V.S. Tuberculosis in the Dog and Cat. Pseudo-Tuberculosis in the Calf. Strep- tobacillary Pseudo-Tuberculosis. Ulcerous Lymphangitis in the Horse Actinobacillosis. Bovine Farcy. Streptothricic Pseudo-Tuberculosis in the Horse. Badllary Necrosis in the Horse, Dog, and Rabbit. Diphtheria in the Cat. Venereal Diseases in the Dog, Rabbit, etc. Epizootic Infec- tious Epididymitis in the Horse. Contagious Agalaxia. Some Infectious Diseases of Birds, etc. Lignieres' Malignant (Edema. Goat-Pox, Swine-Pox, etc. Canine Distemper. Canine Typhus. Influenza in the Dog and Cat. Bacterial Diseases of Fish. Quail Disease. Choleraic Gastro-Enteritis in Birds. Trypanosomiasis of Birds and Fishes. Some Protozoal Diseases of Birds, Fishes, etc. Leishmaniasis in the Dog. The Coccidia. Aspergillosis. Blastomycosis in the Goose. Spirochsetosis. HOARB, B. WALLIS, F.R.C.V.S. Tuberculosis. Pseudo-Tuberculosis. Contagious Acne. Tetanus. Ery- sipelas. Contagious Pustular Dermatitis of Sheep. Gangrenous Vaginitis in Cattle. Vesicular Exanthema of Horses and Cattle. Venereal Disease in Sheep. Hsemorrhagic Septicaemias. Septic Pneumonia in Calves. Joint-Ill. Bacillary Pyelonephritis in Cattle. Variola. Contagious Pustular Stoma- titis. Foot and Mouth Disease. Strangles. Contagions Pneumonia of tie Horse. Influenza in the Horse. Purpura Hsemorrhagica. Epizootic Cerebro-Spinal Meningitis. Equine Pernicious Anaemia. Milk-Sickness. Dengue. xvi LIST OF OONTEIBUTORS TO VOL. I HUGHES, H. TUDOR, B.Sc, M.B.C.V.S. Septiceemia. Fysemia. Malignant (Edema. HUGHES, R., F.R.C.V.S. JoinirHl. HUNTING, WILLIAM, F.R.C.V.S. Glandeis. INGRAM, G. L., M.R.C.V.S. Avian Tuberculosis. Pseudo-Tuberculosis. Hemorrhagic Septicsemias. LLOYD, J. S., F.R.C.V.S., D.V.S.M. Tuberculosis. MELLON, B. HARVEY, M.R.C.V.S. Braxy. Louping-Ill. MONTGOMERY, R. EUSTACE, M.R.C.V.S. Canine Firoplasmosis. Gall-Sickness of Cattle. Trypanosomes and Try- panosomiasis. Mai de Caderas. Nagana. OLVER, CAPTAIN A., F.R.C.V.S., A.V.C. Epizootic Lymphai^tis. PEASE. COLONEL H. T., M.R.C.V.S., LC.V.D Surra. REEKS, H. CAULTON, F.R.C.V.S. Anthrax. SPREULL, J„ P.R.C.V.S. Heartwater. Blue-Tongue. TODD, MAJOR A. G., M.R.O.V.S., A.V.C. Immunisation and Vaccine Therapy as applied to Strangles. WATKINS-iTECHFORD, LIEUTENANT -COLONEL H., F.R.C.V.S., F.R.S.E. South African Horse-Sickness. WEBB, CAPTAIN E. CLIVE, F.R.C.V.S., A.V.C. Rabies. "^ WILSON, AINSWORTH, F.R.C.V.S. Epizootic Abortion in Cattle. Contagious Granular Vaginitis of Cattle. WOOLDRIDGE, G. H., F.R.C.V.S., M.R.LA. Johne's Disease. Actinomycosis. Botriomycosis. WOOLLATT, S. B., F.R.C.V.S, Bovine Firoplasmosis. SYSTEM OF VETERINARY MEDICINE SEPTICEMIA By H. TUDOR HUGHES, B.Sc, M.R.C.V.S., Oswestry. Synonyms. — Septic infection ; Bactersemia ; Bacterial septicaemia. French : Septicemie. German : Septicamie ; Septichamie. GENERAL REMARKS. In the first place, we may point out that there is no one particular organism specific to this condition or to pyaemia ; various organisms may produce them, an(i more than one organism may be present at the same time. Also, the same organism may produce varying results under different circumstances — e.g., a local abscess, multiple abscesses, or a general septicaemia. The result will depend upon the degree of virulence of the organism, the path of infection, and the age, species, and degree of resistance of the animal. Septicemia is the term applied to a bacterial infection in which the main seat of multipKcation is the blood. Symptoms of general poisoning arise, but without the production of abscesses in the internal organs. In all cases oi septicaemia the organisms are more numerous in the capillaries of the internal organs than in the peripheral circulation, and thus it may not always be possible to detect any in the blood during life. . In a surgical sense, the term " septicaemia " was formerly apphed to a condition in which the blood and tissues of the body were invaded by pyogenic organisms ; but in the present day the term is appKed in a medical sense to any condition in which microbic invasion of the blood and tissues occurs, with or without a local site of infection, and without metastatic foci of suppuration. VOL. I. 1 2 SYSTEM OF VETERINARY MEDICINE BACTERIOLOGY. The organisms most commonly responsible for this condition are the Streptococcus pyogenes and the Staphylococcus pyogenes aureus. Less common causes are the Staphylococcus pyogenes albus and the Bacillus coli. 1. Streptococcus Pyogenes. — This organism is a facultative para- site having a ubiquitous distribution. Microscopical Characters. — The individual cocci are about 1 > in diameter, ai;d arranged in linear series, forming chains of varying length, comparable to chains of beads. When rapid multiplication is in progressj the chain frequently appears as if it were made up of diplococci. In old cultures many of the cocci appear swollen up to twice the usual size, and are regarded as involution forms. It is non- motile. Staining. — It stains by any of the basic aniline dyes, and also by the methods of Gram and Claudius. Ctdtivation. — It grows rapidly at room temperature, but much more rapidly at body temperature. In gelatine a stab culture becomes visible about the second day as a thin whitish line, formed of minute rounded colonies. The growth does not spread on the surface, and the gelatine is not hquefied. On agar it forms very small translucent colonies. On potato there is no visible growth. In bouillon the growth is almost entirely at the bottom, whitish, somewhat flufiy in appearance, and easily broken up by shaking. 2. Staphylococcus Pyogenes Axjeeus. — Like the Streptococcus pyogenes, this is a facultative parasite with a ubiquitous distribution. Microscopical Characters. — In size the individual cocci are just a Httle less than 1 /u, (about 0-9 /^) in diameter. Growth takes place irregularly, so that the colonies have the appearance of irregular masses like bunches of grapes. It is non-motile. Staiming. — It stains readily with any of the basic aniline dyes, and also by the methods of Gram and Claudius. Cultivation. — It grows readily at low summer temperatures, but much more rapidly at body temperature, and in or on all the common media. In gelatine a stab culture is visible as a streak along the whole needle- track within two days, and almost immediately liquefaction begins, starting at the top, and forming a funnel-shaped pool of liquid gelatine, turbid from suspended cocci. Liquefaction rapidly spreads throughout the whole of the medium, and the grovrth settles to the bottom as a bright yellow flocculent deposit. Liquefaction is due to a tryptic ferment elaborated by the cocci. On agar incubated at 37° C. a stroke culture is visible in twenty-four hours as a smooth, shining, yellowish line, which SEPTICEMIA 3 spreads over the surface and becomes bright orange in colour, resembling a streak of oil-paint. On potato it grows well, with a golden or orange yellow colour. In bouillon it produces a uniform turbidity; which eventually settles to the bottom as a brownish-yellow layer. 3. Staphylococcus Pyogenes Aibus. — This organism is similar in character to the foregoing, except that its growth on all the media is white. SYMPTOMS. Septicaemia most commonly follows upon a local infection — e.g., a wound, or a septic condition of the womb. At first the toxins alone are absorbed into the blood, the condition at this stage being designated a toxaemia, in contradistinction to the later stage, when the organisms are themselves present in the blood, the condition being then known as a septicaemia or a bacteraemia. When the toxins of putrefactive organisms are being absorbed into the blood, the condition is known as saprsemia (see p. 5). The symptoms are those of fever, sometimes ushered in by an attack of rigors. The temperature rises to 106° or 107° F., and remains high, with but slight remissions and no intermissions. In some cases there is no great hyperthermia, but these are the exception, The pulse is frequent, quick, and feeble, and the heart-sounds are weak. Indications of general disturbance are present, there is complete loss of appetite, great debility and dulness, muscular tremors, and occasionally paralysis of the hind-quarters. The mucous membranes are dirty red, or may show icteric discoloration and ecchymoses. The urine is dis- coloured and albuminous. Towards the end there is continued diarrhoea, which may be blood-stained and accompanied by colicky pains. As death approaches dyspnoea comes on, whilst the temperature may be extremely high ; sometimes the temperature is subnormal, and this, with a very rapid pulse, is always a grave indication. The disease usually takes a few days to run its course, and recoveries are rare. MORBID ANATOMY. Decomposition sets in early, rigor mortis is feeble, and the tissues have a dark and livid appearance. The blood coagulates imperfectly, and is dark and tarry in colour ; if allowed to stand, the serum which separates from the corpuscles is much stained from the breaking up of the red blood-corpuscles, which results from the action of the toxins. The endocardium and tunica intima of the larger vessels are stained dark purple or black. Most of the serous cavities contain a certain amount of blood-stained fluid, and most of the serous membranes bear well- 4 SYSTEM OF VETEEINARY MEDICINE marked petecMae, especially under the pericardium and pleura. The lungs are deeply congested ; the liver, spleen, and kidneys are enlarged, softened, and congested, particularly the spleen. On microscopical examination bacteria are usually demonstrable in the blood and internal organs, especially in the spleen. DIAGNOSIS. Septicaemia is distinguished from pyaemia by the absence of repeated rigors and secondary abscesses, and by a more regular and continuous type of fever. Saprsemia is always associated with an obvious focus of putrefaction, whilst septicaemia may occur with little local manifestation. Septic traumatic fever may be so severe as to give one the idea that septicaemia is setting in ; but if only the former condition is present, it rapidly disappears on freely opening up and draining the wound. PROGNOSIS. The prognosis of septicaemia is always very grave, recoveries being quite exceptional. TREATMENT. Prophylactic measures against septicaemia consist in the thorough appHcation of aseptic and antiseptic measures. Suppurating wounds, gangrenous centres, fistulse, sinuses, and sloughing injuries, where dis- charges may become putrid, should be frequently cleansed with disinfec- tant solutions. If pus accumulates in a wound on account of the disposi. tion and direction of the latter, a counter-opening should be made and drainage effected. Septicaemia and septic intoxications of uterine origin are prevented by antiseptic irrigations of the uterus, after detaching and removing the foetal membranes, if these have not been expelled. Curative treatment comprises attention to any local lesions, as well as internal medication. Any local centre of inflammation should first of all be dealt with ; the part should be irrigated with or bathed in a strong antiseptic solution, or thoroughly soaked with hydrogen peroxide solu- tion, and then dusted over with an antiseptic dry dressing. In some cases free incisions, evacuation of pus and putrid discharges, and provision for drainage may be necessary. In cases of puerperal septicaemia the uterus should be irrigated at once with a disinfectant solution, which will need to be repeated once or twice a day. The best agents for disinfecting the womb are : lysol, 1 in 100 ; creolin, 1 or 2 in 100 ; chinosol, 1 in 500 to 1 in 1,000 ; hydrogen peroxide, SBPTIOJIMIA 5 5 to 10 vola. per cent. After washing out the womb, it is a good plan to introduce an antiseptic pessary, which may be made up of chinosol, salol, boric acid, iodoform, or a combination of these, either in gelatine or cacao butter. In this way the uterus is rendered antiseptic for the time between the irrigations, and it is not necessary to irrigate so frequently. Often it is impossible to apply surgical treatment in time, as infection of the blood has taken place already. When the streptococcus is responsible for the trouble, as is most frequently the case, the polyvalent antistreptococcic serum may be tried. Another method of treatment that has been put forward is the intra- venous injection of large quantities of normal saline solution repeated two or three times a day ; diuresis and diarrhoea are induced, and it is hoped that by this means the organisms and their products may be eliminated. This treatment is likely to give better results in cases of saprsemia than in cases of septicsemia. If the intravenous injections of normal saline solution cannot be carried out, subcutaneous injections of a similar solution or saline enemata, repeated two or three times a day, may be adopted instead. Internal antiseptics may also be administered, such as carbohc acid, or large doses of solution of acetozone (1 to 1,000), but their value is doubtful. It is important that the patient should be placed in hygienic surround- ings and made comfortable ; his mouth and nostrils should be sponged, plenty of suitable and easily digested food given, and everything possible done to coax him to feed. Tonics and stimulants are the medicinal agents indicated. It is difficult to control the fever, and quinine is probably better than antifebrin or antipyrin for this purpose. SAPRSIMIA. Sapraemia is also known as septic intoxication. It arises from the absorption of toxins of putrefactive bacteria into the blood, and is essentially a toxaemia. It differs from septicaemia in the following resipects : In sapraemia micro-organisms are not present in the blood, and the blood is not infective — i.e., if a small amount be inoculated into another animal, the disease is not reproduced. In septicsemia the blood is infective, it contains micro-organisms, and if a minute amount taken even at a distance from the local focus be inoculated into another animal, the disease is transmitted thereto. 6 SYSTEM OF VETERIlfARY MEDICINE Saprsemia results from the presence of a mass of putrefying tissue or a collection of putrid fluid in the body, from which absorption of toxins may occur. Examples are found in retention of a decomposing placenta, punctured wounds accompanied by putrid suppuration of the underlying tissue, septic pneumonia, the presence of a putrefjdng blood-clot in the pleural or peritoneal cavity resulting from a wound, etc. It must be remembered that a clinical distinction between sapraemia and septicaemia is not always possible ; the former may lead on to the latter, or both may be combined. The symptoms of saprsemia depend on the amount of the toxins absorbed. Rigors are observed, followed by a continuous high tempera- ture, the constitutional symptoms being in proportion to the severity of the case. The toxins in some instances act chiefly on the alimentary canal, causing diarrhoea and evidences of gastro-enteritis ; in others the nervous system is acted on, marked prostration and a comatose condition re- sulting. The lesions resemble those described as occurring in septicsemia. Saprsemia tends to recovery if treatment be adopted early. Treatment is to be carried out on similar lines to those advised for septicaemia. PY.EMIA By H. TUDOR HUGHES, B.So., M.R.C.V.S.4 Oswestry. Synonyms. — Septico-pysemia. French : Pyemie. German : Pyamie. Pyaemia is a condition the essential feature in which is the production of multiple abscesses in various parts of the body, the result of metastasis. It is not of such frequent occurrence as septicaemia. Metastasis may occur by Way of the lymphatics, in which case the glands are usually involved, or by way of the bloodvessels. In the latter case a few organisms may gain entrance into the blood from a local lesion, and settle in a favourable part or in a damaged tissue ; or a septic phlebitis may take place, with suppurative softening of the thrombus and resulting embolism ; or there may be direct extension along a vein, producing spreading thrombosis and suppuration within the vein. In suppuration the two main features are — 1. The immigration of leucocytes — chiefly polymorphonuclear — owing io the positive chemotaxis or attraction exerted by the bacteria and their toxins. 2. The liquefaction of the histological elements of the affected tissue, with necrosis of the cells of the part. The result is the replacement of the affected tissue by a creamy fluid called "pus," which varies in character according to the variety and virulence of the bacteria present. The Bacteriology is the same as that described under Septicaemia, the Streptococcus pyogenes and the Staphylococcus pyogenes aureus being the causal organisms most frequently met with. When these organisms are of an exalted degree of virulence, they bring about septicaemia, and when of a lesser degree of virulence, pyaemia. The cause of pyaemia may be said to be any condition which leads to the formation and detachment of infective emboli in the circulation ; 7 8 SYSTEM OF VETERINARY MEDICINE the commonest conditions occur in the veins from disintegration of a thrombus. Acute infective inflammation of the cancellous tissue of bones is most to be feared, owing to the veins being abundant, thin- walled, and under pressure, on account of the bone being hard and unyield- ing. When an infective embolus becomes jammed in any of the smaller vessels, a thrombus is formed, in which the bacteria rapidly multiply, and pass through the vessel wall into the surrounding tissues, setting up localised inflammation, followed by suppuration and abscess formation. The lungs, being the first filter for emboli in the systemic circulation, are usually affected first, and infarction is brought about when the emboli have lodged in a terminal artery, the infarct being at first red, and then greyish-yellow when the formation of pus has taken place. When the thrombi in the lungs start to disintegrate, and infective emboli are carried through the heart into the systemic circulation, abscesses may follow in any part of the body, the most usual regions being the kidneys, spleen, liver, and joints. If the emboli are large in number and the symptoms severe, the condition is known as acute pycemia. Sometimes along with the pysamia there is development of the bacteria in the blood, constituting septico- pycemia. If the emboli are few and the symptoms less severe, the disease is known as chronic pycBmia. Conversely to malignant oedema, which is an early complication of wounds, pyaemia is a complication occurring at a later stage, though it may be no less formidable. Purulent infection may show itself at any time during the course of deep irregular wounds which suppurate profusely, in the course of fistulas following upon necrosis of the aponeuroses, tendons, or bones, and in the course of purulent inflammation of the synovial membranes, veins, or lymphatic trunks. In the Horse, phlebitis of the jugular vein, diseases of the poll, neck, and withers, quittor, purulent inflammations of the joints and tendon- sheaths, gangrene of the keratogenous membrane, and caries of the os pedis, are the affections most commonly associated with pyasmia. We may also include the irregular form of strangles as an affection in which pysemia is not uncommonly met with. In Cattle pysemia is most commonly seen as a complication of con- tused suppurating wounds and gangrenous or necrotic lesions, and the same applies to the smaller ruminants. In the Dog the usual causes are compound fractures, contusions, and other serious traumatic injuries of the Umbs. In the females of the different species puerperal pyaemias are met with. PYAEMIA 9 In young subjects, particularly foals and calves, purulent infection is frequently determined by a suppurative infection of the umbilical vein — "navel ill." The etiology of pyaemia may be summed up as depending on the existence of a suppurating injury or focus. Various conditions inherent to this injury, such as the vital resistance of the animal and the means of injury, favour its development. The principal are — ^the depth of the wound, the irregularities and crevices with which its walls are riddled, sloughs in which pus becomes stagnant, the poor general condition and exhaustion of the injured subject, and the insanitary surroundings in which animals are so often kept. The method of infection is often complex. In purulent phlebitis the intravenous clot, infected by pyogenic bacteria, detaches infective emboli, which are carried by the blood into the lungs and other organs. In the walls of fistulse, caused and kept going by necrosis {e.g., poll-evil, fistulous withers, and quittor), multiple phlebitis and lymphangitis are present, from which infection may arise. In old suppurating wounds, unaccompanied by phlebitis, the layer of granulations may be broken, and the blood and lymph streams thereby exposed to infection. SYMPTOMS. The onset of acute pyaemia is generally marked by the appearance of rigors, which may be repeated, and along with this a sudden rise in temperature occurs. The animal is dull and depressed, without appetite, but thirsty, and the excretions are diminished. The pulse becomes soft and weak. Patchy sweating is commonly seen. In connection with the wound there is from the commencement a change in the character of the suppuration. This is always considerably checked, and the pus which issues from the wound is of an unhealthy liquid nature, greyish or blood-stained, and full of cellular debris and microbes. The granulations are purple and friable; later they are sloughed off, and the product of their destruction forms a sanious and infectious liquid in the wound. There is no swelling of the borders of the wound, as in traumatic gtogrene. As the disease progresses, the general symptoms become more serious. There is rapid wasting and exhaustion of strength. The coat is staring, and the hair of the mane and tail is easily pulled out ; the ears and the extremities are cold. Secondary abscesses appear, and the symptoms which reveal their localisation— whether in the lungs, liver, kidneys, or brain, or purulent 10 SYSTEM OF VETERINAEY MEDICINE inflammation of the joints, synovial cavities, or pleura — are observed. There is often a greyish or sanguineous purulent discharge from the nostrils, with a foetid odour. Auscultation and percussion serve to dis- close the lesions in the lungs. The temperature undergoes considerable and rapid fluctuations. A profuse diarrhoea generally sets in, and leads to rapid weakening and exhaustion. In some cases there appear in various superficial parts phlegmonous swellings, which rapidly develop into abscesses. In strangles pyaemia there are often multiple abscesses of the lymphatic glands. The course of pyaemia is generally slower than that of traumatic gan- grene. According to the localisation and number of the secondary ab- scesses, the duration of the disease varies from a few days to several weeks. _ Pyaemia is considered less grave than septicaemia, but the generalised forms with numerous centres in the viscera are invariably fatal. Even when the causal organisms have only an attenuated virulence, or have been destroyed after becoming fixed in the organs, they kill by the visceral lesions thus set up. In Cows puerperal pyaemia is chiefly characterised by arthritis of the knee, hock, and stifle joints, tendo-synovitis of the flexors, perimetritis, and progressive wasting. TREATMENT. Prophylaxis consists in the application of the usual antiseptic measures. In the case of extensive, deep, and irregular wounds, it is important to prevent the accumulation of pus. Frequent cleansing with antiseptics and continuous irrigation are the best preventive means. It is often necessary to scarify, make counter-openings, and insert drainage- tubes, although as a general rule one should avoid injuring the granulation tissue ; but if the case is urgent, it must be done. For this purpose the thermo-cautery judiciously used is better than the knife, as the eschar remains adherent to the subjacent tissues until they are covered with granulations, which are not so liable to infection as are raw surfaces. Irrigations with hydrogen peroxide, strong antiseptic solutions, and the carbolic and sublimate spray, are useful. For injuries to the limbs warm antiseptic baths continued for twenty minutes or half an hour, and followed by moist dressings, are best, though dry dressings covered with absorbent materials are preferred by some. When indications of pyaemia set in, the wound must be rigorously and thoroughly cleansed, the cavities mopped out with hydrogen peroxide (10 vols, per cent.), or with a strong disinfectant solution (chloride of zinc, 5 to 7 per cent. ; carbolic acid, 5 per cent. ; or biniodide or sublimate, PYEMIA 11 1 in 500 to 1 in 1,000) and then powdered with iodoform, or placed under continuous cold-water irrigation. If any excessive or fungous granulations are present in the wound, they are best destroyed by the thermo-cautery. It must be recognised that one cannot render the wound aseptic, but it should be cleansed and disinfected as thoroughly as possible. If super- ficial collections of pus appear, they should be opened early, Internal treatment consists in the administration of agents capable of sustaining the animal's strength, checking the multiplication of the bacteria, and neutralising the effects of their toxins. Amongst the' drugs most generally used are alcohol, cafiein, quinine, nux vomica, strych- nine, carbolic acid and creolin. Most of these can be absorbed from the alimentary canal, and may be given by the mouth or by the rectum ; others, such as caffein and strychnine, can be given hypodermically. It is better to introduce the necessary remedies fer rectum than to forcibly ad- minister them by the mouth, as the latter course greatly upsets the patient- Treatment has been attempted by injecting antiseptics directly, into the circulation — solutions of carbolic acid, sublimate, or iodine, into the jugular vein two or three times daily. It is diflGlcult to believe that these agents could in this, or any other way, be introduced into the blood in a sufficient degree of concentration to destroy the bacteria without irre- parably and disastrously damaging the system in general. In those cases due to streptococci, antistreptococcic serum should be administered early, and repeated at proper intervals. Nursing is all-important, ^nd a liberal diet of light, tempting, and easily digested foods should be prescribed. In acute pyaemia, as in septicaemia, when the infecting organism has firmly established itself, it usually carries the day, in spite of all one can do and whatever antiseptics one may choose. As proof of the possibility of recovery from pyaemia, cases in horses are cited which, on post-mortem examination at a later date, revealed caseous purulent foci in the internal organs ; but on closer examination these have turned out to be cases of tuberculosis or glanders, and not pyaemia. Cadiot and Almy have had several cases of pyaemia in horses under treatment, but have not observed a recovery once clinical indications of secondary abscesses in the internal organs have presented themselves. In cases of chronic pyaemia, where the sequence of events is much slower, the preparation of a vaccine from the particular strain of organism, with which the animal is infected may be tried. In undertaking this little- tried method, one should proceed cautiously, and not introduce the vaccine in excessive doses, nor too frequently, until some more practicable method of control than the observation of the opsonic index is available. MALIGNANT CEDEMA By H. TUDOR HUGHES, B.So., M.R.C.V.S., Oswestry. Synonyms. — Traumatic spreading gangrene ; Hospital gangrene. Frmch : Septic^mie gangreneuse ; (Ed^me malin ; Gangrene trau- matiqne ; Gangrene gaseuse. German : Malignes (Edem Gangran. Definition. — ^Malignant oedema is a virulent inoculable disease occur- ring in man and- several species of animals, and due to the invasion of the tissues by the mahgnant oedema bacillus (the vibrion seftique of Pasteur). ETIOLOGY. Chiefly met with in the horse, it constitutes one of the most formidable complications of surgical or accidental wounds. Although relatively frequent formerly, it has now become an uncommon disease, owing to the general practice of aseptic or antiseptic methods. Bacteriology. — The malignant oedema bacillus is a facultative parasite, whose common method of existence is as a saprophyte, having a ubiquitous distribution on the surface of the earth, but being especially abundant in cultivated and manured soils. It is therefore necessarily ingested by the herbivora with their food, ancj may be said to be a normal inhabitant of the alimentary canal of these animals, and is present in their faeces. It is doubtful whether it multiplies in the alimentary canal. In cases of malignant oedema the bacillus is confined to the lesions, and is never found in any considerable numbers in the blood during life. In veterinary practice the principal importance of the bacillus arises from the fact that in the herbivora it is a constant invader of the blood and tissues of the unopened carcass, and, on account of its resemblance to the anthrax baciUus, it is likely to lead to errors in diagnosis. The post- mortem invasion of the bacillus starts from the alimentary contents, and frequently begins immediately after the animal's death, being especially rapid if the blood is in a deoxygenated or asphyxiated state. The invasion mainly follows the line of the veins, and in the abdomen 12 MALIGNANT (EDEMA 13 and thorax is soon fairly complete. The extent of the invasion of the peripheral parts is chiefly dependent upon thp rate of cooling of the carcass, and is therefore most extensive in hot weather ; in the height of summer or in the tropics there may be extensive invasion of the peri- pheral blood within twenty-four hours. If the temperature is 70° F. or above, the bacillus may sporulate freely in the blood, but at a lower temperature than this sporulation does not take place. In size the malignant oedema bacillus is a comparatively large organ, ism, being slightly less than 1 /(* in thickness, and in length the single rods vary from 3 /* to 10 /i. Both in the tissues and in the blood and fluid culture media it fre- quently grows out into long filaments, which may be uniform throughout, but generally are segmented at irregular intervals, some of the segments being twice as long as others. The bacillus is motile, but this feature is of little diagnostic value, as the filaments seldom exhibit movement, and the single rods, on exposure to the air, soon cease to move. At a temperature of 70° F., or above, sporulation takes place, the spore, elongated in shape, being either in the centre or towards one end of the bacillus, and not greatly exceeding it in thickness. Staining. — The malignant oedema bacillus is readily stained with any of the basic aniliae dyes. With methylene blue in semi-putrid anthrax blood, the malignant oedema bacillus, unless preparing to sporulate, stains quite uniformly and more ' intensely of a deep dark blue colour than the anthrax bacillus, and, in addition, the ends are rounded ; whereas those of the anthrax bacillus are shghtly concave when staiued in this way. There is no metachromatic reaction with methylene blue, as is the case with the anthrax baoiUus, where the bacillus stains blue and the capsule takes on a purple tint. , The malignant oedema baoUlus does not stain by the method of Gram nor by the methods of Gram-Weigert or of Claudius. Cultivation. — ^The organism has always been regarded as a strict anaerobe, but it can be grown exposed to the air by the Tarroai-Smith method — that is to say, in broth-tubes containing small pieces of sterile healthy liver, or even small pieces of sterile turnip or potato. By this method a moderate amount of gas is evolved— not so much as in the case of the black-quarter bacillus — and by the end of twenty-four hours' incubation the whole medium is rendered turbid, and a slightly putrid, though not sour, odour is noticeable. At this stage the culture is usually composed of single rods. As the medium gets exhausted sporulation begins, and by the end of two or three days the broth clears up, the growth being on the bottom or walls of the tube. Although growth takes place best at 100° ¥., it wiU occur freely at ordinary temperatures. With a stab culture in glucose-gelatine the growth appears some distance below the surface as a whitish line with minute processes. Liquefaction soon occurs, and bubbles of gas are given off. In deep tubes of gluoose-agar incu- bated at 100° r. growth is extremely rapid, taking the form of a white line along the needle track, with short lateral projections here and there, and attended with the formation of gas. Under anaerobic conditions growth takes place on sohdified blood -serum, which is liquefied, and upon potato, without coloration. Inoculation is pathogenic for the following animals : Mouse, guinea-pig, rabbit, 14 SYSTEM OF VETERINAEY -MEDICINE sheep, goat, horse, pig, dog, cat, fowl, and pigeon. The ox is refractory. In the mouse multiphcation in the blood-stream occurs, and the spleen is much swollen. To produce a fatal result in a healthy animal a considerable amount of pure material is required, and must be introduced deeply into the tissues, intramuscular inocula- tion being the most certain. Injected along with other organisms (Bacillus pro- digiosus, etc.), a smaller dose proves fatal. Inoculation by scarification is followed by no result, nor is it possible to infect by ingestion or inhalation. ANIMALS ATTACKED. This disease is chiefly met with in the horse as a complication of surgical or accidental wounds. The ox, although proving resistant to experimental inoculation,^ is said by some authors to contract the disease naturally. The only cases meriting attention are those described in the cow following parturition. Cases are but rarely met with in the other domestic animals, although they are susceptible to artificial inoculation. MORBID ANATOMY. Lesions in the Horse. 1. Traumatic Gangrene. — The tissues in the region of the swelling are reduced to a putrid foetid mass. The skin is separated, necrotic, and sloughed off in irregular pieces. The muscles involved are emphyse- matous, friable, of a pale ochry colour, spotted with deep red or brown patches. The subcutaneous and intermuscular connective tissue is infiltrated with a reddish or pale yellow serous fluid, which extends considerably beyond the hmits of the swelling. The visceral changes are not extensive. The spleen is engorged and much softened.. The myocardium is friable, pale, and ecchymosed about the coronary fissures ; the blood of the right ventricle is uncoagulated and dark in colour. The pericardium contains a small quantity of a clear transudate. The blood is much altered in the veins of the affected part ; it is uncoagulated, pitchy, and exhales a putrid odour. The walls of the vessels are red in colour. 2. Septic Peritonitis. — This is met with as a sequel, to the operation of castration. The lesions are slight and quite out of proportion with the gravity of the symptoms. The abdominal cavity contains a sinall quantity of a reddish serous fluid ; the peritoneal vessels are injected, and their serous coats have a uniform reddish colour, but there are no false membranes, and but sUght traces of inflammation. The inguinal region, stump of the spermatic cord, and scrotal wounds, often show their natural appearance; the connective tissue is shghtly infiltrated. In other cases a clear gelatinous oedema surrounds the cord in its abdominal course ; the infiltration may reach the peri- renal MALIGNANT OEDEMA 15 connective tissue, whilst, on the other hand, it may spread to the sheath and to the subcutaneous tissue of the abdominal wall. The abdominal viscera are normal, with the exception of the spleen, which is softened and somewhat swollen. The pleurae and pericardium contain a serous transudate ; the myocardium appears parboiled and ecchymosed ; the blood is dark and diffluent. The organisms are met with in the blood and peritoneal exudate in the form of rods and filaments. SYMPTOMS. A. In the Horse. In French literature two clinical forms of the disease are described as affecting the horse : 1. A form characterised by its traumatic origin, and the appearance from the first of crepitant swelUngs, and called Traumatic Gangrene. 2. A second form, analogous to the foregoing in its pathogenesis, but differing in its manifestation, consists in the invasion of the peri- toneum following upon castration, and is called Septic Peritonitis. Traumatic Gangrene. — The sjnnptoms arise in connection with a wound, surgical or accidental, characterized at first by a small, hot, cedematous focus, which spreads in every direction with extreme rapidity. At the same time the appearance of the wound is changed ; the tissues take on a livid, shining colour ; suppuration is replaced by the running of a pale yellow or reddish serous discharge. The temperature rises to 103° or 104° F. ; the pulse is rapid ; respiration is accelerated ; the mucous membranes are injected ; the appetite is impaired. In twenty-four hours the oedema extends to a limited area of the body. If it does extend chiefly towards the dependent parts, it also spreads above the wound. The swelling, still hot and tender at the periphery, is softened, colder, and less painful towards the centre. A reddish-brown, frothy liquid with a putrid odour runs from the wound. The face is drawn. The animal, downcast and " at the end of its tether," from time to time shows periods of excite- ment. Certain parts are covered with sweat. The temperature remains at about 104° F. ; the pulse is rapid, feeble, and thready ; whilst the heart-beats gradually become violent, and to such a degree that they shake the thorax and can be heard at a distance. In some animals cerebral symptoms are seen, with violent excitement, muscular con- tractions, and a disposition to bite. At a later period the oedema, spread to a tremendous extent, is softened, cold, and painless. On manipulation the tissues give a sensa- tion of crepitation, indicating emphysema. The interstices of the 16 SYSTEM OF VETERINARY MEDICINE wound contain a sanious and fcetid liquid; [the skin, separated and withered, comes off in pieces ; the muscles laid bare are friable, brown or purple, and their tissue spaces infiltrated with a frothy pale yellow ■ serosity. The patient remains without feeling or action ; the head is hung low or rested on neighbouring objects ; the eyehds are half closed ; the gait is laborious and unsteady ; wasting is rapid ; the flank is hollow ; the hair of the mane or tail is easily pulled out. The temperature sinks below normal ; the pulse is imperceptible, whilst the heart-beats preserve their force ; respiration is slow, deep, and tremulous. Sometimes indications of pulmonary gangrene appear. The animal falls and dies in a state of excitement. In cases afEecting the head, the emphysematous condition of the skin may not always be apparent. The course is always rapid ; the mean duration is from three to five days. Septic Peritonitis. — The cases recorded were aU consecutive to castra- tion. The symptoms of infection appear some days or several weeks (up to two or three months) after the operation. The animal suddenly appears listless and refuses to eat ; colicky pains are noticed ; he lies down with care, and rests extended on his side. In the course of some hours the symptoms are aggravated. Prostration and trembhng of the whole body has set in ; the face is drawn ; the eyes are fixed and the pupils dilated ; the temperature rises to about 104° F. ; the pulse is small and rapid ; respiration is shghtly accelerated ; the colicky pains continue. The animal remains motionless, stretched out on his side. The abdomen is distended with gas, and tender upon pressure. Examination of the inguinal region often reveals nothing in particular ; the operation wounds are covered with pus, but otherwise their appear- ance is normal. Only occasionally does an oedema appear in the region of the inguinal canal, and quickly spreads to the sheath, perineuni, and abdominal wall. Matters quickly go from bad to worse. Prostration is complete ; various parts of the body are bedewed with sweat ; the temperature falls to 100° F., or below ; the patient remains outstretched ; the abdomen is greatly distended ; the mucous membranes have a yellowish colour ; the pulse is imperceptible. Death takes place in the course of twelve to thirty-six hours on an average. B. In the Ox. The only cases worthy of notice are those post-partum ones recorded by German authors under the title of " Geburtsrauschbrand," and even MALIGNANT (EDEMA 17 regarding these an element of doubt occurs. The symptoms described are briefly as follows : The infection always takes place subsequent to parturition. It is preceded by symptoms of septic metritis. Tl^e first signs are loss of appetite, with rigors, diarrhoea, and shght elevation of temperature. SwelUngs develop about the perineum, buttocks, thighs, and sometimes from the commencement in the region of the shoulder, neck, or head. The swelling is at first hot and oedematous ; it extends rapidly, and becomes cold, emphysematous, and crepitant. Death takes place in one to three days from the onset. Post mortem one finds indications of metritis. The connective tissue of the pelvis and around the womb is oedematous and infiltrated with blood and gas. The subcutaneous connective tissue is emphysematous in several places, and at the same parts the muscles appear parboiled, friable, and spongy, of a dirty brown colour, and dissected by a sero- sanguinolent exudate and gas. The blood is normal. The viscera are but little altered. C. In the Sheep. The cases cited in sheep are those occurring in connection with the operation of castration, or with wounds inflicted during shearing or inoculation for sheep-pox. ' The symptoms develop in connection with the woimd, from which there quickly spreads an oedematous swelling, which is hot and painful, whilst from the wound there issues a clear serous discharge. The sheep loses its appetite and becomes dejected and sleepy. If the swelKng develops upon the body or upper parts of the limbs, death is the constant result ; only in cases where the infection is towards the extremities is there any hope of recovery. Cases of intestinal origin are quoted as the result of certain methods of feeding (fermented beetroots). The sjnnptoms were those of peri- tonitis with extensive oedema. D. In the Dog. Infection follows bites inflicted by other dogs, or extensive wounds involving the subcutaneous or intermuscular connective tissue. There is a diffuse swelling, with gaseous infiltration of the tissues. Death follows ia the course of a few days. Nocard met with an epidemic affecting young beagles fed on raw flesh, which ceased on substituting cooked foods. DIAGNOSIS. A. Clinical Diagnosis. 1 . The Horse. — Traumatic gangrene is clearly indicated by the presence VOL. I. 2 18 SYSTEM OF VETEEINARY MEDICINE of a swelling that is rapidly extending, oedematous, hot, and painful at the onset, then emphysematous, cold, and painless in the parts first affected. Simple oedemas, inflammatory or passive, never become crepitant; their tendency always is to spread towards the dependent parts. Certain swelUngs following castration, probably due to a streptococcic infection, appear in the groin and sheath, and extend towards the peri- neum ; they are cold and somewhat tender, but never become emphy- sematous ; they nearly always pass off, and the general symptoms are slight. The septic nature of the peritonitis is to be suspected when the symptoms of peritonitis appear in subjects bearing castration wounds that have not yet cicatrised. Streptococcic peritonitis seen under the same conditions is only indicated by grave general sj^nptoms ; its ter- mination is in other respects the same. MaHgnant oedema is distinguished from erysipelas by the more grave general disturbance and the rapid development of the swelling. The latter in mahgnant oedema becomes emphysematous, and soon displays an outer oedematous zone, an intermediate gangrenous zone, anda central putrefying area. Traumatic emphysema is differentiated from malignant oedema by the fact that in the former no grave constitutional symptoms are shown as a rule, and there is an absence of severe oedema and gangrene of the swelhng with putrefactive changes. 2. The Cow. — The forms of uterine origin are indicated by crepitant external tumours. The diagnosis ought to be confirmed by finding the bacillus and by inoculation experiments. 3. The Sheep.— The presence of emphysematous swellings of traumatic origin, coinciding with a severe general condition, may be assigned to this infection. B. Experimental Diagnosis. For this purpose direct microscopical examiaation, cultivation and inoculation of the fluid obtained from the affected tissues, are employed. The bacillus of mahgnant oedema kills the guinea-pig, rabbit, and fowl, whilst the anthrax bacillus kills the guinea-pig and rabbit, and the black- quarter bacillus kills the guinea-pig only. The examination of the lesions in these inoculated animals is instructive. In the case of anthrax one finds in the guinea-pig and rabbit, in the connective tissue at the seat of inoculation, a clear gelatinous oedema ; in the case of mahgnant oedema a red sanguinolent and frothy oedema. Blapk-quarter in the. inoculated guinea-pig presents close analogies, and the finding of mor- phologically similar organisms has no weight. MALIGNANT (EDEMA 19 IMMUNISATION. Immunisation is effected— (a) By the intravenous inoculation of virulent material. In the ass, by repeating the injection with large doses on two or three occasions, a high degree of immunity can be established, and a subsequent subcu- taneous inoculation results only in the development of a local swelhng and abscess. By means of a series of inoculations of increasing strength hyper-immunisation may by this method be obtained in the horse or ass for the purpose of producing an anti-serum. (6) Immunisation by means of attenuated viruses. Satisfactory results have not been obtained ia this way. (c) Inununisation by means of toxins. This can be effected by the injection of cultures or virulent organic Uquids, sterilised by heat or filtered through porcelain. {d) Serotherapy. — An immunising serum is obtained by means of method (a), and has an antitoxic effect, as well as a direct action, on the bacteria (agglutination), and is considered as promoting phagocytosis. TREATMENT. An early degree of infection may be arrested by energetic surgical intervention, amputation of the infected region, cutting widely, being the best method, but is rarely applicable to animals. Total destruction of a centre of infection by excision or cauterisation is difficult to carry out, as it is always to be feared that the organism may have penetrated deeply at some point of lowered resistance. Deep scarifications of the swelling are indicated, and should be done with a bistoury, as the slough" produced by the actual cautery protects the organisms from the action of the air or antiseptics. Drainage of the deep parts or periphery of the infected area is equally useful. The wounds should be irrigated copiously with a warm antiseptic solution, or with a solution of hydrogen peroxide, and then a dressing apphed, containing some antiputrescent agent — e.g., iodoform or tincture of iodine. Constitutional .treatment includes the administration of difiusible stimulants and tonics. Digitalis and i hypodermic injections of ether or caffeine are required in special cases. Curative serotherapy is indicated in the horse. The results which have been obtained foreshadow the general efficacy of the method. PROPHYLAXIS. Prevention is assured by prompt antiseptic treatment of accidental wounds and the asepsis of surgical wounds. Small deep wounds intersecting the connective tissue, and soiled by 20 SYSTEM OF VETEEINARY MEDICINE earth, dung, or dust, are chiefly exposed to septic complications. The indications are to cleanse the surfaces of the wound by prolonged irriga- tion with an antiseptic solution, and, if necessary, to open up or drain deep wounds. Any accumulated blood-clots are to be removed. An antiseptic dressing must be applied to the part, and be renewed often enough to prevent putrefactive changes from taking place. The rules for surgical asepsis need hardly be impressed, for it is deep infection from hands or instruments that is to be viewed with appre- hension, rather than superficial soiling from dust or simple contact with unsuitable objects. Septic infection subsequent to parturition is to be avoided by anti- septic irrigation of the uterus and vagina, and appropriate treatment of any deep wounds of the parts. In the case of accidental wounds in parts rich in connective tissue, or castration wounds becoming soiled with infective material, preventive serotherapy should be adopted for valuable animals.^ In order to prevent infection occurring from the employ- ment of hypodermic injections, it is necessary to use sterilised water to dissolve the hypodermic tablets, and to carefully sterihse the syringe and needle prior to use. Cases of malignant oedema have been traced to neglect of these precautions. ANTHRAX By H. CAULTON REEKS, F.R.C.V.S:, Examiaer in Pathology, Royal Coltege of Veterinary Surgeons. Synonyms. — Splenic fever ; Splenic apoplexy ; Malignant pustule. French : Charbon. German : Milzbrand. Human Pathology : Woolsorter's disease. In India anthrax is known as " Loodianah disease " and " Manipur horse disease." Definition. — ^Anthrax is a specific infective bacillary disease caused by the entrance into the body of the Bacillus anthracis. ANIMALS ATTACKED. Briefly it may be said that anthrax attacks all animals, including man. In man, however, if we except the possibility of cases arising from the ingestion of anthrax flesh, it does not occur as a natural infection. To man it is communicated directly or indirectly by animals, and takes the form either of a local infection {malignant pustule) or of a combined pleurisy and pneumonia {woolsorter's disease). But it is the herbivora that are the most susceptible, and the com- monest subjects are the ox and the sheep. Next in order of importance and susceptibility come the horse and the pig, the latter animal con- tracting the disease almost invariably by the ingestion of anthrax- infected flesh. 'Dogs, too, and foxes become infected in the same way. Cats, tame rabbits, hares, and wild rabbits are all subject to the disease, as also are guinea-pigs, mice, and rats. Birds are not readily infected, while white rats, old dogs, and amphibians also show a marked resistance to anthrax. These remarks apply to inoculation tests, and inasmuch as it is certain that such methods would insure infection if susceptibility existed, it is safe to assume that naturally these animals are immune. In this connection it is interesting to note that, despite the readiness with which other breeds becoine infected, Algerian sheep possess a natural immunity. 21 22 SYSTEM OF VETERINARY MEDICINE ETIOLO&Y AND GENERAL REMARKS. Among the diseases due to a specific organism anthrax is probably the best known of all. The reason is this : compared with other organisms of the class, that of anthrax is of considerable size. For instance, examination of a droplet of anthrax blood with only a moderate power of the microscope reveals the presence of the bacillus quite easily, and this in the unstained state. Add to this the fact that it multiplies with almost inconceivable rapidity in the blood of the more susceptible animals, and the further fact that with comparative ease it is cultivated outside of the animal body, and it is at once clear that facts concerning its life-history, morphology, etc., quickly followed on its initial dis- covery. It was in 1849 and 1850 that PoUender, and afterwards Reyer and Davaine, first described the rod-like organism, which we now know to be the Bacillus anthracis, as occurring in the blood of animals dead of splenic fever. This was supplemented later by Pasteur's work on fer- mentation, so ably continued by Hansen, which works in their turn stimulated Davaine in 1863 to further consideration of the subject as affecting anthrax, and to a series of observations which ended (in 1873) in demonstrating, just short of actual proof, that the anthrax bacillus was the actual and existing cause of the disease. He, in fact, originated the name Bacillus anthracis. Here Koch took up the running. He it was who observed in anthrax blood the appearances of division, and suggested that multiplication of the bacilli took place in the living body. Moreover, he was able to note this same division occurring outside the body, and to record the fact that spore formation here took place, crowning his work by isolatmg the bacillus in pure culture, and, by inoculating animals with the products, artificially producing the disease. That the bacillus was the cause of the disease was thus proved. The mode of natural spread of anthrax, however, was still obscure. Koch himself, while surmising that infection by way of the intestinal tract was to be looked for, signally failed in his earlier experiments to reproduce the disease by feeding animals on the bacilli and their spores. This, however, followed later. Animals fed on the spores succumbed to the disease, demonstrating clearly enough the way in which anthrax might spread in a natural manner. In the section on the bacteriology of the disease (p. 28) it will be seen that these spores of anthrax stand in much the same relationship to the bacilli as do the seeds to the higher plants. They are thus far more resistant to adverse circumstances {e.g., excessive heat or cold, abnormal ANTHEAX 23 dryness or undue damp, chemical agents, antiseptics, etc.) than are the bacilli themselves. This accounts for much that we now know regarding the manner of outbreak and the distribution of the disease. It explains, for instance, how it is that while anthrax may occur ia a sporadic or even in an epizootic manner, it occurs far more frequently as a marked enzootic, outbreaks being limited to special districts, and showing no tendency to spread therefrom. It explains, too, how the occurrence of the disease will depend on varjdng conditions of the soil and cUmatic influences. It is a well-known fact that marshy, boggy, or swampy land paEbicularly favours the conservation of the spores and the development of the bacilli. Especially does this apply when the land is flooded periodically, and good instances are to be found in the low-lying lands of the Kent and Essex marshes, and the black, loose moulds of the Lincolnshire and Cambridge- shire Fens. The spores in such soil, while the land is in flood and during winter's cold, lie inactive. With the. advent of summer, however, with the draining away of the waters and the steady rise in temperature, activity commences and bacilli develop. It is in the months of June, July, August, and September, therefore, that outbreaks may be looked for and most frequently occur. In passing it may be mentioned that under these circumstances the organic deposit remaining after subsidence of the waters is an extremely suitable medium for the growth and development of the organism. From this it follows that manuring the land with material of a Uke nature, and with the dung from stables and byres, will have an equally favourable efiect in promoting the growth and sporulation of the bacillus. While this occurs in a temperate chmate during the months of summer, it must not be forgotten that spore-bearing material, in the shape of fodder grown on infected areas, is quite capable of giving rise to cases at other seasons. This is, in fact, the only way in which one can account for outbreaks in the months of winter, when the animals are being stall- • fed, and very often on premises without a previous history of the disease. And this applies not only to home-grown produce, but to oats and to made-up feeding material in the form of cake from a foreign source.* McFadyean has isolated anthrax baciUi from imported oats, in the important case of Denny v. Covington. Dunstan has demonstrated experimentally that feeding cake may contain the spores of anthrax. * According to Stockman, a summary of the quarterly incidence of anthrax from 1906 to 1910 shows " that there is a marked and constant drop m the number of outbreaks in the third quarter of each year— i.e., at the time when most stock are on grass— while there is a decided rise when the animals may be assumed to be running in and receiving artificial' food " {Journal of Gonvparatme Pathology and Therapeutics, June, 1911). — Ed. 24 SYSTEM OF VETERINARY MEDICINE Reverting to the subject of manuring, a very real danger of infecting a pasture previously free from the disease lies in using a manure composed of animal matter such as blood or bone. One such case is recorded in the Board of Agriculture Report (Diseases of Animals) for 1908. Ttis outbreak, occurred on a farm where anthrax -A^as before unknown. The owner was able to state that no cattle or sheep had died during the ten • years previous, and the veterinary inspector stated that no case of ■anthrax had recently occurred in the district. About a year before the outbreak bone-manure was applied to one field of grass which had been kept free from animals for the best part of a year. After a crop of hay had been removed from this field, nine cows were admitted for grazing purposes, and the grass formed their sole diet. Three out of the nine cows died of anthrax about a week after being aidriiitted to the field. What has been written here appHes to anthrax as it occurs in a temperate clime and as we know it in Great Britain. But from what has been said it may readily be understood how in a hot climate, with the longer periods of temperature suitable for the development of the organism, anthrax may become a positive scourge.* Below are the statistics of anthrax in Great Britain for the ten years 1899 to 1908: Tears. Animals attacked. Cattle. Sheep. Pigs. Horses. Deer. 1899 634 69 253 30 986 1900 . 668 40 204 44 956 1901 708 76 152 35 . 971 1902 . 1 746 50 192 44 — . 1,042 1903 . 1 809 48 234 51 1 1,143 1904 . 1 1,115 62 365 47 1,589 1905 1,001 53 210 53 1,317 1906 999 83 231 35 1,348 1907 1,163 66 190 37 1,456 1908 1,107 34 220 58 1,419 When this is compared with the statistics for the ten years 1889 to 1898 it is found that there is a steady, if not a large, increase in the * Stockman points out that, according to available evidence,^ anthrax does not arise mainly, or even to a great extent, from previous oases of the disease on the same establishment. In great Britain statistics from 1902 to 1906 show that 83-5 per cent, of the outbreaks, occurred in farms which had not been previously infected (" Epizootology of Anthrax," Journal of Compa/raime Pathology cmd TherapeuUcs, June, 1911). The same authority is of opinion that from this fact, and also from the in- formation derived from a consideration of 1,257 outbreaks of anthrax which occurred on farms not previously infected, and where ground infection could not ANTHRAX 25 number of cases returned, the average number per year for the first decade bemg approximately 783, while for the second decade it is 1,222, or an increase of 439 per annum. On this we need not speculate very largely. We would say, however, that it does not necessarily point to any great spread of the disease, nor to failure of the regulations which deal with it. ' Rather, we beheve that with more modem methods of diagnosis such cases as have hitherto escaped detection are now recognised. It is probable, too, although the efforts of the Board of Agriculture have not yet confirmed the suggestion, that anthrax may be as prevalent among sheep as it is among cattle. If that be so, and the same attention is paid to the rep'orting of sudden deaths in these animals as is now paid to those among cattle, then we may look for a further increase in the total number of reported deaths from anthrax. Regarding the geographical distribution of the disease, we may say briefly that it is world-wide, and that in nearly every country, under one of its many names, anthrax has been recognised. BACTERIOLOGY. 1. The Bacillus. (a) In the Blood. — Anthrax bacilli are found in the blood of the living animal only a very short time previous to death. A minute drop of fresh anthrax blood spread on a slide and examined microscopically reveals the baciUi in large numbers. They appear in this as small, transparent, non-motile rods, and may be observed with only a moderate magnification. In this manner, however, if we except the evidence furnished by a chnical history of the case, they may be mistaken for other bacilli, notably those of malignant oedema or of putrefaction. In size the baciUi range from I '5 to 2 microns long, and from 1 to 1 '5 microns broad. These are the individual segments. It is characteristic of anthrax, however, that the multiplying bacilli after division show no tendency to separate, but to hang together end to end in chain-like form. Even in the blood, whose circulatory movements interfere with the formation of chains of any great length, this tendency is still maintained. It is thus that in the examination of anttrax have operated, that the evidence is strongly in favour of the view that the great majority of outbreaks in Great Britain are due to infection from without, particularly by material brought in from countries where anthrax is very prevalent. He also points out the difficulty of obtaining definite evidence that foodstuffs carry infection, this being due in part to the circumstance that the infected portions may have been ingested by the animal prior to samples being taken, and also that it is only possible to examine small samples of' the suspected material experimentally. As regards the most likely explanation of infection in grain or meal, he is of opinion that during transit from infected countries these foodstuffs " become con- taminated by infective material from dry hides, which on account of their light weight are often stored on the top of other cargo." He also points out that anthrax is " exceptionally prevalent in certain districts where imported hides are tanned and wool is washed, the assumed explanation being that the drinking-water becqmes contaminated by the sewage from the factories. In the course of inquiry it has also been foimd that the disease is exceptionally prevalent on certain sewage farms which are known to receive tannery and knackery drainage." — Ed. 26 SYSTEM OF VETEEINAEY MEDICINE blood we are able to observe chain-like forms of from 5 to 20 microns in length. The fact that these 20- micron lengths are not individual organisms, but are composed of several bacilli end to end, is revealed by close examination. Along the length of the chain will be noted numerous fine, transparent, transverse markings. These indicate the points of division between the individual baoiUi. While at times the line of demarcation between the adhering bacilli appears to be perfectly straight, at others we get a biconcave or biconvex marking, the two latter appearances depend- ing on whether the ends of the bacilli are dimpled, or are rounded off after the manner of the proximal end of a phalanx. This variation in the shape of the ends of the bacilli appears to have some connection with the different methods of staining. The body of the bacillus is composed of a finely granular protoplasm, while around this, and revealed by appropriate staining, is a well-marked capsule. When several of the bacilli are end to end, this capsule sometimes appears to be common : to the whole chain. Such are the appearances of the bacilli in the blood. From a sample of such blood it is easy to isolate the baoiUus by making gelatine or agar plates, and so observe their characteristics in culture. (6) In Plate Culture.— Aiter twelve hours' incubation of the inoculated plates at 37° C, growth may be looked for, the separate colonies appearing as minute roimded points, around which the gelatine is liquefied. The plate should be placed on the table of the microscope and the colonies examined under a low power. They ' may then be readily recognised. Each has the appearance of a light grey, shining mass, consisting of numerous wavy bundles, the latter being likened by several writers to curling locks of hair. From one of these colonies an impression preparation should be made. This is done by simply dropping a cover-glass on to the colony, and afterwards staining and mounting the adhering growth. Under examination with a high power this preparation reveals a characteristic of anthrax, which it always exhibits when grown under artificial conditions — ^viz., its tendency to form unbroken chains. The wavy looks of hair are seen to be composed of innumerable interlacing filaments of a won- derful delicacy of form and arrangement, the filaments themselves consisting of anthrax bacilli placed end to end without a break. This appearance is very nearly, if not quite, diagnostic of an anthrax culture, no other pathogenic organism growing in a similar manner.* . (c) In Bouillon. — ^In this medium irregiUarly spiral threads are seen suspended in the liquid after twenty-four hours' incubation at 37° C. Later, as growth becomes more abundant, a flocculent mass is deposited at the bottom of the flask or tube. Here, again, the growth is composed of interlacing chains of the bacilli. The bouillon is not rendered turbid. {d) In Gelatine (Stab Culture). — Cultivated in this way, anthrax grows as a white granvdar line along the needle-track. If the proportion of gelatine in the medium is low — that is, if the medium is not too stiff — a characteristic appearance is pre- sented. In about forty-eight hours numerous delicate feathery growths radiate out from the inoculating stab. From these other lateral rays are given off, and the whole has a feathery appearance, somewhat resembling thistle-down. The radiating rays are always longer near the surface of the medium. On the immediate surface of the gelatine, however, little or no growth takes place. , In this position liquefaction of the medium occurs, gradually spreading down the stab and into the medium. In this way the whole of the gelatine may become liquefied, and the anthrax growth Anally deposited at the bottom of the tube. A slope culture on gelatine shows a thick felted growth, on the ed^es of which the hair-like appearances, as described in plate cultures, may be recognised. Along the line of inoculation the gelatine is liquefied. * By some workers it is claimed that this characteristic growth of anthrax is obtained in sufficiently large degree after only five hours' incubation, thus rendering the ihaking and examination of gelatine plates a useful adjunct to other methods in cases where a ready diagnosis is required concerning a specimen of blood showing a mixed infection. ANTHEAX 27 (e) In Agar. — ^In. this medium, botli in stab and slope preparations^ much the same appearances are presented as in similar preparations in gelatine. There is, however, no liquefaction of the medium. (/) On Potato. — On this medium a duU white felted mass occurs along the line of inoculation, but shows no tendency to spread therefrom. It shows no special characters. In or on all these media the manner of growth is that specially characteristic of the organism — ^namely, that of long interlacing leptothrix filaments. (gr) Biology of the BacUlua. — ^Under this heading probably the first point of interest to the veterinarian is the fact that the BaeiUus anthracis is aerobic. For its complete development free exposure to the oxygen of the air is indispensable. In this we find explanation of the fact that, white the anthrax bacillus rapidly multiplies in the blood-stream, depending for its existence on the oxygeri there present, yet it never there forms spores. For this further phase in its development exposure to the air is necessary. It further explains the fact that an anthrax carcass rapidly putrefies. The blood, robbed of its oxygen by the rapidly multiplying bacilli, is quickly invaded by anaerobic organisms from the intestine, while under this invasion, and with all available supply of oxygen exhausted, the anthrax bacilli degenerate. This point has a twofold practical bearing. We understand from it how it is that in the blood of an anthrax carcass allowed to lie long after death no single bacillus can be demonstrated, where previously they existed in imtold numbers. We understand, too,, the need for disposing of anthrax carcasses intact,, recognising the fact that spiUing the blood, and consequently exposing it to the air, is assisting the spread of a highly virulent material. The question of temperature, too, is important. Anthrax bacilli thrive best at 35° C. Below 12° C. no growth takes place.* Neither does growth occur above 45° C, while prolonged exposure to a temperature of 60° C. kills them outright. And in other respects the spore-free baciUi exhibit comparatively low powers of resistance. Light, and more especially sunlight, impedes their growth. The action of the gastric juice is absolutely inimical to them, and they are accordingly destroyed in the stomachs of healthy aniinals. Even if kept at ordinary temperatures for a few days, they are usually found to be dead. They may, however, be subjected to cold at the freezing-point without dying. That they are rapidly kUled oS under the process of putrefaction we have already intimated. Also, we have pointed out that in the absence of oxygen, degeneration takes place. It remains to be said, however, that, while certain of its vital functions are best carried on in the presence of this gas, the Bacillus anthracis can grow in its absence. {h) Staining Reactions of the BacUlus. — The Bacillus anthracis stains easUy with solutions of the basic aniline dyes. The method, however, which is of great interest to the veterinarian is that introduced to English practitioners by Sir John McEadyean. In this method the stain used is a 1 per cent, aqueous solution of methylene blue, rendered slightly alkaline by the addition of ^ per cent, of sodium bicarbonate. With this the film of suspected blood is stained for half a minute to a minute, and then afterwards simply washed in water. The picture presented by an anthrax film stained in this manner is such that in animals recently dead of the disease — in cattle, at any rate — a means of diagnosis is provided that is nearly constantly reliable. The appearance of the flhn is, in fact, remarkably characteristic. Not only have we the bacilli .stained a deep blue, but we have also other elements in the film stained a pronounced violet or reddish-purple. Close mspection of such a fihn reveals the fact that the violet-stamed portions have some close connection with the envelope or capsule of the bacillus; for, while such violet-stained portions are found detached and plainly apart from toe bacillus itself, we note also that the coat or envelope of the bacillus is traceable as a thin violet line immediately round the body. , , , , , . • This peculiar double-staining reaction with alkahne methylene-blue solution * On this knowledge is based the Board of Agriculture's regulations dealing with deep burifil of the carcass. The temperature of the ground, save at the surface , is always below 12° 0. 28 SYSTEM OF VETERINARY MEDICINE appears to be a characteristic of anthrax alone, and is of the utmost service as an aid to diagnosis. An additional point of interest in the staining reactions of the bacillus is that it takes the stain of Gram, or, in other words, is Gram positive. Briefly stated. Gram's method is to stain with aniline gentian violet, and afterwards to decolorise with a solution of iodine, finally rendering the decolorisation complete by treating with absolute alcohol or methylated spirit. 2. The Spores. As we have said before, just as the seed is to the higher plant, so is the spore to the bacillus. Now, the spore of anthrax may first be seen in a bacillus about to sporulate as a small, highly refractile speck in the centre of the protoplasmic body. This gradually increases in size until it forms an oval body about the thickness of the baciUus. The bacillus itself gradually loses its staining properties, and finally disappears, allowing the spore (an oval, highly refractile body) to lie free. Most observers are agreed that sporulation only occurs outside the animal body. This, therefore, as well as the marked resistance the spores sho* to adverse circumstances, furnishes us with another and a weighty reason for the necessity of disposing of anthrax carcasses intact. As a result of the high resistance they show to ordinary outside circumstances, the spores of anthrax, when they are set free from an infected animal and have got into the soil, may remain there for a considerable time. By some observers this time has been put at twelve months, while others say it may be many years — ten or even more. It is sufficiently long, at any rate, to account for the regularly-ocomrring oases on infected pastures, and to explain h9w the disease may be spread by means of feeding materials, such as cake, fodder, or roots, and by sofl and running water. In this connection it is important to remember that the gastric jidoe, which is able to kiU off most of the baoiUi taken into the stomach, is unable to injuriously afEeot the spores. These are able, therefore, to pass along to the intestines, and so give rise to that form of anthrax with which the English veterinary surgeon is, perhaps, most fanuliar. From what has already been written, it will be understood that for vegetating, the spores find a favourable medium in the animal body. Under certain circum- stances, however, they may do so outside of it. Where temperature and other conditions are favourable they may spring into activity, resume the bacillary form, and again sporulate in the soil and in surface-water. This explains how, in tropical climates, the contagium may exist in aU virulence for many years without the occurrence of fresh cases to maintain the running. For the formation of spores free oxygen and a suitable temperature are required. The temperature most favouring sporulation is 32° to 36° C. It may, however, take place at a temperature as low as 14° C. or as high as 43° C. Thus it follows that abundant sporulation occurs at a temperature varying from 20° to 25° C, or, in other words, at the ordinary temperature of summer heat, or at that of a dwelling-room — a point of high practical importance. Above 43° C. sporulation ceases. Further, if the bacilli are kept at this temperature for eight days, they fail afterwards to sporulate when grown again at a lower temperature. The spores are killed by boiling for five minutes ; but the application of dry heat at 140° C. must be maintained for several hours to destroy them with certainty. Experience has shown that the baciUi themselves are killed by cold only in rare instances, resisting a temperature of 10° C. for three days, from which it follows that the spores, with their higher powers of resistance, retain their vitality for an indefinite time under the same conditions. As bearing upon the important role played by the spores in the spread of anthrax, we would refer to the case of Denny v. Covington. Here the deaths of certain horses were plainly traced to feeding on a quantity of oats to which anthrax spores were adherent. More than that we need not say here. The whole of the evidence in the ease, however, more particularly that of Sir John McFadyean in describing his experiments, makes most interesting and instructive reading.* * Vide the Veterinarian, vol. Ixix., p. 62. ANTHEAX 29 The Action of Germicides on the Bacilli and their Spores. .1. ^^°Mv*®m?*® "*, oommou use for this purpose are rapidly effectual in destroying the bacilli. Thus they are kiUed by perchloride of mercury (1 in 30,000), by creolin (1 m 16,000), and by carbolic acid (1 in 100). > /• j The same agents, with the exception of carbolic acid, are equally effective in disposmg of the spores. A 1 in 1.000 solution of perchloride of mercury kills them m ten mmutes, and a 3 per cent, solution of creohn in forty-eight hours. It is im- portant, however,' to note that the spores remain virulent after immersion for twenty days m a 5 per cent, solution of creosote, and for' nineteen days in a 10 per cent, solution of oarbohc acid. On the other hand, they rapidly succumb to 2 per cent, watery solutions of chlorine, iodine, or bromine. y^'^iv *" J ^°^^ especiaUy sunhght, has also a modified germicidal effect on both the bacilh and their spores, impeding, and even entirely arresting their development. MOBBID ANATOMY. The morbid changes in anthrax are those brought about by (1) the engorgement of the capillaries by the bacilli ; (2) the deprivation of the tissues of oxygen ; (3) the action of the toxins elaborated by the bacilli. Accordingly, we find on post-mortem, hsemorrhages in practically all the organs of the body ; a tar-Uke, non- coagulating condition of the blood ; serous, gelatinous, and hsemorrhagic infiltrations of the subserous, sub- mucous, and subcutaneous tissues ; considerable swelling of the spleen, and a diffluent condition of its pulp, together with inflammatory changes in the substance of the lymphatic glands generally, and in the Hver and the kidneys. On remoying the skin the first thing that strikes one is the amount of yellow, gelatinous exudate. This in some positions is very considerable, more particularly along the neck and down the traphea. The vessels of the skin itseK are tensely filled with blood, while on the iimer surface of the skin and in the subcutaneous tissues generally, appear well-marked blood extravasations up to the size of a shilling. These same extrava- sations are found also in the substance of the gelatinous exudate wherever that appears. Such muscular tissue as is now exposed shows considerable softening, is flabby with contained inflammatory exudate, is considerably darker than normal, and is spotted with blood extravasations. It may be takeuj too, that the whole of the muscular tissue of the body, including that of the heart, is in a like condition. On opening the abdominal and the thoracic cavities there is found, in place of the normal straw-coloured lymph, a blood-stained, inflammatory exudate — this in considerable quantity ; while the gelatinous exudate already noticed beneath the skin is found to be also infiltrating the subserous and submucous connective tissues. This is particularly notice- able beneath the serous coat of the mesentery, in the neighbourhood of the kidneys, and in the mediastinal cavities, notably the anterior. The 30 SYSTEM OF VETERINAKY MEDICINE glands of the mesentery and the mediastinal glands are swollen, contain blood extravasations, and are infiltrated with the gelatinous exudate. The spleen calls for special mention. Almost constantly it is greatly enlarged (up to four or five times the normal size), and may reach the weight of 30 or 40 pounds. Its capsule is tense and blood-stained, and often raised in tumour-like swellings ; while its pulp, abnormally soft, is dark red, almost chocolate in colour. In cases of considerable enlargement softening of the pulp occurs until it is actually diffluent. In fact, a spleen in this condition, if incised and suspended, will drain itseM of its pulp almost entirely. With regard to the other internal organs, it may be put briefly that they all show signs of intense congestion and actual blood extravasations, with degenerative changes as a consequence. Thus we get degenerative changes in the parenchyma of the Uver and the kidneys. Haemorrhages and patches of necrosis occur along the course of the alimentary canal, the haemorrhages being sufficiently extensive to render the intestinal contents bloody. The lungs are engorged with blood, and the whole of the mucous membrane of the air-passages reddened and hsemor- rhagic, while the trachea and bronchi contain a frothy, blood-stained discharge. All the other organs of the body — the sexual organs, the urinary organs, the saUvary glands, bones, articulations, etc. — in fact, all struc- tures supplied by the infected blood — participate in the changes men- tioned, haemorrhages and blood-stained gelatinous exudations being the main naked-eye characteristics. Everywhere the blood is abnormally dark in colour, exhibits a peculiar iridescefice described as tarry or vamish-hke, and shows little or no tendency to coagulate. Microscopic examination shows numberless anthrax bacilli in the plasma, considerable alterations in the size and shape of the red cells, and a marked degree of leucocytosis. In this country it should not often happen that the veterinary surgeon should be able to observe the foregoing post-mortem appearances, for the prophylactic measures insisted on by the Board of Agriculture demand that the carcasses of all animals dead of the disease be buried or burned intact. Before proceeding to an actual post-mortem, however, an anthrax carcass often offers a few points for consideration that may, perhaps, be best mentioned under this heading of morbid anatomy. In cattle, for instance, who usually die from the so-called apoplectic form of the disease, the cadaver is markedly tympanitic, while from the natural orifices there is considerable exudation of a blood-stained, frothy discharge. Usually,- ANTHRAX 31 too, the last few evacuations of faeces (probably passed involuntarily and nearly always found near the carcass) are distinctly hsemorrhagic. Much the same may be said in the case of sheep. Here, again, the carcass becomes rapidly tympanitic, and from the natural orifices issues the same frothy, hsemorrhagic discharge. In horses and in pigs, where the acute, apoplectic, or intestinal form of anthrax is probably not the common one, there may usually be found diffuse swelliags (the " anthrax carbuncles " of some writers) about the throat and down the neck, which swellings when incised exude the blood- stained, gelatinous exudate so characteristic of the disease. Finally, it may be mentioned, with reservations which will be given under the heading of diagnosis, that all the lesions, the blood, and the exudates contain the anthrax bacilli. SYMPTOMS. In Cattle. — It is not often the veterinary surgeon is afforded an oppor- tiHiity of noting the symptoms of anthrax in cattle. Usually the first intimation he has that he may be deahng with such a case is that an animal is reported to him to have been found dead, either at pasture or in the house, without previous noticeable illness. Or it may be that the veterinary surgeon will receive with the report of the death a history of slight " hoven " or staggers — nothing more than that. Even in cases sufficiently protracted to allow the symptoms to be observed, anthrax in cattle runs an extremely rapid course. Infection has taken place by ingestion, and in a short time symptoms attributable to the invasion of the blood-stream by the bacilli make their appearance. In otlier words, we have all the evidence of acute fever, coupled with the effects of the deoxygenated blood and of the toxins of the bacillus on the higher nerve centres. The temperature runs up to 106° or 107° F., and the pulse, much increased in its number of beats (80 to 100 or 120 per minute), is thin and hardly perceptible. Rumination is suspended, the horns and other extremities are cold, and occasional rigors manifest themselves in various parts of the body. The animal separates itself from the rest of the herd, and is found to be standing in a dazed, stupefied condition, labouring hard for breath, and reeling and staggering in its gait if asked to move. The visible mucous membranes are intensely injected. Often there are symptoms of colic, and nearly always there is marked irritabiUty of the intestmes, manifested by the evacuation of more or less fluid and blood-stained faeces. The condition of coma rapidly increases, until finally the animal gets down and dies in convulsions. 32 SYSTEM OF VBTEEINAEY MEDICINE Death may occur thus suddenly, even as the veterinary surgeon is watching the case ; or in a few instances, though few indeed, the animal may linger on for a period of twelve hours or so. The above is the usual run of the symptoms. It must not be forgotten, however, that cases may be met with in which there is nothing more to note than the abnormal temperature, other signs of disturbance, such as , the diarrhoea and marked dyspnoea, being wanting. These cases, as we shall afterwards mention (see Diagnosis, p. 38), are extremely liable to be mistaken for an ordinary acute attack of pneumonia, and may linger on for so long as forty- eight hours. It should here be noted that usually the first case in an outbreak runs the course first • described. ' If, however, the temperatures of the other cattle of the herd be taken at this time, it will be found that perhaps one or two, or even more, of them are showing a rise. Such cases — ^for cases of anthrax no doubt they are — usually pass off with nothing further to note. By some writers the appearance of anthrax " carbuncles " is referred to as occurring in cattle. Using the term " carbimcle " as applied to the local inoculation form of anthrax as seen in man, then the existence of such a lesion ia cattle must, to say the least of it, be most rare — in this country, at any rate. Occasionally very diffuse, painless swellings may ' be noted, commencing in the neck, and extending from there to beneath the chest, together with like swellings in other parts of the body. These, however, are very far from approaching the size reached by similar swellings, to be afterwards described, in the case of the horse, and very often only succeed in maldng their presence known at post-mortem. Patches of degenerated tissue implicating the deeper structures of the skin of course occur. That any great evidence of this, ia the shape of discoloration and swelling, is given during life, however, is doubtful. It is better, therefore, to reserve the term " carbuncle " for such forms of anthrax as are purely " inoculation " forms. Before leaving this section it will be well to refer here to those cases of submaxillary enlargements suddenly occurring in cattle in this country, implicating the tongue, sometimes extending down the neck to the dew- lap and chest, and variously known as " blain," " gloss-anthrax," or " hawks." It is permissible to doubt that these cases are anthrax at all. Certainly the existence of the anthrax bacilli in the swellings has never been demonstrated. Moreover, it is a matter of ordinary clinical know- ledge that such cases very frequently recover.* In the Horse. — Equine anthrax may manifest itseK in one of two ways : It may occur with a large amount of swelling round the throat, which * See note on Gloss-Anthrax at end of chapter, p. 46. ANTHRAX 33 swelling gradually increases in size, and extends down the neck to the chest ; or it may occur without this lesion, and simply run the course of an acute enteritis, accompanied by the exhibition of severe abdominal pain. In the first instance the symptoms offered for observation are such as to be almost diagnostic, the head and neck swelling, with its tendency to gradually enlarge, and with the exudation therefrom, when pricked, of a thin serous discharge, being the main characteristic. With this, as in cattle, there is also all the evidence of an acute febrile condition. The temperature runs up to as high as 105°, 106°, or even 107° F. The pulse is increased in number up to as many as 120 per minute, and is weak and thready. The mucous membranes are deeply injected, and this is particularly noticeable in the conjunctiva and in the cavities of the widely distended nostrils. The surface temperature is irregular. The coat is hard and staring, and muscular tremors affect various parts of the body in turn. Later, patchy perspirations bedew the body ; the breathing becomes laboured and largely abdominal ; and very evident interference with the higher nerve centres, as manifested by stupor and a reeling gait, makes its appearance. The faecal evacuations, at first normal in consistence, become sloppy, have a peculiar greasy appearance— suggesting, as near as description will allow, an admixture of linseed oil — assume a dark, nearly black, colour, and sometimes, though not always, become watery and blood- stained. The swelling about the head and neck increases ia volume and in tenseness, setting the head and neck almost immovable on the trunk, and giving the animal the appearance more of a hippopotamus than a horse. Respiration grows more and more laboured ; a thin hsemorrhagic discharge issues from the nostrils ; the patient is unable to swallow, while strings of tenacious saUva hang from the mouth ; perspiration becomes more profuse, and the pulse grows weaker and weaker, until at last it is imperceptible. Finally the animal goes down, and expires in convulsions. With a train of symptoms such as these, death may occur in from twelve to thirty-six hours. On the other hand, the case may, and often does, linger on for four or five days. The second set of symptoms exhibited in equine anthrax are, as we have just said, simply those of an acute enteritis. In fact, it may be stated pretty definitely that infection has commenced in this instance in the intestine, and that the case will offer nothing more for observation than the ordinary symptoms of rapid inflammation of the bowels. VOL. I. ^ 34* SYSTEM OF VETERINARY MEDICINE An attack of shivering ushers in the symptoms. The pulse becomes enormously quickened in number — ^hard and wiry at first, later weak and thready. Abdominal pain is manifested by the animal continually going down and rising, and these pains, all the while continuous, grow gradually in intensity. The intestines commence to empty themselves in an irritable maimer, small quantities of faeces being passed at frequent intervals. The tail is outstretched and quivering, muscular tremors afEeot various parts of the body, and intense restlessness, almost approaching mania, is manifested as the case runs its course. Later, profuse perspirations bathe the body, the respirations grow quicker and quicker, and the pulse, save at the radial, becomes im- perceptible. Later still the excitement and the mania give way to a dull stupor. The animal reels in his walk, the eyes grow amaurotic, and the sweats grow cold. Finally the animal drops and dies in convulsions, in from five, six, or seven hours after the commencement of the symptoms. In Sheep. — ^As in cattle, the course of anthrax in sheep is rapid. In most instances, beyond what appears to the shepherd an apoplectic seizure, suddenly followed by convulsions and death, nothing is seen. At times, however, a case may be sUghtly more prolonged, although even then it is rapid. In such instances, then, much the same symptoms as are shown by cattle will be noticed here — namely, a great rise in tempera- ture, tremendously increased respirations, rapid and quickly failing pulse, irritability of the bowels and blood-stained faeces, together with periods of excitement, succeeded by stupor, convulsions, and death. In Pfes. — ^Anthrax in the pig is most rare withbut a history of the animal being previously fed either on slaughter-house offal or on the flesh of an animal dead after only a brief illness. Add to this the fact that there is in nearly every case a most marked and characteristic swelling of the throat and neck, and little more need be said. We give here, however, the symptoms attending the deaths of twenty-eight pigs at Witham :* " Swelling of the throat, dulness, inclined to lie about, but move- ments fairly brisk when disturbed ; appetite and faeces normal at outset, and later retnained so. Conjunctivse' deeply injected ; no discharge of froth or blood from nostrils, eyes, or anus. No cough, but a choking, stertorous noise occasionally heard when an attempt was made to swallow food. Some difficulty in breathing as death approached. Temperature, 105° to 106° F., declining before death. The swelling, beginning in the intermaxillary region, rapidly extended over the jaws, face, and * Vide Journal of Convparative Pathology and Therapeutics, vol. six., p. 247. . Anthrax 35 parotids, and down the lower aspect of the neck. It attained a large size, was tense, painful on manipulation, did not pit, closed the eye (usually only one), and gave the skin of the snout a glistening, shiny appearance." In this outbreak the pigs died in from eight to twelve or sixteen hours after the appearance of the swelling, the younger pigs, as might be expected, dying most quickly. Several attempted to feed an hour or so before death, which occurred very quietly and quickly. DIAGNOSIS. Post-Mortem. — Seeing that the disease in most animals is nearly always rapidly fatal, the diagnosis of anthrax will depend on demon- strating the existence of the bacilli in a stained film prepared from the suspected blood or exudate from the dead animal. In fact, no case in which anthrax is in any way suspected should be allowed to pass unless this examination is made. Fortunately, in the case of cattle and sheep, the animals in which we most frequently meet with anthrax, this method is productive of rehable results. The most suitable stain for this purpose is the alkahne methylene blue already referred to on p. 27. The peculiar double-staining reaction with alkaline methylene-blue solution there described appears to be a characteristic of anthrax alone, and a film exhibiting it in marked degree may be diagnosed as anthrax with an amount of certainty almost approaching the absolute — that is, we repeat, in the case of cattle and sheep. Practically the only objection of any weight to be urged against this method is to be found in cases where the carcass has been allowed to lie for a long time after death before an examination is requested. In the deoxygenated blood the anaerobic bacteria from the intestine commence to multiply, while the anthrax bacilli under this invasion rapidly degenerate and die off. Proportionate, therefore, to the degree of putre- faction, anthrax bacilli have become fewer in the blood, while others, from which they have now to be distinguished, have taken their place. This condition, if far advanced, may of course render diagnosis with the microscope impossible, for a stage is finally reached where the blood is occupied by none but putrefactive bacteria. If, however, the putrefactive process is not too far advanced, if anthrax bacilli, though only few in number, still exist, then a diagnosis may yet be made, even in these cases of mixed infection. Putrefactive bacteria, or the bacilli of rmlignant oedema, may be fairly readily recognised. They are not nearly so numerous in the film, as the bacilli in a case of anthrax examined shortly after death. They are further reco^ised by 36 SYSTEM OF VETEEINAEY MEDICINE their relatively greater length and thickness as compared with those of anthrax, by their evident inclination to form chains, and, above all, by the intensity with which they stain. Moreover, the well-marked envelope, so noticeable in anthrax, is absent. It follows, therefore, that if with bacilli showing these appearances, other bacilli are discovered com- paratively shorter, with a violet- stained contour, and with an appreciable amount of violet- stained debris external to the bacilli themselves, but immediately adjacent to them, we are dealing with a case of mixed infection ; that the occasional bacilli showing the double- staining reaction, and perhaps assisting in the diagnosis by showing a more or less regular segmentation, are those of anthrax, and that invasion of the blood- stream by the putrefactive bacteria has been subsequent to this. As the putrefactive process above referred to commences in the intes- tines, it follows that the peripheral vessels are the last to be invaded. This is a point of practical importance, for it sufficiently indicates the wisdom of always selecting blood from the extremities for the purposes of examination. A further point of importance in making a diagnosis by microscopic examination of the blood is to remember that in cases of sudden death from causes other than anthrax (notably lightning- stroke, sudden heart failure, or rapidly fatal pulmonary congestion) the bacilli of maUgnant oedema may be found ia relatively large numbers in the blood very shortly after death. In fact, they follow decease so early that one may possibly be led to assume they were in the circulating blood during life, and that therefore they must be those of anthrax or other specific disease. Again, however, a reference to their characters as just described should render error unlikely. Moreover, in any film quite innocent of anthrax, even where putrefactive bacilli or those of malignant oedema are present in large numbers, it will be noticed that the film considered as a whole — that is, before being placed imder the microscope at all — has not stained with the uniform density that marks a film of anthrax. In such a case the merest flooding of the stained film with the water necessary to de- colorise it, is successful in immediately removing the stain to the extent of leaving a barely discernible film for examination. In anthrax, on the other hand, comparatively lengthy washing leaves a film that is deeply stained. Should any great doubt exist, and a post-mortem be deemed in- advisable, then this method of blood-film examination should be suc- ceeded either by platmg out gelatine inoculations of the suspected material, or by inoculation of a susceptible animal. As these are purely laboratory methods, we do not propose entering into them here. In such ANTHEAX 37 a case the practitioner will be well advised in forwarding samples of the suspected material to an expert he can trust. Although in cattle and in sheep this method of blood-film examination is nearly constantly reliable, in the case of the horse and the pig it is not so. While in some instances the blood may swarm with typipal anthrax bacilli, in others the bacilli are quite undemonstrable, notwithstanding the fact that the clinical symptoms unmistakably poiat to anthrax. Here examination of the blood should be followed by examination of films prepared from the exudate ia the throat swellings, where these exist and this may need to be further followed by examination of section prepared from the throat glands or the spleen before demonstration of the bacilli is possible.* In some cases where the existence of the disease has not even been suspected,- as, for instance, where the ordinary clinical symptoms have been aberrant or altogether wanting, an actual post-mortem is sometimes proceeded with. In the case of the ox this is not carried very far before the true nature of the case is reahsed. The changes described in the section relating to morbid anatomy afford unmistakable, almost in- disputable, evidence, more especially the condition of the spleen. The same remark applies to sheep. In the case of the horse dead of the disease in its acute form, and without the characteristic throat and neck swellings, there is just the ordinary evidence of an acute septicaemia. The post-mortem of one of the horses as related in the case of Denny v. Covington is an instance of this : "When the skin was stripped off there was a jelly-Uke substance beneath. On opening the abdomen there was a discharge of a large quantity of yellowish-red fluid — some 2 or 3 gallons. When the bowels were removed, it was noticed that the glands along the upper surface of the bowel were very much enlarged, and of a dark reddish colour, some of them being as large as an orange. Between the folds of the mesentery there was a gelatinous material similar to that under the skin. The large intestine showed discoloured patches, some about the size of a six- penny bit, and others as large as half a crown. The small intestine showed a few discoloured, reddish-purple patches, but the discoloration was not so extensive as in the larger bowel. On opening the bowel there was a certaia amount of reddish-coloured fluid mixed with the contents. It appeared like broken-down blood. The Uver seemed normal in size, but in, cutting across it the blood which flowed out was very dark in colour. The spleen was about the ordinary size, but its surface was mottled with * Journal of Comparative Pathology and Therapeutics, vol. xix., p. 248. 38 SYSTEM OF VETEEINAEY MEDICINE spots, the colour of a mulberry. The kidneys contained a large quantity of muco-purulent material."* Unsuspected before the post-mortem (the horse was supposed to have died from twisted bowel), microscopic examination of the blood showed the cause of death to be anthrax. In the pig, too, if we except the characteristic throat swelling, the classical lesions are wanting. It so happens, however, that the throat swelling is so constant as to be pathognomonic, and on incision shows the changes usually occurring in an anthrax enlargement. Lesions elsewhere are very insignificant. As a matter of fact, the disease appears to localise itself in the throat and stomach. On removing the tongue, larjmx, etc., large ulcers covered with necrotic tissue are found in front of the epi- glottis, bilateral, but seldom the same on each side, averaging a penny- piece in size, and approaching the circular in shape. This process of necrosis appears to commence in the tonsils, and to spread therefrom, giving a greyish, diphtheritic appearance to the affected parts. The gastric mucous membrane is deeply congested, and the intestinal mucous membrane is congested also, but less in degree. The mesenteric glands are more or less swollen and congested. The spleen, however, and all other organs appear healthy, while there is quite a remarkable absence of the general effusion and blood extravasation so noticeable a feature in other animals.t During Life. — If we except the subacute form as it occurs in the horse and the pig, the diagnosis of anthrax during life offers considerable difficulty. Here the protracted course of the disease and the characteristic swellings enable one to arrive at a more or less correct decision. The latter, in fact, may be said to be almost certaiinly pathognomonic. This notwithstanding, an exact diagnosis cannot always be arrived at, for microscopic examination of exudate or blood from the swellings nearly always gives a negative result. When the disease runs an acute course, as in cattle and in sheep, or as in the intestinal form in the horse, diagnosis may be said to be im- possible during life. The rapid nature of the cases, and the closeness with which they may simulate other conditions— e.j., acute pulmonary conges- tion in cattle, apoplexy in sheep, and acute enteritis or intestinal twist in horses-^absolutely prevent any definite opinion being given. At the same time, when, on any particular farm or pasture, a case has once occurred, and has been diagnosed by unequivocal methods, and when other suspicious cases follow in its train, then the veterinary surgeon is * Veterinarian, vol. Ixix., p. 65. t Vide Journal of Comparative Pathology and Therapeutics, vol. xix., p. 247. ANTHRAX 39 able accurately to base an opinion on the clinical symptoms. This particularly applies to suddenly occurring and rapidly fatal cases of apparent pulmonary congestion in cattle and sheep on known anthrax- infested pastures, and to equally sudden and fatal attacks of apparent twist or apparent pulmonary congestion in horses in like infected areas. DIFFERENTIAL DIAGNOSIS. In Cattle. — ^Anthrax in cattle may be confused with cases of poison- ing by narcotic or acrid-narcotic 'principles of vegetable origin — e.g., celandine, yew, cake manufactured from the husk of the castor-oil seed, colchicum, ergot, hemlock, and many others. In such instances it is not usual that a diagnosis is made of the first case. The first death is, perhaps, shown by the microscopic examination of the blood and the subsequent post-mortem not to be anthrax. In possession of this nega- tive evidence, the veterinary surgeon is able to proceed, and, should further cases occur, is led by their history — by the connection between the symptoms and the food taken ; by the simultaneous sickness of many animals, without demonstrable contagion ; and by the compUcation of gastric and nervous symptoms — ^to look farther afield.* Death from lightning-stroke, quarter-iU, cerebral apoplexy, and acute pulmonary congestion, may also simulate anthrax. In the maia, diag- nosis in these cases also rests on proving the absence in the blood of the Bacillus amthrads, together with such evidence of a cUnical nature as each case affords. Particularly should quarter-iU be differentiated by the presence of the black-quarter tumour. The characteristic crackle and feather-hke feel of this lesion is almost unmistakable, and are further dealt with in the chapter relating to that disease. Moreover, smears taken from the incised quarter-ill muscle may be easily distin- guished bacteriologically from anthrax. In death from lightning-stroTce, too, there is usually evidence of superficial singeing of the coat, generally commencing at some high position — e.gr., the tips of the ears, base of horns, or top of lumbar region — and traceable down one or more of the limbs to the horn of the feet. Additional evidence in these cases is also often found in the fact that the animal is nearly always found with a tuft of grass held tightly between the incisor teeth — ^just proof that death -vras instantaneous and the animal in a fair state of health when taken. The malignant oedema bacilli rapidly appearing in the blood in these cases must be differentiated from those of anthrax by the charac- teristics already, given (p. 35). * Vide "Poisoning of Cattle by Common Celandine," Journal of Comparative Pathology and Therapeutics, vol. xvi., p. 367; and "Toxic Gastro-Enteritis," "Veterinary Pathology" (Friedberger and Frohner), vol. ii., p. 179 (1906 edition). 40 SYSTEM OF VETERINARY MEDICINE In Horaes. — ^We have already pointed out that anthrax in the horse may be mistaken for twist of the intestines and for acute congestion of the lungs. It may also be confused with other septicsemic conditions, more particularly furfura hcemorrhaigica, especially if in the latter instance the swelUngs of this" disease make their appearance in the region of the throat and neck. Here, again, diagnosis must entirely depend on a search for the bacilli of anthrax in the blood. In the case of purpura, however, a little help in diagnosis is furnished by the character and position of the swellings during life. Unlike those of anthrax, they tend to affect various parts of the body, more especially those parts that are dependent, not confining themselves to the throat and chest, but appear- ing in several positions rapidly and simultaneously. Moreover, the swelhngs in purpura show a much more decided tendency to become gangrenous, particularly where there is sHght pressure from such articles as the noseband of the halter or from the surcingle holding the rug. A further point of differentiation, too, is the fact that in purpura there is very often the discharge of a clear serous exudate from the skin in the bends of the hocks and in the hollows of the heels, with, later, gangrene and exfoUation of the surface layers of the skii^ in those positions. In differentiating equine anthrax from deatlj from lightniag-stroke the same search for marks of siageing must be made as in the case of cattle ; while in this, and in death from equally suddein cause while the animal is in jpossession of full health, the same care must be taken as in cattle to distinguish between the bacilli of mahgnant oedema and those of anthrax. A disease which very closely simulates anthrax cHnically is Sotnih African horse sickness-^so much so that it was at one time actually thought to be anthrax. Differentiation, however, is easy. If fresh,' the blood in South African horse sickness shows no bacteria of any kind, and jdelds nothing on culture. Moreover, points of differentiation are found as follows : That South African horse sickness appears at the end of the South African summer, and is extremely rare in winter; that the disease is peculiar to equines ; and that the spleen in horse sickness is unchanged. In Sheep.— The conditions with which anthrax may be confused in the sheep are mahgnant cedema, braxy, and louping-ill. Again, diag- nosis will depend on a microscopic examination of the blood for the bacilU, followed, if necessary, by cultivation or inoculation methods in the laboratory. In Pigs.— In these animals the appearance of the throat swelling is so characteristic as to be diagnostic, for, so far as is yet known, there is ANTHRAX 41 no other disease of pigs in wMcli this swelKng occurs. If, after death, verification of the diagnosis by demonstrating the bacilli is deemed necessary, then it mnst be remembered that the spleen and the blood contain but few of them, and that it may be further necessary to proceed to examination of sections from the glands a'bout the throat. According to Stockman,* " a fairly common lesion in pigs, and one of great diag- nostic value, is the presence of necrotic areas on the mucous membrane of the pharynx. These vary in size, but are commonly as large as a shiUing. The centre is dark, almost black in colour, slightly raised, and the edges are level with the mucous membrane. There is seldom any difficulty in finding anthrax bacilU in preparations made from these areas." PROGNOSIS. While in the course of an outbreak cases of spontaneous recovery may, and no doubt do, occur, the prognosis in anthrax must always be grave. The average mortality ranges from 70 per cent, to as high as 100 per cent., and once symptoms of any gravity set in, then death invariably results. PROPHYLAXIS. If we except protective inoculation, which is dealt with in the follow- ing section, then the most important prophylactic measure is the thorough - destruction of the anthrax-infected carcass. This may be done either by deep burial or by cremation. In the former case the Board of Agri- culture's regulations direct that the carcass be buried intact at a depth of not less than 6 feet below the surface of the earth, and with a layer of lime not less than 1 foot deep both beneath and above it. They further direct that such burial should take place in a spot to which animals have not access, removed from any dwelling-house, and at such a distance from any well or watercourse as wiU preclude any risk of contamination of the water therein. If cremation is decided on — ^and it is undoubtedly the most effectual method — ^then it is conveniently carried out by burning the carcass over a cross-trench.f i.* Journal of Comparative Pathology and Therapeutics, June, 1911. ^^if Cremation of Anthrax-Infected Carcasses. — As the veterinary surgeon may be ealled upon to advise regarding this, we quote here the description of the method given by General Tred Smith in his " Veterinary Hygiene " : " I use a trench dug in the form of a cross about | foot deep in the centre, and gradually becoming shallower as it reaches the surface of the soil. It is 7 feet long each way, by £ foot wide, and the earth Ijaken out of the trench is thrown in the right angles formed by it ; on this earth the wood is placed. If two pieces of stout iron can be obtained to place the wood on, so much the better. A layer of big 42 SYSTEM OF VETERINARY MEDICINE lu either case, care should be taken to collect the last excreta passed by the animal, the spilled discharges from the natural orifices, and any- infected portion of fseces or stable litter, in order to bury or to burn with the carcass. These methods should each of them be followed by a rigid disinfec- tion of the surroundings, and for this purpose either a 1 in 1,000 solu- tion of perchloride of mercury or a 4 per cent, solution of creolin is suitable. Should the cases arise in the centre of some large town, and neither of these methods be immediately available, then the carcass must be moved to some knacker's yard or other suitable place, and there either burned as above described, or subjected to compressed steam sufficiently long to break up all the softer structures. The bones should afterwards be destroyed. Before moving the carcass, the natural orifices must be plugged with tow or cotton-wool steeped in some reliable germicide, and a strict disinfection of the surroundings and conveyances used, should be afterwards carried out. Anthrax in Dogs, Cats, and Faimyaid Poultry. — Although ordinarily the carnivora and birds are not easily infected, the possibility of anthrax occurring in these animals must not be overlooked by the veterinarian. Dogs have been known to contract anthrax by ingestion of anthrax- infected flesh, as also have fowls. It is important, therefore, to remember this when disposing of the larger animals dead of the disease. PROTECTIVE INOCULATION. In this country, for reasons which we shall afterwards discuss, pro- tective inoculation against anthrax has not been largely attempted. Elsewhere, however, in nearly every country in Europe, notably Germany and France, and in America (Argentina and Uruguay), these inoculations have been carried out on a large scale. The practitioner should there- fore become acquainted with the methods employed and the technique of the operation. Practically, there are two methods which have come into prominence. The one consists in subcutaneous injections of attenuated anthrax wood comes first ; then the trunk, which has had all the limbs and viscera removed ; next more wood, and on this are placed the limbs, covered by wood ; and, lastly, the viscera, also well covered with wood. The pile is then set fire to, and the body of a horse can in this way be readily consumed in five or six hours. ... If the body be placed whole on the fire, it will take about twelve hours to consume." To this we would add that in districts where wood is scarce coal may be added to the fire with advantage. The method of cremation is expensive and tedious (careful turmng being required during consumption of the carcass), but, as we have mentioned m the text, is certainly the most effectual. ANTHRAX 43 cultures ; the other in the simultaneous injection of an attenuated culture and an anti-anthrax serum. We will take first tJie method of injecting attenuated cultures. It is now well known that the virulence of an anthrax culture may be reduced by one of several means. Touissant, for instance, first showed that the virulence of anthrax blood was lessened by the application of heat. Attenuation of the virus was also obtained by cultivating the bacillus in media containiag weak antiseptics (Chamberland and Roux) ; again, by the application of heat (Pasteur and Chauveau) ; by growing in com- pressed oxygen (Chauveau) ; by cultivating the organism in the blood or serum of animals that are immune— e.g^., white rats, frogs. There are still other methods, and the most of them consist in cul- tivating the organism in conditions slightly unfavourable to its growth. In obtaining the necessary attenuation, whichever method is adopted has for its primary object the prevention of spore formation. The method which has been found the most suitable, and has therefore become general, is that of heating. This is associated with the name of Pasteur. By cultivating anthrax bacilli in the presence of oxygen at a tem- perature of from 42° to 43° C, Pasteur found that they ceased to form spores, although still multipljdng by fission. He further found that varying degrees of attenuation were to be obtained proportionate to the length of incubation. The longer the cultures were subjected to the temperature above stated, the greater the degree of attenuation. By then inoculating laboratory animals with the attenuated cultures, two vaccines were arrived at suitable for the protective inoculation of the larget animals. The First Vaccine (the weaker) consists of a bouillon culture of non- sporulating anthrax bacilli attenuated by cultivation for twenty-four days at a temperature of 42'5° C. This, when injected, must be fatal to mice, but not to guinea-pigs. The Second Vaccine (the stronger) is a similar cultivation incubated at the same temperature, but for only twelve to fourteen days. When injected, this should be fatal to both mice and guinea-pigs, but not to rabbits. The animal to be protected is then inoculated with the first or weaker vaccine. Ten to fourteen days later it is again inoculated, this time with the second or stronger vaccine. Immunity is said to be estabhshed in ten days to a month after the second injection, and to last for one year. Instructions are generally issued with each lot of vaccine sent out, and the operator is directed to make the injections subcutaneously behind 44 SYSTEM OF VETERINARY MEDICINE the shoulder in the ox, and in horses and mules in the region of the neck. He is further instructed to make the first injection on one side of the animal, and the second injection on the other. The dose of each vaccine for horses, cattle, and mules is 1 to 4 c.c„ and for sheep and goats 1 to 8 c.c. The injection should be made with a small Pravaz syringe supplied v for the purpose. The second method — viz., that of injecting simultaneously an attenuated culture and an anti-anthrax serum — has been largely employed by Sobern- heim. To obtain the necessary serum, animals already immunised by the Pasteur vaccines are taken, and further injected with large quantities ■ of a virulent culture. Their blood then yields a serum wMch shows marked prophylactic and curative properties against anthrax when injected into rabbits. In other words, there has been obtained an anti-anthrax serum with marked bacteriolytic properties. The serum thus obtained is injected in a dose of 10 c.c. into one side of the animal to be protected, while into the other side is injected at the same time an attenuated culture of about the same strength as Pasteur's second vaccine. Both of these methods are successful in conferring immunity. Against that of Pasteur it has been urged by Koch that, while it protects against inoculated anthrax, it gives no immunity from natural infection by way of the intestinal tract. If this be so, then no stronger objection can be raised against its use in veterinary practice. Further, it may with truth be objected against this method that losses occur from the vaccination itself, and that these losses are sometimes heavy. It is in this way : While the losses, calculated on a large number of inoculations, are only 1 to 2 per cent., yet these same losses from inoculations on a particular farm may be as high as 10 per cent. Therefore, so far as Great Britain is concerned at any rate, the losses from inoculation itseK may exceed the average natural loss from the disease. In other words, the Pasteurian inoculation is not to be advised except in those instances where the disease in a district is stationary, and where there are regular and heavy losses from it.* The method of Sobernheim appears to be free from this element of danger. Moreover, if we take Sobernheim's own conclusions, which con- clusions appear to be well founded, it possesses other advantages. It is quickly effective, and has not to be repeated. It protects from infec- * According to Stockman, observations on several millions of cattle in various parts of the world, submitted to the Pasteur method of preventive jnoculation showed that accidents occurred in about 0-5 per cent, of the inoculated, taken all round. — Ed. ANTHRAX 45 tion by way of the intestinal tract, and a more lasting immunity is conferred. Sobemteim's pubUshed results, particularly of the inoculations in Argentina and Uruguay, certainly appear to offer proof of the efficiency of this simultaneous method of iaoculation against anthrax. Although carried out on nearly 300,000 animals, it was not in itself productive of any loss, and, as shown by statistics, served to bring about the almost complete disappearance of cases of anthrax. In districts, therefore, where anthrax is constantly present, and where the losses from the disease exceed 2 per cent., the simultaneous method of inoculation may be advised. For the very reason, however, that iu Great Britain anthrax is not the scourge it is in a hotter climate, it is doubtful whether any method of protective inoculation, with its expense and attendant risks, is warranted. The ordinary prophylactic measures may serve the necessary purposes. TREATIOENT. Having regard to the rapidly fatal course of anthrax in the majority of the domesticated animals, it may be said at once that any ordinary treatnjent of the disease may be looked upon as useless. By " ordinary treatment " we here mean the administration of mediciaes. In passing, however, it is interesting to note that improvement and quick recovery has been reported after the administration of 50 to 200 grammes of creolin (Meier), and that such agents as perchloride of mercury (sub- cutaneous injection), carbolic acid and salicylic acid in 10 to 15 gramme doses, Lugol's solution in 2-ounce doses, chlorine, arsenic, phosphorus, hydrochloric acid, and ammonia, have all been recommended. Recovery under treatment such as this, however, cannot fairly be attributed to the therapeutic measures alone. Far more likely is it to be one of the spontaneous recoveries that careful temperature records have shown to occur during the course of an outbreak. The use of a reliable anti-anthrax serum, however, would appear to be indicated. Sobemheim has shown that animals inoculated with virulent anthrax cultures have successfully withstood this inoculation if subsequently injected with large doses of an anti-anthrax serum ; that, therefore, the serum may be regarded as curative. With this in view, such cases as run a protracted course, and thereby offer opportunity to the veterinarian — e.g., cases of the disease in the horse — may yet be proved to be amenable to a bacteriolytic serum. Stockman states that if accidents threaten to occur from preventive inoculation, they can be avoided to a large extent by administering 46 SYSTEM OF VETERINARY MEDICINE a dose of anti-anthrax serum. He also advises tlie use of the serum in cases where an animal has died of anthrax amongst other animals, and its blood has been spilt. The injection is then carried out on the re- maining animals ; also in cases where any in-contact animals show an abnormally high temperature the serum is indicated. The immunity from serum is said to last for about ten days. It can only be of use in cases where the blood-stream is not invaded by the bacilli. NOTE ON ANTHRAX IN WILD ANIMALS IN A STATE OF CAPTIVITY. In the Veterinary Record of February 25, 1911, an outbreak of anthrax amongst wild animals in a menagerie is reported by Mr. F. Somers, M.R.C.V.S. The following animals died from the disease — ^viz., two pumas, one lioness, one leopard, two racoons, one coypu, one English badger, one ant-eater, and two Polar bears. A vulture also succumbed to the disease. The following showed marked s3rmptoms of anthrax, and recovered — viz., two lions, two leopards, one Polar bear, and one or two smaller animals. — ^Editor. NOTE ON GLOSS-ANTHEAX. In many respects the term " gloss-anthrax " is an unfortunate one, and save for the fact that it has crept into somewhat general use no mention would have been made of it in connection with the foregoing chapter. Simply it signifies anthrax . affecting the tongue ; and, inasmuch as we know that the tongue sometimes becomes the seat of anthrax lesions — notably in outbreaks among the carnivora and in pigs — that at first sight would appear justification enough for the retention of the term in our nomenclature. Unfortunately, however, there is no reason to doubt that gloss-anthrax is far more often used in recording not cases of anthrax, but those conditions which only simulate it. For instance, the disease affecting cattle in this country, and known as " hawks," " blain," or "gloss-anthrax," very often appears much more like urticaria than anything else, in support of which statement we would point to the quick rise of the swelling, its equally rapid decline, the almost constant failure of the lesion to spread far from the seat of inoculation, and to the very frequent rapid recovery of the patient. If such a swelling were due to a local infection with anthrax, par- ticularly as it occurs in an animal so susceptible to that disease as the ox, then one would most certainly expect it to spread with extreme rapidity, and the condition itself to show a high death-rate. In short, that the disease is more or less benign is opposed to the fact of its being anthrax at all. Again, from continental writings we are able to judge that the term " gloss- anthrax " is used in reference to a condition in which buUsB appear on the tongue and buccal mucous membranes, which bullae break and discharge a stinking fluid. While it is probable, especially in the case of the carnivora, that such a condition may indio&te an attack of anthrax, it is far from being equally probable in the case of the herbivora. Malignant oedema, hsemorrhagie septicsemia, and ordinary cases of ulcerative stomatitis may give rise to somewhat similar lesions, and a diagnosis of anthrax in such a case is very wide of the mark. With advantage to everyone it seems that the term " gloss-anthrax " might be conveniently dropped. In dealing with our case it would be better to say simply that we have " anthrax," making that statement dependent on demonstrating the anthrax bacilli in the blood or discharges ; and then, if lesions occur in the tongue, simply to *ay so, J^uc]^ ppufusion would thereby be saved. — H, C, K. BLAGK-QUARTER Synonyms. — ^Black-leg ; Quarter-ill ; Symptomatic anthrax ; Emphy- sematous anthrax ; Struck ; Strike ; Carbuncular erysipelas ; Merylen ; Felon, etc. French : Charbon symptomatique ; Charbon bacterien. German : Eauschbrand. Definition. — It is an acute specific enzootic and infectious disease of the ox, and occasionally of sheep, characterised by the appearance of a rapidly increasing emphysematous swelling, containing black extra- vasated blood and gases, in the region of the quarter, thigh, shoulder, neck, trunk, or elsewhere. History. — The disease has been known since the dawn of veterinary science, and in the early days was thought to be' a form of anhrtax. Charbert, in 1790, appears to have been the first to clinically distinguish the disease from anthrax. This opinion was strongly supported and amplified in later years by WallrafE and Pfisterer. In 1876 Bollinger, and subsequently Feser, revealed the presence of motile rods in the crepitant tumours, which they considered specific. They succeeded in trans- mitting the disease to cattle and sheep by inoculating them with virulent material from the lesions. In 1879 Arloiag, Cornevin, and Thomas investigated the disease, carryiag out experiments to distinguish it from anthrax, and describing the principal characters of its bacillus ; they also devised a method of vaccination, which they published in 1884. More recently the important work of Kitasato, E. Roux, Duenschmann, and Kitt, has thrown a powerful light on the biological properties of the bacillus, and on the method of producing artificial immunity. GBOaRAPHICAL DISTRIBUTION. The disease occurs in every country, but it has a very uneven or regional ' distribution. In large areas it is quite unknown. In some districts it may be found on certain farms, and not on others ; while on -some farms it is well kaown that particular fields are notoriously infected. 47 48 SYSTEM OF VETERINARY MEDICINE It is especially prevalent in old permanent pastures and moorland, and tends to disappear with drainage and cultivation. It is reported to be the all-prevailing cattle disease in Poito Rico, a country where anthrax is unknown. It is scheduled as a contagious disease in Austria, Belgium, France, India, Italy, Norway, Sweden, and Switzerland. The statistics from these countries show that the disease has no distinct seasonal occurrence, the outbreaks being distributed in a fairly even manner all the year round. ANIMALS SUSCEPTIBLE. The vast majority of naturally occurring cases are seen in young cattle, ranging from three months to two years old, although cases are occasionally met with in cattle up to four years old. Cases of the disease in a three-day-old calf and a six- year-old cow have been recorded by Strebel and Foster respectively. The individual susceptibility of cattle seems to vary very much. Cases are occasionally met with in the sheep. It is, however, quite possible that a proportion of naturally occurring cases in this animal are overlooked or confounded with other diseases, owing to the absence of veterinary inquiry. As 'tested by experimental inoculation, the sheep is much more susceptible than the ox. The guinea-pig is susceptible by inoculation ; very young guinea- pigs are, however, less susceptible than old ones. Cases have also been observed in the reindeer, camel, and young buffalo. The horse, dog, ^ig, cat, rabbit, and man, are regarded as virtually immune, although cases of the disease are recorded in the horse by Ganter, Liebold, Leon- hardt, and others, and in the pig by Marek and Battistini (Friedberger and Frohner). PORTALS OF INFECTION. Experimentally, endermic inoculation generally fails, but the sub- cutaneous and intramuscular methods of infection generally yield positive results, especially in the casfe of the subcutaneous method, if the part selected is rich in loose connective tissue. Experimental infection by the mouth is rarely, if ever, successful, and it is uncertain whether naturally occurring cases are infected by this channel or not. On the other hand, there is seldom, if ever, a cutaneous wound found associated with the lesion in natural cases. Notwithstanding the almost insuperable diffi- culty of infecting by the mouth, it is still possible that infection does naturally take place by that portal. The explanation is probably that naturally occurring cases follow upon some defective alteration of the BLACK-QUAETBE 49 defences of the body, or a quickening influence on the bacillus, which enables the latter to enter the tissue from the alimentary canal. IMMUNITY. One attack of the disease is said to produce immunity, but as black- quarter is one of the most fg,tal diseases of the bovine species, our ex- perience in this matter is necessarily very limited. Old cattle hardly ever contract the disease, and seem to possess a natural immunity, which increases with age. Cases are not common in sucking calves, but they are not immune. Algerian cattle are said to possess a relatively high degree of resistance, and the Agro Eomano cattle, although very sus- ceptible to accidental infection, are reported to be refractory to experi- mental inoculation. ETIOLOGY. The essential cause of the disease is the invasion of the tissues of the body by the Black-quarter haciUus, which is also known as the Bacillus anthracis emphysematosa, Bacillus Ghauveii, Rausclibrand bacUlm, and the Bacillus sarcophysemaios hovis. BACTERIOLOGY. The bacillus, is a facultative parasite, living mainly a saprophytic existence in the soil, the vast number of outbreaks being of sporadic origin, due directly to a soil bacterium. The bacillus is motile and a strict anaerobe. It is chiefly a tissue parasite, confined to the lesions. In no animal is the disease of a septicsemic character, although in some cases in the ox it is possible to demonstrate baoiUi in the blood at the time of death. In the sheep, however, they are as a rule present at the time of death, and can be easily detected. The bacilli are also found in any effusions which may exist in the serous cavities. Sporulation does not take place in the living body, although the bacilli continue to multiply in the body for a considerable time after death, if the temperature is suitable, and the blood from a carcass may present a septiceemic picture some hours after death. 'The bacilli found in the blood and in very acute lesions at the time of death appear as slender rods, with rounded ends, measuring 3 to 6 microns in length, and about 0-5 to 1 micron in breadth. They stain uniformly throughout, and represent the actively multiplying form of the bacillus. In natural lesions, examined some time after dej-fch, bacilli of various shapes are found, and as a nile comparatively few of them are cylindrical or stain rainiformly. The majority are spindle or cigar shaped, and stain irregu- VOL. I. 50 SYSTEM OF VETEEINARY MEDICINE larly ; others, again, present the appearance of a tennis-racket, owing to the presence at one pole of the bacillus of a large oval spore. Another characteristic appearance is where two bacilli are joined to- gether, and, sporulating at opposite poles, resemble the outline of a pair of spectacles. The bacilli do not form filaments, although two or three may be often found joined together. , They stain well with methylene blue and the other basic aniline dyes, and also by the method of Claudius ; by Gram's method only when the process is greatly prolonged. In culture they behave as the strictest of anaerobes, giving off a gas composed chiefly of hydrogen, COg, and nitrogen, and producing a sour smell resembling that of rancid butter^ due to the formation of butyric acid. They grow at body temperature and in ordinary media, but Martin's broth appears to suit them best. The bacillus is possessed of great vitality. It may live indefinitely in deep stiff clay soils, owing to the absence of oxygen and light. It is not injured by putrefaction, and intense cold does not affect it. Ex- posure to a dry heat of 100° C. for twenty minutes cannot be trusted to destroy it, but boiling for that length of time proves fatal to it. It is destroyed by such agents as mercuric chloride {ru per cent.), salicyHc acid (2 per cent.), carbolic acid (2 per cent.), copper sulphate and boric acid (20 per cent.) ; while sulphuric acid, quicklime, chloride of zinc, alcoholic solution of carbolic acid, have given unsatisfactory results. The activity of the virus is increased by the addition of such agents as lactic acid, acetic acid, dilute alcohol. These, however, are supposed to act by preventing phagocytosis. The same effect can be produced by bruising the seat of inoculation before or after the operation. PERIOD OF INCUBATION. The period of incubation varies from one to five days, the average period being about two days, and, in exceptional cases, it may be reduced to a few hours. MORBID ANATOMY. There is usually an external emphysematous tumour seen in connec- tion with some of the large muscular areas. In most cases it is located in a limb, but it may be on the trunk or the neck. Decomposition sets in rapidly, so that th'e whole carcass rapidly becomes emphysematous, and a blood-coloured frothy discharge appears at the natural orifices. ' The skin over the tumour is sometimes dry and leathery, indicating a condition of dry gangrene ; when cut iiito, the affected muscular tissue BLACK-QUAETEE 51 is found soft and friable, and of a dark brownish or almost black colour, and surrounded by a blood-tinged exudate, which shows little tendency to coagulate. The centre of the affected muscular mass is abnormally dry and somewhat emphysematous, showing haemorrhages ; outside this central area there is usually a haemorrhagic zone saturated with blood- tinged exudate. The nearest lymphatic glands are enlarged and con- gested. Often there is a quantity of blood-tinged fluid in the peritoneal cavity, and occasionally also in the thoracic and pericardial cavities. The thoracic and abdominal viscera usually show no lesions, although haemorrhagic infiltration may be found in the heart, lungs, liver, kidneys, stomach, and bowels ; the spleen is seldom affected, and never enlarged. The muscular lesion gives off a rancid odour at first, which becomes highly offensive as putrefaction sets in. The extent to which the lesion becomes emphysematous is in proportion to the slowness of the disease, so that acute cases are cedematous, and not emphysematous. In sheep the lesion is often obscured by the fleece, but it sometimes happens in this animal that prior to death the wool is shed over the affected part, and a blood-tinged exudate exudes from the denuded sMn. The blood shows no pathological changes, and forms a clot of normal firmness. SYMPTOMS. The disease is swiftly established and of brief duration, natural cases occupying a period ranging from less than twenty-four hours to three days. Not infrequently it happens that the first intimation of an outbreak, even in herds under daily supervision, is revealed in the carcass of a victim. On the other hand, many cases present well-marked and characteristic symptoms ; the animal is observed to be dull, refuses food, stands apart from its comrades, with slightly elevated back and head carried low, presenting an anxious and dejected appearance. Muscular tremors and spasmodic movements of the head are noticed, if carefully looked for. The pulse and respiration are accelerated. The temperature rises to 104° or 105° F., and in acute cases runs up to 107° F. It should be noted, however, that from the observations of Schiitt Warringsholz, and Steinbuck, it is possible that cases may occur without any increase of temperature.* * With reference to the question of the temperature in black-quarter, Baldrey (Indian Veterinary Jcmrnal, 1911) recorded his observations on twenty-one oases of the disease .at Muktesar, and concluded "that in black-quarter there is usually at 52 SYSTEM OF VETEEINARY MEDICINE If the animal is made to move, lameness or stiffness is evident ; and on examination a swelling is noticed on the shoulder or hind-quarter, or some other part of the body. The swelling is quite commonly- found on the neck, chest, back, and loins, where it may not cause lameness, but a general stiffness. Occasionally it may appear in the palate and back of the tongue. It is never found below the knee or hock, owing to the denseness of the subcutaneous tissue in these regions. The swelling is at first somewhat cedematous, hot, and painful, and pits on pressure ; but, increasing rapidly, it becomes emphysematous, crepitating on pressure, and resonant on percussion. The skin covering the part becomes cold and leathery, indicating necrosis and the advent of gangrene. When incised, no pain is evinced, and a dark frothy fluid escapes, giving off a sour smell. As the disease progresses the symptoms become aggravated, constipation' is present, the pulse becomes weak and imperceptible ; the temperature may fall or become sub- normal before death. The victim refuses to move or rise, and dies in an almost comatose condition. Brain symptoms are seldom or never noticed. Death usually results within twenty-four hours ; but if the disease is generalised, it may take place in a few hours, while prolonged cases may linger for two or three PROGNOSIS. The disease is highly fatal, fully 95 per cent, of the victims succumb. Recoveries in vaccinated calves have recently been recorded by Hewetson and Roberts. Galtier states recoveries are frequent in Algeria, and rare in France. Tisserand puts the recoveries in the latter country at about 2 per cent. some period in the course of the disease a high temperature, but to the ordinary chnioian the absence of this would not be remarkable." He pointed out that if the temperature be taken every hour it is very possible that every case would show a high temperature at some period in the course of the disease. . The temperature varies from hour to hour, as shown by three of the cases in which it was taken every two hours. It commences to fall very rapidly after reaching its highest point, and becomes subnormal just before death, in some cases desoencSng to even 94° F. In the very acute cases the marked rise in temperature may be overlooked, as coUapse quicMy occurs and the temperature rapidly runs down until death takes place. In the more chronic cases, extending over a space of from two to three days, a highly febrile period is always observed. The rational deduction from the observations appears to be that black-quarter should be regarded as a febrUe disease, but that the rise of temperature may be of such short duration that it is likely to be overlooked, and cannot be regarded as of any value in the diagnosis of the affection. — Ed. BLACK-QUARTER 53 DIFFERENTIAL DIAGNOSIS. Antlirax and malignant oedema are the only diseases with which it is likely to be conf omided. - From Anthrax. — ^Black-quarter is distinguished from anthrax— 1. Cliniccdly, by the presence of the emphysematous crepitating tumour — a lesion which is never met with in anthrax. 2. On post-mortem, the presence of this tumour, with its characteristic conditions and peculiar sour odour, makes the diagnosis certain. Unlike anthrax, the spleen is never enlarged in black-quarter, and the blood appears unaltered to the naked eye, and forms a clot of normal firmness. 3. BacteriologicaUy, the two diseases are distinguished by the mor- phology of their causal organisms, the cultural behaviour of these organisms, and their effect upon the ordinary experimental animals,, as set forth in the following table : Black- QuAETEK. Anthrax. Short thick bacillus, with rounded A longer bacillus of a uniform thick- ends, very motile, does not form fila- ness with square or cup-shaped ends, ments, often exhibiting a spore which non-motile, forming filaments, and sur- gives it a club or spindle shaped appear- rounded in fresh specimens by an en- anoe. It is an anaerobe, and mainly a velope or capsule. It is an aerobe, and tissue-parasite confined to the lesion. chiefly a blood - parasite invading the whole system. In culture a strict anaerobe, producing In ciilture an aerobe, does not produce gas and evolving a peculiar odour. gas or give off an offensive odour ; pro- duces characteristic growths in bouiUon, gelatine, and agar. It is not destroyed by putrefaction. It is rapidly destroyed by putrefac- tion. Rabbit immune; guinea-pig suscep- Both rabbit and guinea-pig very sus- tible. ceptible. Impossible to infect by cutaneous in- Easy to infect by cutaneous inooula- oculation. tion. Intravenous inoculation produces only Intravenous inoculation always fatal, slight disturbance with subsequent im- munity. Subcutaneous inoculation causes ex- Subcutaneous inoculation is followed tensive swelling at seat of inoculation. by only a sUght or negative reaction at seat of inoculation. According to Hamilton, the bacillus of Braxy is distinguished from the black-quarter bacillus by its comparatively small size and delicacy of contour. From Malignant (Edema. — The disease is distinguished from malig- nant oedema by the presence of the characteristic muscular lesion, with its accompanjdng sour odour. The black-quarter bacilli are actively motile, and occur singly or in very short filaments, while the malignant oedema bacilli are only slightly motile, and form characteristic long filaments. In culture the black-quarter bacilli give off a peculiar odour. 54 SYSTEM OF VETERINAEY MEDICINE while the malignant cedema bacilli produce a putrid odour. Young cattle are susceptible to black- quarter, but almost immune to maligriant oedema. Horses, swine, dogs, rabbits, pigeons, and chickens, on the other hand, are susceptible to natural or experimental infection with the latter disease, but are practically immune to the former. Black-quarter is restricted to locality, while maHgnant cedema is universal. A disease somewhat similar to black-quarter is described by Carl and Albrecht as occurring in aged cows two to four days after parturition. It is characterised by tumefaction of the external genitals, extendiag to the sacrum, thighs, and back; the swelling is emphysematous and crepitates. The mucous membrane of the uterus is also involved. This disease has been erroneously termed "parturient black-leg," but in reahty, as demonstrated by Carl, it is caused by the bacillus of malignant oedema, and the'diagnosis must be made by bacteriological investigation. From Mechanical Emphysema. — Occasionally it may be found necessary to distinguish between black-quarter and mechanical emphysema of the skin arising from wounds in the region of the neck, sternum, and elbow, or injuries to the trachea or oesophagus. In this lesion, however, there is comj)lete absence of inflammatory changes in the tumour, and puncture of it quickly reveals its true nature. TREATMENT. Black-quarter is such a fatal disease, and runs so very acute a course, that treatment is generally out of the question. If a case is discovered , early, treatment may be attempted by freely incising the local lesion and injecting strong antiseptics into the subcutaneous tissue. Internal antiseptics might also be tried, but as a rule treatment is useless. PROPHYLAXIS. The agriculturist can do much to banish the disease by improved farming, draining, and liming of the infected land. Young susceptible animals should not be grazed, on lands known to be badly infected, and young animals in poor condition should not be suddenly put on rich pasture. Affected animals should be immediately isolated and destroyed, the carcass being cremated, or buried deeply in lime. The carcass should be buried in its skin in sonie convenient place to which animals will not have access, and at a safe distance from any well or watercourse. The place where the carcass lay should be thoroughly disinfected. In the case of infected premises the buildings should be thoroughly cleansed and disinfected, all excreta and litter being burnt, or disinfected and buried. BLACK-QUARTER 55 In the past, various measures were practised as a means of preventing the disease — such as bleeding, purging, setoning, and the administration of drugs, such as carbolic acid ; but their efficiency was doubtful, and they have been almost entirely superseded in recent years by various methods of vaccination, which have given much better results. VACCINATION. It is possible to confer a high degree of immunity on young cattle by several jnethods of protective inoculation, two of which, at least, have been practised largely— viz., (1) Arlding's Method ; (2) Kitfs Method. Arloing's Method. — In Arloing's method two vaccines of different virulence are used, and are prepared as follows : the affected muscular tissue from the tumour of an experimental case is cut out with sterile instruments immediately after death, dried, and powdered. The dry powder is then mixed with sterile water, to convert it into a uniform thick paste, and placed in an incubator for seven hours at a temperature of 100° C. for the first vaccine, and for the same time at a temperature of 90° C. for the second vaccine. After this treatment the material comes out of the incubator in the form of perfectly dry, brittle crusts, which, when pulverised, are fit for use. The dose of either vaccine for a yearling is 1 centigramme. The material is generally put up in vials containing 1 decigramme each, and at the time of inoculation the con- tents of each tube have to be ground up with 10 c.c. of sterile water. Bach c.c. of the mixture will then contain one dose. The ordinary seat of inoculation is the under-surface of the tail; the first vaccine being injected quite close to the tip, and the second a few- inches higher up, after an interval of about ten days. The operation is attended with some difficulty, owing to the density of the subcutaneous tissue of the part. The operation is sometimes modified by omitting the first vaccine, and by operating behind the shoulder ; but statistics tend to show that these modifications are attended with greater risk to the animal. Rial's Method. — In Kitt's method a single vaccine only is employed, and it is usually inj ected at the shoulder. The preparation of this vaccine differs from Arloing's in that the virulent muscle-powder is subjected to moist heat in a steam sterilizer for six hours, at a temperature of 97° to 100° C. The dose of this vaccine is a decigramme. The only advantage of Kitt's method is that immunity is conferred at one operation. On the other hand, the double vaccine method, although more troublesome, is less risky for the animal, and invokes a more lasting immunity. 56 SYSTEM OF VBTERINlRY MEDICINE Both Arloing's and Kitt's vaccines are put up commercially in the form of strings, pellets, and powders, by veterinary laboratories and drug companies, and are used extensively throughout the world. Care should be taken when operating to prevent bruising or crushing of the tissues in the vicinity of the seat of inoculation. Immunity is said to follow the application of these vaccines in about a week's time, and last for about nine to twelve months. As to the proper age and time of year to vaccinate, much must depend on local circumstances. In this country calves are generally operated on in the spring or autumn, about the age of from four to seven months ; but the operation can be done at almost any age or season, and should be repeated annually on young bovines in districts where the disease is prevalent. On the other hand, it is, generally speaking, not advisable to carry out vaccination on farms where the disease is only an occasional visitor. The losses attributed to the operation are very few, when calculated on the large number operated on, but are very unequally divided, amount- ing in some instances to 5 or 10 per cent., or more, in a small herd. Senm Vaccine. — Kitt was the first to introduce this method. The serum is now got from horses which have been hyper-immunised by repeated injections of black-quarter cultures. A 10 to 20 c.c. dose gives a high immunity, which is only of a passive character, lasting about one week. Serum and Virus Method (introduced in France by Leclainche and Vall6e). — In this method the animal first receives 10 to 30 c.c. of a pro- tective serum, and about one week afterwards 1 c.c. of a sporulating broth culture, which has been heated for three hours at 70° C. The object of the serum is to set up a passive immunity which will abolish the risk involved in applying the virus. This is said to be the safest of all methods, but is open to the risk that at the time the virus is in- jected the passive immunity is all-powerful, and therefore the chance of securing a lasting immunity is somewhat doubtful. Immunity can also be established by the intravenous injection of a small quantity of virus, but the risk attending this method debars it from practical application. PUBLIC HEALTH. Although the disease is not transmissible to man, and the flesh not injurious to health, still, as it readily decomposes, and even when pre- served develops a rancid odour, it should be invariably condemned as unfit for food. BLACK-QUAETEE, 57 BLACK-QUARTER IN SHEEP. As already remarked, sheep are more susceptible to experimental inoculation of black-quarter than cattle, but outbreaks of the disease in these animals are not often recorded. It is, however, probable that the disease may be overlooked or mistaken for other affections of the sheep. McFadyean has met with several instances where on certain farms serious losses have occurred from black-quarter in sheep.* He points out that in sheep the susceptibihfcy to the disease persists through- out life, thus differing from cattle, in which the affection is rather un- common in animals over two years of age, and very rare in adult cattle. According to Stockman, lesions of the skeletal muscles may be very sKght or even absent in sheep dead of black-quarter. Cavef investigated an outbreak of the disease that occurred most commonly on the Eomney Marsh, and also in other marshlands of Kent, and occasionally in upland districts. The disease was locally known as " struck," and various theories were held by the flock-owners as to its true nature. Sheep of all ages were attacked, and, as in the case of cattle, it was generally found that the best animals in the flock were most susceptible. Several cases occurred in pregnant ewes — sixty of these dying in a few weeks out of a flock of 200 ; these fatalities occurring in a district at some elevation above sea-level, where the loss from the disease was said to be usually slight. The lesions found were identical with those of black-quarter in cattle, and microscopical examinations of the exudate from the diseased muscles showed the presence of the black-quarter bacillus ; this organism was also found in the blood and in the pleural and peritpneal fluids. The diagnosis was confirmed by McFadyean. The course of the disease was very rapid, and the animal was generally foimd dead in the pasture, without any history of previous illness ; in some instances the animals staggered, fell to the ground, and died in a few minutes. More rarely death was delayed for some hours ; the animal stood with all four feet close together, its back arched, and its respirations greatly accelerated; a frothy, blood-stained dis- charge issued from the nostrils, and diarrhoea, with blood-stained faeces, was also present. The animal was made to move with diflGiculty, and showed considerable stiffness of the limbs. It soon fell to the ground, and quickly died. It was not decided whether any marked swellings were present during life, as, in consequence of the rapid onset of the * Vide Journal of Comparative Pathology and Therapeutics, 1901. t The Journal of Agricultural Science, vol. i., part ii., May, 1905. 58 systeJm of vbteeinaey medicine disease, the suddenness of deatli, and the thickness of the wool, this point was difficult to determine. Inoculation of a healthy sheep with the serum obtained from the diseased muscle of an affected animal, the fluid being injected deeply into the muscles of the thigh, caused death within twelve to fourteen hours after the inoculation. The inoculated animal presented all the appearances of an ordinary case of the disease, and microscopical examina- tion of the exudate showed the presence of numerous black-quarter bacilli. Cave conducted numerous experiments with a view to immunising sheep against black-quarter, the vaccines used being those employed for a similar purpose in cattle. He arrived at the following conclusions : " 1. That the double vaccine A undoubtedly renders sheep strongly immune against black-quarter. " 2. That the double vaccine A is uncertain in its action, and under certain conditions may be highly dajngerous when used in the field. " 3. That a single vaccine may be powerful enough to kill and, may yet fail to give a lasting immunity to those animals which survive the inoculations. " 4. That none of the vaccines tried ia these experiments have proved entirely satisfactory, although enough has been done to show that the loss from ' struck ' sheep could be greatly diminished by pro- tective inoculation, if a safe and efficient vaccine were available. " It'is possible that more favourable results will be obtained in the future by the use of vaccines specially prepared for sheep." GLANDERS By WILLIAM HUNTING, RR.C.V.S., Consulting Veterinary Surgeon to the London County Council. Synonyms.— Equinia ; Farcy. Latin : Malleus. French : Morve. German : Eotz. Definition.— Glanders is a specific disease due to the growth and development within the animal body of a micro-organism, the Bacillus mallei. The disease is characterised by morbid changes affecting the skin, mucous membranes, lungs, lymphatic glands, and other organs. These changes vary according to the activity and position of the causal organism, and are modified by the health, age, and condition of the infected animal. HISTORY. Glanders was recognised by Hippocrates about 450 B.C., and by Aristotle a century later. It was described by Apsyrtus in the fourth century of our era, and by Vegetius in the fifth. In 1618 the celebrated Italian anatomist Euini described glanders, and declared it to be " a general disease and incurable." No writer- of the seventeenth century expressed any clear ideas about the nature of glanders, but they all seem to have observed that it was con- tagious, and it would have been well for horse-owners had this simple experience not been upset by theories of less acute observers. In the eighteenth century some progress was made, and a French veterinarian, Gaspard de Saunier, 1734, recognised glanders as " highly contagious," and traced its transmission through harness, water-troughs, pails, and mangers. Unfortunately, in 1749, Lafosse, Senior Farrier to the King, communicated to the French Eoyal Academy of Medicine "A Memoir of the Glanders ia Horses," in which he argued that the seat of the disease was in the nasal cavities, and he concluded " that 69 60 SYSTEM OF VETERINARY MEDICINE glanders does not depend upon a general distemper of the blood, but is really and truly a simple and local malady." For lialf a century this non-contagion theory obtained general acceptance, although a few eminent veterinarians attempted to refute it. Lafosse's opinions gained weight from his prominent position, and their wide acceptance was disastrous to the adoption of any rational preventive measures. Bourgelat, the founder of modern veterinary science, who established the schools at Lyons and Paris, was a believer in the contagious nature of the disease, but it was not till the nineteenth century had almost arrived that general acceptance was given to the view that glanders might be contagious ; and even then another fifty years was to pass during which authorities held that, although contagion played a part, yet other causes might give origin to the disease. The Lyons School and its graduates supported a contagious origin, the Paris School took the oppo- site view, and so prevention was neglected. In 1773, Vitet expressed the opinion that glanders consisted in a dis- charge from the nose of " a virulent and contagious humour," and he stated that " the chest and tlie head were the seat of the disease." In the same year, Volpi of Milan thought he noticed' an analogy between syphilis and glanders, and suspected that glanders and farcy, from their frequent association, might be the same disease. He also asserted that " glanders is caused by contagion alone." In 1797, Eric Viborg, a Danish veterinarian, published a work on glanders in which he showed that there was a specific virus in the purulent discharges of horses suffering from glanders and farcy ; that- farcy and glanders were one disease ; that the virus could be destroyed by heat and desiccation ; and that infection could be carried by harness or utensilsj and more particularly by forage left in mangers from which diseased horses had fed. He also recognised a latent form of disease which might be infective, and warned against the danger from horses which had been apparently cured of farcy. It is sad to think of the losses which have since occurred,, and which might largely have been prevented had the work of this excellent observer been accepted. Viborg, in 1797, knew practically all that was known about glanders up to the time of the discovery of the Baoillus mallei. In the nineteenth century knowledge of glanders progressed slowly at first. Professor Coleman, who had succeeded St. Bel at the London Veterinary School, devoted much attention to glanders. He proved experimentally that farcy might be produced by inoculation of matter from acute glanders, and glanders by the inoculation of matter from farcy. He showed that the virus might exist in the blood by inducing GLANDERS 61 glanders in a donkey through transfusion of blood from a glandered horse, and yet he held that the disease might originate without contagion. Professor Sewell, in 1827, taught that the lungs were the original seat of the disease and the affection of the nose secondary.. He behaved that the miUary nodules in the lung constitute the original disease. In 1840 a series of experiments were made by Renault and Bouley at AKort, which estabUshed beyond a doubt that glanders was contagious ; and since then very few men have ventured to deny that glanders may be transmitted by contagion. But many have, behaved that it, might arise from other causes, such as the introduction into a horse's system of purulent fluids, or even by changes in the blood resulting from defective hygienic conditions. In 1843-50 WilHam Percival published his well-known work on "Hippo- pathology— a Systematic Treatise on the Disorders and Lameness of the Horse." In vol. iii. (revised edition, 1860) is an article on Glanders, extending to 200 pages, and embracing a most careful and extensive review of the work done on the disease by every writer from SoUeysel downwards. Percival himself says : " No doubt has ever been entertained by me of the spontaneous origin of glanders and farcy — of their origia apart from the influence of contagion." Further on we find : " Of the nature of the (so-called) virus of glanders we know no more than we do concerning the supposed viruses or poisons of syphilis, rabies, or variola. We have the same ground for arguing the existence of virus as there is for doing so in the diseases just named, and no more. . . . We do not imagine that simply an unhealthy or iU-conditioned state of the body can give rise to glanders or farcy. We believe that the specific virus must, in some form or another, somewhere or other exist." For many years after Percival wrote, the views expressed by him were generally accepted, and few practitioners disbeheved in the occa- sional spontaneous origin of glanders. " Miasmas " or " mephitic vapours " arising from bad ventilation and overcrowding, tempered by cUmatic changes of an indefinite kind, were the assumed cause of out- breaks which could not be traced directly to contagion. Thus practical measures of prevention were neglected, or limited to the isolation of the most marked cases. In 1882 the causal organism. Bacillus maUei, was isolated and culti- vated in France by Bouchard, Capitan, and Charrin, and, about the same time, independently by Loeffler and Schiitz in Germany. In 1891 the Russian veterinary surgeons, Helman and Kalning, obtained from sterilised cultures of the bacillus a product called " mallein," which possesses the remarkable property of causing a specific reaction 62 SYSTEM OF VETEBINARY MEDICINE when injected into glandered' horses, but which has no effect in horses free from glanders. Schiitz, Roux, Nocard, McFadyean, Kitt, and Bahes, have since added considerably to our knowledge, and Govem- ments in various parts of the world have issued regulations for the control of glanders based upon the results of veterinary observation and scientific research. During the years 1891-92 no less than seven Buropea,n scientists working at glanders lost their lives through accidental infection. DISTRIBUTION AND PREVALENCE. Glanders has been distributed by trade or war to every country in the world. In Europe it has been known for centuries. In India and China probably as long. All the great wars have increased its prevalence, and often carried it into districts where previously it was unknown. In the Crimea glanders prevailed widely. In the Italo-Austrian, in the Franco-Prussian, and in the Civil War of the United States, glanders pre- vailed not only during the wars, but even more actively after peace was made, by the movement and dispersal of superfluous horses. Our minor wars in Egypt, Abyssinia, and Afghanistan were all attended by glanders to an extent which interfered with efficiency. The United States are said to have introduced glanders into Mexico and Cuba with their army horses. The South African War, where 240,000 horses perished, was not only accompanied by the prevalence of glanders, but left the whole country infected. The disease was carried to South Africa from home, from America and Australia, and possibly from Europe, by the remounts. By trade we have received glanders from the United States, Canada, and Europe, and we have returned it. The trade in old horses to Belgium has introduced glanders to that country frequently. Probably no civil- ised country on the face of the earth is now free from the disease. In Great Britain few counties remain free for any length of time, but the disease chiefly prevails in the large towns — ^in London and Glasgow especially. ETIOLOGY. Glanders arises from the development of a micro-organism, the Bacillus mallei, in the system of an animal. In 1882, Loeffler and Schiitz, in Germany, discovered the bacillus ; so, too, about the same time, did Bouchard, Capitan, and Charrin, working independently in France. They isolated it, cultivated it", and produced glanders in animals by inoculation of the culture. The bacilli are found in the discharges from glanders lesions, in un- GLANDEES 63 opened farcy buds, and in the nodules formed in internal organs. In the lungs the most recent nodules afford the larger number of active bacilli. BACTERIOLOGY. The microbes are rod-shaped organisms, about 3 to 5 microns in length by 1 in breadth. The extremities are rounded. The bacilU are non-motile, can be stained by suitable reagents, but are not very retentive of the stain. They can be cultivated in suitable media in the presence of air and at temperatures varying from 75° to 103° P. They cease to grow at 112° and below 60° F. At 130° F. they are killed. Upon agar the colonies form a whitish layer. Upon potato there forms a yellowish, honey-like layer which becomes gradually darker, varying from hght brown to chocolate. The formation of spores has sot been demonstrated. These cultures, when inoculated into susceptible animals, are more virulent than any products of the natural glanders lesions. Accidentally men have been infected by needles and syringes which had been used for experimental inoculation of animals, and in every case death from acute glanders followed. " Horses, asses, mules, cats, goats, field-mice, and guinea-pigs, have all been infected. Rabbits, sheep, and dogs are slightly susceptible. Cattle, swine, and white mice have an immunity " (Crook- shank). By passidg the bacilh through different animals their virulence may be decreased or increased, and it is said that the microbe becomes most virulent in man. Subcultures rapidly lose their virulence. The bacillus can with difficulty be isolated from the blood. It probably does not retain its vitality long in the blood-stream ; but that it exists there in acute cases is shown by the successful production of glanders by transfusion of blood from a diseased into a healthy animal. The baciUi of glanders are killed by exposure to bright sunlight, by desiccation, and by a temperature of over 130° F. They remain active for about eighteen days in clean water, and cannot retain their vitality out of an animal body or a bacteriological laboratory for more than three months — seldom over six weeks. Most disinfectants destroy the bacillus rapidly. A 5 per cent, solution of carboUc acid or a solution of corrosive sublimate, 1 to 1,000, are quite reliable. Lysol, permanganate of potash, chinosol, and many others, may also be used. INFLUENCES AFFECTING INFECTION. As some species of animals are immune to glanders, and as some have a partial immunity, so some horses, if not altogether immune, show 64 SYSTEM OF VETERINARY MEDICINE a strong resistance. When it was permissible to treat cases of glanders and farcy, there were instances of apparent recovery after the exhibition of clinical symptoms. Many horses made partial recoveries, and some recovered and worked for years without ever showing any further sign of disease. Horses have frequently been known to work with, and to stand in the stables alongside, visibly glandered horses, and yet never show a sign of infection. The most probable explanation is that they were infected, but did not develop the disease. I am inclined to doubt whether any horse was ever sufficiently resistive to be immune to a full dose of glanders virus such as exists in' a pure culture, but my experience warrants me in sajdng that numbers of horses naturally infected have lived and worked for years without giving evidence of their infection. Age has a decided influence on the susceptibiHty. Old horses with- stand the disease to a' marked extent. Young horses are easily infected, and the period is short before they give signs of their condition. Over- worked or badly-fed horses are easily infected, and have no resistance to the rapid development of the bacilli. The most resistant horse is the animal in sound, hard condition. Other influences which affect the development of glanders are certain drugs, debilitating diseases, chills, and injuries. So well known was the influence of excessive doses of physio that in suspected cases where no clinical symptoms were visible it used to be a common practice to ad- minister a full dose of aloes. The superpurgation which followed was often accompanied by the signs of glanders. Following upon influenza or acute chest affections, glanders commonly develops if the patient be suffering from the latent disease. , Wounds and injuries are frequently the cause of latent glanders awakening into active disease. In a stud where latent glanders existed it was no im- common event to have farcy in a leg following upon injury to the foot by a nail in shoeing. That the injured part should be the first to show symptoms of the disease is, I beHeve, explainable on the supposition that in chronic cases of glanders every now and then there is an escape from the lungs of stray bacilli, which get into the circulation, but soon perish if no suitable place for lodgment is found. A suitable place is found in injured tissues, and then the bacillus is detained and actively develops, giving rise to definite lesions. That acute lung diseases may hasten the development of glanders when active nodules are in the lungs I think is certain, but it is also true that pulmonary glanders which has existed for months without any indication of its presence may give rise to pleurisy and pneumonia. At a post- mortem examination, when acute pleurisy and old-standing glanders lesions are found, I know no way of distinguishing by naked-eye examina- tion whether the pleurisy is specific or otherwise. SUSCEPTIBILITY OF DIFFERENT ANIMALS. Nearly all warm-blooded animals are susceptible to glanders infection except the ox, pig, and white mouse. The ass is particularly susceptible to infection, and generally succumbs rapidly to an acute attack of the disease. Chronic cases of glanders in the donkey are almost unknown. The mule is easily infected, and the resulting disease is usually rapid. It takes a sort of intermediate position between the horse and ass. The larger carnivora have suffered from glanders by the ingestion of uncooked flesh of -glandered horses. The disease in these animals was probably produced by flesh from subacute cases of equine glanders, as the blood in chronic cases does not seem dangerous. Dogs are very resistant, no case having been reported of natural infection. By inoculation a local sore is produced, which heals spontaneously without producing a general infection. Man suffers both from the chronic and acute form of glanders, and may be infected eitheir by ingestion or inoculation. PERIOD OF INCUBATION. This expression is generally understood to mean the time which elapses between the date of infection and the appearance of the disease. When horses are infected by direct inoculation of active virus from a glandered animal, they give evidence of infection in from th-ee to five days. The local sore becomes angry and ulcerous, whilst the lymphatic vessels are distended and the nearest lymphatic glands enlarged. When horses are naturally infected, or when experimentally given glanders virus in their food or water, no evident symptoms of disease are noticed for some weeks, or it may be months. Keoent experiments, done with more care than was taken a generation back, suggest that infection takes place and produces some constitutional disturbance, , though slight and temporary, long before the visible appearance of external symptoms. The daily use of the clinical thermometer after infection frequently indicates a rise of temperature in a few days. A post-mortem examination discloses nodules in the lungs. In natural imjedion the usual period of incubation— that is, the time between the reception of the virus and the appearance of clinical symp- toms— is /roiw one to three months, but in many cases much longer. The fact is that, although after infection no chnical symptoms may arise for an indefinite time, glanders lesions are being formed in the lung, VOL. I. ^ 66 SYSTEM OF VETERINAEY MEDICINE and this latent pulmonary disease may, according to the state of the horse and the influences affecting him, develop slowly or rapidly, and in some cases cease to develop. METHODS OP INFECTION. As the only cause of glanders is the Bacillus mallei, no case can arise except by the passage of the bacillus from a diseased to a healthy animal. Of course, the passage need not be direct. The bacillus may leave its habitat, and remain on some place or material from which it may reach the system of the animal. So long as it retains its vitality out of the body, it may be infective. Thus it is that the exact way in which the disease is spread is often involved in doubt. A glandered horse may leave infective material on food or in water and pass on. The food or water may not be consumed by a healthy horse for some time after, and the connection between the infecting and infected horse is never known, but is none the less real. Horses suffer from glanders lesions which may be open or closed. A farcy bud on the sldn allows no escape of bacilli until it is opened. A glanders nodule in the lung is for a time closed, and only when some change occurs in it do bacilli escape — it may be into lymph vessels or it may be into bronchi. In the one case they may pass from the bronchi up the respiratory passages and set up ulcerations on the mucous mem- brane ; in the other they escape into the lymph-stream, and if not soon detained to form fresh centres of infection in the lung, they reach the circulation, and may give rise to lesions in any part of the body. The open lesions of glanders are those in the air- passages — trachea, larynx^ and nose — and on the skin, " buds '* or tumours which have broken and ulcerated. The discharges from these contain the virus, which spreads infection, either directly or indirectly, to healthy horses. There are three ways by which the virus may enter the body : : (1) Through the skin or mucous membrane ; (2) through the air-passages by inhalation ; and (3) by ingestion through the digestive tract. Direct experiment has demonstrated that susceptible animals may be infected with certainty through the skin or mucous membrane, if these are injured. Inoculation introduces the material through the skin. An abraded surface permits infection to pass through, but it is very doubtful if a sound membrane or skin does allow the infection of glanders to pass. Successful infection by rubbing in virulent matter has been attained, but the rubbing may have destroyed the structure of the protecting surface. Abrasions and wounds have frequently afforded access to the poison of glanders. Splinters of wood from an old manger that has been used by GLANDERS 67 a glandered horse might be infected, and then penetrate the skin of the lips of another horse. Sores might be inoculated by virus iaccidentally transferred on saddles and bridles. A glandered horse, by hcking or biting, might infect a healthy horse. It has often happened that disease has been transmitted by cloths or spongeis used on an unrecognised case of glanders, and then employed to clean or foment wounds on a healthy horse. Direct experiment has also demonstrated the certainty with which glanders can be conveyed through food and water recently contaminated by virus from a diseased animal. Viborg, in 1793, recognised this fact by cHnical observation. Simonds gave water containing glanders matter to healthy horses, and transmitted the disease. Renault and Bouley, in 1840, obtained the same results. All these early experimenters laboured under the possible fallacy of their experimental subjects being already infected before being made to swallow the virulent material. No such error could vitiate the experiments of Schiitz, Nocard, and McFadyean, who all tested their subjects with mallein before proceeding. These experimenters used pure cultures, and passed them into the stomach with precautions against any accidental inoculation of the mouth, pharynx, or oesophagus. They successfully infected their subjects, and could always find glanders nodules in the lungs, though seldom any lesions in other organs. From my own clinical observations, I long ago arrived at the con- Adction that not only is infection possible by ingestion, but that this mode of introducing the poison is by far the most common in practice. In a cab stable where two horses work a cab, but stand in different stables — a night stable and a day stable— the disease in one is usually followed by infection of the other, the most direct medium being the nosebag. In ordinary stables, a detected case of glanders is usually followed by the appearance of disease in the horses standing on either side of the diseased one. The transmission of glanders by a common water-trough, or by pails, in stables where glandered horses are kept and worked has been noticed and recorded frequently. It is beyond doubt that glanders bacilli may pass through the stomach and reach the lungs, leaving no trace of their line of progression, but giving rise to unmistakable evidence of their arrival. The baciUi of glanders escape from the nose of an infected horse, with pus or mucus, in a wet condition, and are not long floating in the air. They fall upon mangers, walls, forage, water, and so are ready for ingestion. If they become dry, they must be detached from the surface on which they are dried before being capable of floating free. Desiccation is fatal to the 68 SYSTEM OF VBTERINABY MEDICINE bacillus. Even supposing a few chance bacilli retain their, vitality, and, floating in the air, are drawn in with the breath into a horse's nose, how many are likely to escape detention by the moist passages of the nose, pharynx, larynx, and trachea, and to gain access to the lung ? The analogy of the miner and the coal-dust is not applicable. The air which caused miner's lung was absolutely full of suspended particles, and improved ventilation in mines has rendered miner's lung a rare curiosity. How many glanders bacilli, dry but vital, could be found in a cubic yard of air in the most frightfully infected stable is a metaphysical puzzle incapable of solution. It may be added that experimental attempts to produce glanders through aerial infection have never been successful. METHODS OF SPREAD. I have just attempted to show how the infective virus of glanders leaves a diseased horse, and how it enters the system of a healthy one. The fact that the virus remains active outside the body of an animal for at least some days renders it necessary to keep observation, not only upon the diseased horse, but upon the various ways in which infection may be carried. Most important of all is it to know that a horse, apparently quite healthy, may be a source of infection. The latent form of glanders is probably not infective until some open lesion occurs, but this may happen without warning. Ulcerative lesions may arise in the trachea, rendering the horse infective, and afford no clinical evidence until they have largely developed — a dangerous condition extending over some days, during which time the horse is excessively dangerous to all around him, but is unsuspected. Then, again, visible disease may not be recognised. Although a very evident nasal discharge exists, it may be mistaken for catarrh, and so mangers and pails are infected, and other horses are allowed to use them. Every nasal discharge should be looked upon with suspicion until its nature is satisfactorily diagnosed. Sponges, leathers, combs and brushes, may carry the disease from one horse to another if they are used upon an infected animal. Of course, precautions would be taken if it were known that a diseased horse were on the premises, but latent disease is not recognisable, and it so suddenly develops in many cases that contagion is carried before it is known to be present. There are in London many infected studs. Bankruptcy and death ; cause the sale of these, and the owners, without selling a single developed case of disease, often spread infection to many centres by distributing horses suffering from latent glanders. GLANDEES 69 In large studs having many different stables, glanders is spread to a great extent by the constant changes of horses from stable to stable to suit the exigencies of business. When once infection is introduced to such a stud, the changes of horses spread the disease to every stable unless very careful measures are taken to prevent it. Newly-purchased horses are a frequent means by which glanders ia brought into a stable. Purchasers who confine themselves to young horses from the country seldom introduce glanders, but men who buy aged town horses are never long before they have the misfortune to get an infected horse. A horse put up at livery may eat out of a manger which has been used by a glandered horse. A healthy horse may stand next to a diseased one in a shoeing-forge, or in a railway horse-box. Drivers of horses may change nosebags, and one of the horses be glandered. Horses may be turned out to grass in the autiman, and there meet with an infected animal. I once saw five visibly glandered horses in a field with thirty others. Probably these animals belonged to ten different owners, and ten different stables would ultimately become infected. In no small stud does glanders remain long, because it soon kills all the horses. The disseminating centres are the large studs, and the spread from them is by the cast horses with latent disease which are purchased by the poorer owners, and not suspected till too late. Out-of-the-way places — villages and farms — have become mysteri- ously infected, and some such cases have been directly traced to travelling shows, circuses, and gipsies. Of course, all sales, fairs, and markets may disseminate infected horses. The way to prevent such an occurrence is not to close the yards and markets, but to look after the infected animals, and detect the latent cases. One method of spread I must specially refer to — the public water- trough. It is quite possible that some cases of glanders have arisen as the direct effect of drinking at a public trough, but they are very few and far between. I have an intimate knowledge of the stables of three contractors who have had, during the last twenty years, four outbreaks of glanders in their studs. Each outbreak was clearly and directly trace- able to the purchase of a horse from an infected stud, and was stamped out at once without spreading. Save these outbreaks, no glanders has troubled them, and yet their horses travel all over London, and drink at any water-trough they can reach. I feel convinced that infection from water-troughs is very rare, because in 90 per cent, of all outbreaks which I have personally investigated other methods of infection are traceable. Even i£ 5 per cent, of all outbreaks in London were traceable 70 SYSTEM OP VETERINAEY MEDICINE to the water-troughs, the gravity of the rfek would be no argumeat in favour of closing the troughs, especially in summer. The harm resulting to horses from being denied water all day would cause a mortality greater than is caused by all the glanders in the MetropoUs. The fact that an occasional case of glanders may be due to public water-troughs is an argument for the extermination of the disease, but not for closing the troughs. MORBID Alf ATOMY. There is only one post-mortem lesion that may be expected in every case of glanders — viz., nodules in the lungs. - On two or three occasions I have failed to find pulmonary nodules in horses which showed during life distinct symptoms of farcy, and I believe these few cases were due to primary infection of the skin, which directly produced cutaneous lesions, and, with sufficient time, would have affected the lungs. The large majority of cases of farcy do not arise in this way. They are secondary signs of a long-established latent infection. This is demon- strated by the old lung lesions found on post-mortem examination. Lung Lesions. — 'No matter in what way the causal organism enters the body, it will find its way to the lungs and produce nodules if the horse survives for a week or two after infection. The lung nodules persist, whilst the lesions caused at the point of entry may entirely disappear. The pulmonary nodule is the most important of glanders lesions ; it is also the most durable. Ulcers on the skin may heal and disappear; ulcers on the mucous membrane of the respiratory passages may "heal, and leave only small cicatrices ; but the lung nodule remains. Every- where on the outside of the body the tendency of a glanders lesion is to suppurate and ulcerate. In the lungs the nodule containing active , bacilli alters but slowly, and the changes taking place in it present little tendency to invade neighbouring tissues or to set up a violent necrotic action. Since horses have been slaughtered solely on the reactions to mallein, lung lesions have been examined in an earher stage, and more or less free from the complications which accompany the generalisation of the disease. Even under these conditions, variations in the size, form, and quality of the nodules are noticeable, due principally to the age of the lesions, but also to the resistance offered by the pulmonary tissue of the individual horse. I need hardly warn professional observers of the difference in all lungs brought about by the method of death, and by the time which elapses before a post-mortem is made. A horse that dies of . glanders', GLANDERS 71 and upon which a post-mortem is held some hours after, shows a deeper colour of all the organs than one which is killed, and probably bled, just before the examination. The side upon which an animal lies after death always shows a darker colour than that which is uppermost. There is a great variation in the appearance of lungs taken from glandered horses. Many pulmonary changes are found which have resulted from inflaminatory attacks having no connection with glanders, which occurred, perhaps, months previously, and which have subsided so far as to show no symptoms of the disease during Hfe. These attacks leave portions of the lungs altered in colour and density. Parasitic invasions also leave their mark, sometimes in the form of large cysts, and sometimes as small, hard, calcareous particles. The small calcareous bodies which feel like shot under the pleura, when of parasitic origin, are generally more uniform and more widely spread throughout both lungs than the glanders nodules. They are all about the same age and density. They are more easily enucleated from their capsule, and the enveloping border is more definitely marked off from the surrounding tissue than in the case of the typical glanders nodule. Another cause of pathological variety is the specific pneumonia or pleurisy accompanying generalised glanders ; also the pulmonary inflammations which may accidentally or coincidently arise in horses already suffering from latent glanders, and which superimpose their lesions upon those of the specific disease. In a case of gangrenous pneumonia, latent glanders in the lungs is generalised with starthng rapidity, and the complication may be over- looked unless care is exercised. The Typical Glanders Nodule is a firm, round body, varying in size from a pin's-head to a horse-bean. It may sometimes be seen as a little eminence under the pleura, but is best found by passing the fingers with gentle pressure over the wet surface of the lung. If the lungs have been removed for some hours from the carcass, and their surface allowed to become dry, nodules are not easily felt ; they should be examined immediately after removal, or should be wetted before an attempt is made to detect nodules by touch. Nodules frequently exist and afford no evidence to the eye, whilst readily distinguished by touch. The more recent nodules may often be recognised as dark circular spots visible through the pleura. When felt with the finger, they yield ihe impression of firm round objects embedded in the lung. Dark spots upon the pleura are not uncommon in horses quite free from glanders, but they are superficial, not nodular. The term " miliary glanders " is sometimes used to describe the small nodules found in the lungs. It suggests at once a comparison with the 72 SYSTEM OF VETERINARY MEDICINE miliary lesion formed in tuberculosis, in which thousands of small tubercles are distributed evenly all through the lungs. Such a condition is seldom found in glariders, although nodules may exist throughout one or both lungs. The glanders nodules are found irregularly here and there, chiefly on the upper surface of the lungs — as a rule, more in one lung than the other. They often differ in age — some so old as to have become gritty, some caseous, 'and some merely dark hsemorrhagic centres. Continental observers have described as the earliest stage of lung lesion due to the lodgment of the Bacillus mallei a yellow semi-transparent speck about the size of a pin's-head. I confess I have not yet recognised this condition. The earHest change I am conversant with is a dark hsemorrhagic sphere, not very clearly defined from the surrounding lung tissue at its circumference,' especially when exposed by a deep cut into the lungs. How long this condition remains I do not know, but from a few cases in which the period of infection was known I estimate such nodules to have been in existence for about a month or six weeks. The next stage is for this dark spot, when incised, to present a centre of a yellowish-grey colour, which in course of time increases in size and becomes lighter in colour. As the light- coloured centre increases in size, the surrounding dark zone contracts and becomes more distinctly defined from the surrounding lung. This change goes on until the whole nodule consists of a caseous grey mass, varying in size from a pin's-head to a pea- The caseous nodules, if the horse lives, undergo a further development ; they become gritty from calcareous alteration, and in some of the very oldest lesions we have a hard, solid, round body, not unUke a coated pill, which may be enucleated from its surrounding capsule. The fact of nodules of varying age existing together in a lung is not due to various dates of infection, but to the more or less constant escape of bacilli from the earlier nodules. These bacilh become lodged, and form fresh nodules, and so we have from one infection an increase of nodules which may continue for years. There are often very few nodules in a lung, but no one should say there are none until he has not only felt every part of the organ through the uncut pleura, but shced the lungs and examined each section with fingers and eyes. When making deep incisions into a lung in search of glanders lesions, it should be remembered that the round nodule may slip aside from the knife, and then does not disclose the characteristic Hght-coloilred centre. It appears as a dark round prominence on the cut surface, and should be carefully divided so as to display its centre. Every stage of the nodule may be found deep in the lung tissue, as GLANDERS 73 well as just under the pleura ; but they are less easily detected, owing to the colour of the surrounding tissues and to the haemorrhage following the incision. In some of the older cases very few dark-coloured nodules are found, but the incised surface shows numbers of small grey caseous masses, about the size of a small mustard-seed, without any hsemorrhagic zone surrounding them. So far I have attempted to describe a typical glanders lesion, but there are others not so well defined. There is a nodule or small tumour, varying in size from a hazel-nut to a walnut, which is easily seen as a prominent object under the pleura, this membrane being opaque and thickened over it. When cut into, the nodule is of irregular form and partly caseous. The section is not like that of the typical nodule which has a well-defined centre. It appears to have penetrated into the lung substance — a sort of interstitial infiltration — so that portions of lung tissue intersect the nodule, especially at its circumference. Sometimes these lung nodules show, when cut into, three or four separate caseous specks, or each may be a distinct abscess. Pneumonia is always present in acute cases, and the whole lung is dark and congested. In some places softening has occurred, and small abscesses are found ; but cavities such as occur in tuberculosis are rare in glanders. Large dark-coloured masses, the size of an orange, are some- times seen, which, when cut into, show one or more small abscesses. Similar lesions are seen in cases of pneumonia not accompanied by glanders, and therefore they cannot be accepted by themselves as evidence of the specific disease. When glanders nodules happen to be situated in a portion of inflamed lung, they very rapidly develop, forming small abscesses, containing pus of a firmer and more caseous quaUty than that due to other pulmonary inflammations. Pleurisy is not uncommon, and may be specific or coincidental with latent glanders. A firm layer of tough adherent lymph covers the pleura, and effectually prevents the detection of nodules by the hand. Unless a lung is well filled with nodules, the changes resulting from acute pleurisy may render it very difficult to decide whether pulmonary glanders is present or not. Fibroid Changes in the lungs as specific glanders lesions are not often seen. Occasionally a swelling the size of a small apple is met with, which, on being cut into, is found firm, hard, and light-coloured. Prob- ably such morbid changes have no relation to the glanders lesions also present. The extensive fibroid change which is described as due to old- standing tuberculosis is very rare in glanders. Only once have I seen a 74 SYSTEM OF VETERINARY MEDICINE lung the borders and apex of which were so firm and hard that it could hardly be cut with a knife. That case, I know, was infected for nine years, although it showed no clinical sign of disease, except for the first three months of that time. The Spleen. — ^Next in frequency to the lungs, nodules are found in the spleen. They may be detected by the fingers as small, firm bodies under the capsule. They are generally rendered very noticeable by a red or a reddish stain of the capsule covering them. When cut into, they resemble the pulmonary nodule, but are seldom seen in the hsemorrhagic stage, if that is ever the primary state of a splenic nodule. The grey mass which they usually present when incised is firmer than the similar lesion of the lung. The Liver is not often the seat of glanders nodules, but they are occa- sionally found in this organ. They present the form of a whity-grey spot on the capsule. The Kidney is very rarely the site of glanders lesions, and, when they are found, their nature can only be determined by biological experiment. The Intestines are said to disclose glanders ulceration to careful' observation. I have never seen such lesions. They would be most likely to exist very shortly after ingestion of active bacilli, or in a very acute case of generalised glanders in which the virus from ulcerated respiratory passages passed into the pharynx and then through the stomach. Lesions of the Respiratory Passages. — The lesions found on the mucous membrane lining the respiratory passages are vesicles, nodules, vicers, infiltration, and cicatrices. These, except, perhaps, the infiltrations, are always secondary lesions, caused by the escape of bacilli from nodules in the lungs. I have never seen ulceration of the nasal or tracheal mucous membrane without finding nodules in the lungs of an age much greater than that of the ulcerations. The Vesicle is a small circular bhster, almost transparent. In a few hours the upper part of the raised membrane gives way, disclosing a red sore, which rapidly proceeds to ulcerate. These vesicles may be soUtary, but more often are found in clusters. As each breaks down and forms a sore they coalesce, and thus we have the rapid appearance of extensive ulcerated patches so noticeable in the more acute cases of glanders. Nodules may occur on the septum, larynx, and trachea, but are not common in these situations in the horse. They are small, white, firm bodies about the size of a small pea, or less. They are more persistent than the vesicle, but ultimately break down, forming a sore, which rapidly ulcerates. GLANDERS 75 Ulceration. — ^This is the most marked lesion of glanders. It is found in all clinically developed cases either on the skin or on the respiratory mucous membrane. As a rule, the ulcers are distinct and separate, but frequently we find them coalescing to form a large continuous ulcerated surface, and I have seen cases in which the whole of the nasal mucous membrane was affected, as well as most of that covering the larynx and trachea. The turbinated bones and the large sinuses of the head are often affected, in addition to the nasal cavity. Even the guttural pouches and Eustachian tubes have been found ulcerated. Tracheal vlceration presents two very different forms, one — the more common— in which large soUtary ulcers are found quite apart from each other. They are not below the surface of the surrounding tissue, but , prominent and raised, dark in colour, and bathed in pus. The other form resembles a series of red streaks running always vertically to the direction of the trachea. They are not solitary, but are found in great numbers, often extending over the whole length of the mucous membrane. They may be well described as narrow sUts through which protrudes a bright red granulation. Laryngeal ulceration usually takes the form of isolated ulcers, varjdng in size up to that of a sixpence. They are found on the epiglottis, on the vocal cords, and on the border of the arytenoids, as well as on other parts of the laryngeal membrane. In a few cases the whole larynx presents one continuous ulcerated surface. Nasal ulceration is usually found in long patches on the septum nasi, and a similar form is seen on the membrane covering the turbinated bones. In some cases it is located high up on the septum, in others we find only one, or perhaps two, small ulcers at the lower end of the cartilage, which are visible during life. In some chronic cases, when nasal ulceration has been continued for a long time, we Inay have perforation right through the septum, and this conditioii is found more often at the lower extremity of the septum than at the upper. The usual colour of the ulcerating surface on the membrane hning the respiratory passages is an angry red, covered by a blood-stained muco- purulent secretion. In a few cases we find a pale yellowish-grey surface covered with a viscid translucent mucus. This condition is the healing stage of the ulcerative process. Cicatrices are found in the trachea, larynx, and nose. In the two first positions they are generally small, but on the nasal, membrane covering the septum they may be extensive. Their usual size is about that of a shilling or less. They are irregularly stellate in form, smooth, 76 SYSTEM OF VETERINARY MEDICINE and white. In conjunction with a recent cicatrix, it is not uncommon to find neighbouring lesions in a healing stage ; instead of the angry coloured ulcerations, we see straw-coloured masses of granulation tissue. Nowadays, when cases of glanders are closely looked after in London, and slaughtered as soon as detected, these cicatrices are becoming very rare. A stellate cicatrix on the septum of a horse so seldom results from anything but a healed glanders ulcer that its presence should suggest an immediate test with mallein. Infiltration. — In glanders the nasal septum is often the seat of thick- ening and discoloration, with no ulceration. Sometimes the whole sub- stance of the membrane is a bluey-black colour, raised and thickened by effusion beneath it. When the discoloration is only partial, the rest of the membrane is prominently marked by distended small veins. I have found portions of the membrane covering the septum almost black, and raised quite J inch by effusion under it. On cutting through the mem- brane a dark sanguineous mass was found, firmer than clotted blood, almost the consistency of a soft tumour. I ought to add that in some cases of farcy I have seen this infiltration accompanied by very few pul- monary nodules, and I am not sure that, like the ulcerations, it is always due to the escape of bacilli from the lungs. So frequently in cases of farcy do I find the membrane covering the septum infiltrated, but not ulcerated, that I have formed the opinion that the nasal membranes are specially selected parts for the attacks of glanders; just as the feet and buccal membranes are for foot-and-mouth disease in the ox. The fre- quency of nasal ulceration is easily accounted for by the passage upwards from the lungs of glanders bacilli. But nasal infiltration is found accom- panying cutaneous glanders, even in cases where no pulmonary nodules can be detected. Glandular Lesions.— Among the symptoms of glanders I shall mention enlarged glands. Post mortem they can be more thoroughly studied than during hfe, because available both before and after section. The submaxillary gland is often enlarged, and although it seldom forms an abscess such as occurs in strangles, we may, on section, find small col- lections of caseous pus. The more common changes in the gland are softening and distension of the lobules by effusion within them, a yel- lowish exudate in the connective tissue around them, and one or more grey spots in the lobule when incised. Lymphatic lobules vary in colour in healthy horses. They are yellowish-white, reddish, or sometimes black ; but whatever the colour, it is uniform throughout. Whity-grey centres in the lobules are the lesions of glanders. The bronchial and •thoracic lymphatic glands are often the seat of lesions in glanders, but GLANDERS 77 not so often as when the lungs are affected by tuberculosis. The mesen- teric glands are seldom the seat of any specific lesion in cases of natural infection. Glanders, experimentally produced by ingestion of pure cul- tures, has caused mesenteric lesions, but it must be remembered that the culture used contained probably a hundred times as many active bacilli as would be found in a similar quantity of the most virulent natural infective material. Muscular Lesions are found in man in the form of large intramuscular abscesses. I have never seen such changes in the horse, nor do I recog- nise any other muscular lesion in this animal. Joint Lesions. — Not often does glanders in horses cause any change in joints which can be detected after death. I have seen hocks and knees during life show synovial distension without any signs of acute pain. In man, joints frequently are enlarged and painful in acute glanders, and are sometimes the seat of purulent synovitis. Such a con- dition in the horse, I beheve, is unknown. Cutaneous Lesions are tumours, abscesses, ulcers, and inflamed lymphatic vessels. The larger tumours I shall describe in the section on sjTnptoms. The smaller, known as farcy buds, occur singly or in chains. Appearing first as small, round, hard tumours, they soon soften, the top gives way, allowing the escape of a dirty blood-stained pus or of an oily fluid, and the base remains, showing an angry red surface, with little tendency to heal. The IjTnphatic vessels around this " bud " become inflamed and swollen, along their course other buds form, and so we have the familiar chain of buds connected by enlarged lymph vessels — ^the so-called " cords." When the cutaneous form of glanders is permitted to exist, a very large area may soon be covered with " buds," ulcers, and " cords." In some chronic cases a bud or two make their appearance, enlarge slowly, and then as slowly decrease and disappear. When the skin is removed from a part showing cutaneous lesions, a condition is often revealed quite disproportionate to the mild changes seen on the surface during Ufe. The lymphatic vessels have become purulent sinuses ; subcutaneous abscesses, sometimes the size of a man's hand, are found, and a large area may be infiltrated with straw-coloured effusion. All these different lesions may be found in one case, but not often. Sometimes we find only one or two, sometimes a number ; but the associa- tion of lesions apparently follows no rule, and the results of a post-mortem examination can never be anticipated with any certainty. The development of glanders lesions is most irregular in cases of natural infection. Some horses that we know have been long infected show very few lesions on a post-mortem examination ; others with a 78 SYSTEM OF VETERINARY MEDICINE short period of infection are found after death to present extensive morbid changes. Doubtless one cause of this variation is the dose of bacilli received at the time of infection. One horse may be infected by one dose of virus contained in one feed or one pail of contaminated water ; another may for many days be stabled alongside an infected animal, and thus ingest a number of small but repeated doses. Then there is the state of the horse to remember — his individual resisting power or his susceptibility. One may be infected and live a year or more without a clinical sign of infection showing ; another dies of generalised lesions in a few weeks. It is, therefore, almost impossible to form an exact opinion, even after a post-mortem examination, on the question of the duration of the disease. In only a few cases where an autopsy is possible do we know the exact date of infection ; and unless this is known, it is impossible to arrive at a sound basis for any definite conclusions. Without sufficient data, but with a number of cases in view in which a post-mortem has been obtained, and in which the time of infection has been fixfed to a week or two, I have ventured to form some opinions. When the lung lesions are only hsemorrhagic nodules, they are not more than a m,onth old ; when nodules are caseous, they may be six months ; and when calcareous, probably twelve months old. When nodules of all stages exist, I fix the duration by the state of the oldest. In cases where acute glanders has existed for some days, or in which infected horses have been continuously overworked or underfed, I think it probable that my estimates of duration would be useless, and that the changes in the lungs would be much more rapid up to the caseous stage. A similar difficulty occurs in fixing the age of ulcerating lesions. In some horses extensive changes occur in a day or two ; in others ulceration goes on for a week or two, and then is limited to patches. In the majority of cases it is very rash to express an opinion as to the age of glanders lesions. Very httle assistance is given the chnical observer by the experiments of pathologists, who use pure cultures as infecting media. I suppose that a fluid drachm of a pure culture, or a scraping from a growth on potato, might contain as many active baciUi as ^ pint of any natural infective discharge. The result is that these artificial infections act much more rapidly and with tenfold more violence than any natural infective material. Nocard, Schiitz, and McFadyean have experimentally produced glanders by causing horses to swallow pure cultures of the bacillus. In some of Nocard's cases clinical symptoms were evident. on the eighth GLANDERS 79 day, and mallein gave a reaction on the seventh. Horses killed fifteen days after infection were found by Nocard to have their lungs full of nodules in all stages. Horses killed three months after infection had their lungs literally crammed with nodules — ^fibrous, calcareous, and caseous. Schiitz made post-mortem examinations on the fourteenth, fifteenth, and twenty-fifth days after infection, and found nodules in the lungs. He also found what Nocard did not describe — enlarged mesenteric glands, nodules in the spleen and intestines, enlarged abdominal lymphatic glands, and distended chyle vessels. Nocard found calcareous nodules in a case only three months after infection. These findings are certainly not in accordance with the lesions seen in natural infections. I thiik I may say positively that I have never seen calcareous changes in lesions less than six months old. McFadyean infected four ponies by administering scrapings from potato cultures in such a manner as to avoid any method of infection save that of ingestion. In each case glanders nodules were found in the lungs, but only in one were distinct lesions found in the mesenteric glands. These experiments afEord positive evidence that infection by inges- tion of glanderous material may produce nodules in the lungs in from eight to twenty days, and cause no macroscopic lesion in the abdominal organs, through which the bacilli must have passed. In one case mesen- teric and intestinal lesions were caused, and probably were noticeable owing to the short time which elapsed between infection and the post- mortem examination. Incidentally, another fact was disclosed in these experiments — ^that each case, except the first, reacted to an injection of mallein on the thir- teenth day after infection. SYMPTOMS. Although there are cases in which the symptoms of glanders may well be described as acute, and others in which they may be called chronic, the difference is only one of degree, dependent upon the activity of the bacilli or the resisting power of the horse. If we divided the disease into acute and chronic, we should have to add another division — subacute — which would probably include more of the cases seen in practice than the other two forms added together. I do not, therefore, propose to give separate descriptions of the two conditions. Again, glanders may , appear in the cutaneous form or in the nasal form, but it is superfluous and erroneous to divide a description of symptoms into those of glanders and of farcy. In many cases the symptoms are mixed, but the cutaneous form seldom or never kills without the advent of other lesions. 80 SYSTEM OF VETEEINARY MEDICINE Loss of energy may appear without any apparent cause, and without loss of appetite. It may be temporary, but recurrent. Probably it is only noticed by the driver, who complains that a previously energetic horse has now to be encouraged with the whip. Cough, short, hollow, and provoked by exertion, should suggest inquiry for some definite cause. Grunting, when the horse is turned round or when threatened, is usually a symptom of " roaring," but it is exhibited in most chest afEec- tions of a painful nature. When detected in a horse which is not feverish and not a " roarer," and when accompanied by signs of pain on pressure in the intercostal spaces, it is suspicious. Polyuria — excessive secretion of urine — is another sjonptom seen frequently in advance of the generalisation of glanders. It is also some- times noticed in tuberculosis. When only one horse in a stud shows this symptom, it may be looked upon as suspicious. The Temperature, as indicated by a cHnical thermometer, is very indicative. Whenever a horse with apparently no definite disease shows a fluctuating temperature, rising to 102"5° F., and falling a degree or two, only to rise again, glanders or tuberculosis may be suspected. In some cases the temperature remains pretty constantly at 102° F., with occasional rises to 103° F. Such horses may work, and give little other indication of anything abnormal, but they should be put under close observation and rested. We now test such horses with mallein, but in the days when that agent was unknown a constant use of the clinical thermometer in an infected stud was a useful but tedious method of picking out and isolating horses, which were then carefully watched. Many cases in time showed development of other symptoms, which proved the value of the thermometric index. In clinically visible glanders there is always a rise of temperature, and in acute cases it may reach 107° F., when, of course, constitutional disturbance is also well marked. In chronic cases the temperature varies a great deal, and may not rise over 102° F., but as a rule it is higher. The temperature does not seem to be proportionate either to the extent of glanderous lesions in the lungs or to the amount of ulcerative change in the air-passages, although, of course, when this is excessive, a rise of temperature always exists. I incline to think that the fever in glanders depends upon the escape from open lesions of the products of the causal organism, and that when the bacilli infect the blood-stream the tempera- ture rises ; when the lesions are closed, no escape of bacilli or their products takes place, and the temperature is not affected. Coming to the more definite indications of glanders, we have a long GLANDEES 81 list of separate symptoms, whicli may appear singly or in numbers. No one symptom can be said to be always the pioneer. Sometimes one, sometimes another, ushers in the disease, and therefore the order in which they are described is m.erely a matter of convenience. Constitutional Disturbance, as evidenced by fever, loss of appetite, and some quickening of circulatory and respiratory movements, usually attends the onset of glanders. It may be temporary and be overlooked, and it may not appear till the arrival of other symptoms. This is the stage at which errors are often made, and a diagnosis of common cold or catarrh may distract attention from the real mischief. Such an error is easily made, and when no more definite symptom is visible we cannot blame the practitioner. Any slight constitutional disturbance accom- panied by a nasal discharge should be suspected, unless some definite disease is recognised. When in doubt, the mallein test should be applied. Glandulax Enlai^ements.— The most frequent glandular enlargement is that of the submaxillary lymphatic glands. As a rule, the gland on only one side is affected, but in a few cases both are enlarged. A very slight thickening is the first stage, and in some chronic cases nothing more is noticeable for weeks. The gland may reach the size of half an apple. It is hard, not painful, and very seldom suppurates. Usually it is adherent to the jaw-bone, and accompanied by little or no surrounding oedema. The erdargement of the gland may be the only symptom of glanders, and may remain without complication for a long time; It may be accompanied by an intermittent nasal discharge, which is noticeable during work, but ceases shortly after the horse has returned to his stable. ' The enlarged maxiUary gland is very persistent, but it may entirely subside. In cases where a gland has once been enlarged and resumed its normal aspect, it may become a very prominent hard swelling in the short space of a day, or at most two, but is then always accompanied by some marked development of the disease — by acute generahsation of an old latent infection. ' In Great Britain we have very few cases of glanders in entire horses. In countries where castration is not so general the testicles are often affected, showing swelling and pain on pressure. It should be remem- bered that tuberculosis may cause a similar condition. An undiag- nosable lameness has occasionally been the first symptom noticed in a horse that later has developed glanders, and a post-mortem examination has disclosed specific disease in the inguinal or in the brachial glands. Such cases are rare. When glanders was not so specially cared for as now, in old cases which had been temporarily cured (?) and had again developed, enlargement of the prepectoral glands was occasionally met 82 SYSTEM 01" VETERINARY MEDICINE with. They could be felt in front of the border of the scapula. In cases of farcy with enormous swelling of a hind-leg the inguinal glands are usually affected. Nasal Discharge is a very frequent symptom of glanders. In nearly all but the acute cases the discharge is from one nostril. In acute cases the discharge may be copious and distinctly purulent in appearance, but more often it is muco-purulent, of a dirty grey colour and a viscid nature. It may be streaked with blood. In chronic cases with a one-sided dis- charge the matter is thinner, sticky, and less in quantity. It adheres to the edges of the nasal opening, and is often accompanied by some swelling and hardehing of the skin covering the nares. The nasal discharge in glanders is not proportionate to the amount of ulceration of the nasal membrane, sometimes being shght when deep ulceration exists, and at other times copious, with very few ulcerating lesions. The discharge may be intermittent, and only seen after exercise or exertion. As a rule, no offensive smell accompanies the nasal discharge in glanders. Nasal Nodules and Ulceration. — Very seldom is nasal ulceration seen in any other disease of horses but glanders. It may occur. When it does, the ulcerating surface is raised and prominent, accompanied by very little discharge, and no constitutional symptoms are noticeable. Of course, all such cases should be tested with mallein. Glanderous ulceration may exist high up on the septum, or on the turbinated bones, and cannot be seen during Ufe. When the ulceration is visible, we usually find it lower down on the septum, or within the fold of the mucous membrane which covers the anterior portion of the cartilage forming the alae nasi. White firm nodules are sometimes found on the nasal membrane, but they are not common. They differ in size from that of a pin's-head to a small pea. The most common lesion forming the first stage of ulceration is a small white vesicle, which does not persist, but in about twenty-four hours breaks, leaving a red sore, which forms a rapidly progressing ulcer. This ulcer is round, with dark red circum- ference, a depressed centre, and clean-cut raised border. When near the entrance of the nose, the discharge from the ulcer often forms a soft scab over it, which is easily detached. As a rule, more than one ulcerating spot makes its appearance, and when two or more are near they soon coalesce, forming an angry-looking ulcerating patch. In the worst cases the whole mucous membrane of the nasal passages may be one continuous ulcerating surface, and perforation of the septum has fre- quently been seen. Although the early ulcerations visible on the nasal membrane are rightly described as depressed ulcers with raised borders, those higher up GLANDERS 83 the cavity, or which have existed for some days, are frequently prominent and almost fungous-looking objects. Nasal Infiltration.— In some cases of glanders— frequently in the so-called " farcy " cases— we find no ulceration in the nasal cavity, but a swollen and discoloured membrane of a bluey-black colour. The veins and lymphatics are distended and prominent, but the mucous membrane is unbroken. This blue-black condition of the membrane is also seen in hard- worked old horses, but to a less degree, and therefore is not to be accepted as an indication of infection, without other symptoms. It is, however, sufficiently suggestive to warrant a mallein test. Snuffling and Snoring.— As a result of nasal ulceration and oedema of the mucous membrane of the nose, the passage of air in respiration is obstructed, and we have snuffing and snoring as well-marked symptoms of glanders. These conditions exist sometimes when very little can be detected by an examination of the nose in a living horse. The thickening and ulceration of membrane are too high up in the head to be visible, but their effects are most noticeable. Usually ulceration of the septum can be seen when these sounds are emitted by a glandered animal. Roarii^. — ^When a horse has recently suffered from strangles or influenza, no surprise is felt at the emission of a " roaring " sound ; but when a horse in regular work commences to " roar " suddenly, we are apt to suppose some traumatic cause to be in operation. This may be the very first noticeable symptom of the development of glanders. In every case of sudden roaring, so far as my experience goes, the horse has been the victim of latent glanders, and the roaring arises from ulceration of the larynx. Ulceration of the trachea may exist without a sjonptom to suggest its presence. Even ulceration of some parts of the larynx may cause no roaring, but when the lesions are on the anterior portions — on the vocal cords, the free border of the arytenoids, or on the epiglottis — roaring results. Such a symptom occurring in an infected stud is most suggestive, and wherever it happens without an apparent cause the mallein test should be resorted to. An error in diagnosis may induce a practitioner to resort to tracheotomy ; this is attended by some danger to the operator. (Edema of Limbs. — In those cases of glanders which are first made evident by the appearance of lesions on the skin, swelling of the limbs is a common sjnnptom. We may have a localised swelling on the arm or thigh, resembling a bruise. There is qo history of injury and no sign of abrasion. The swelling is firm, irregular in shape, and slowly spreads. 84 SYSTEM OF VETEEINARY MEDICINE After a day or two, one or more small tumours or buds appear, and these rapidly suppurate. A general oedema of the limbs often accompanies the development of glanders, as it does other debilitating conditions. " His legs are filled," say the stablemen. This slight dropsical effusion is most notice- able below the knees and hocks, and may not be accompanied by any more specific symptom. In many cases, however, small spots become prominent and break, discharging a viscid fluid, which mats together the hair, and, running down the limb, leaves a track of dried brownish material, not unlike varnish, firmly adherent to the hair. In other cases oedema of the limbs is much more marked. As a rule only one leg is affected, and the swelling is extensive, rapid, and painful. We have all the appearances of an acute lymphangitis, extending high up into the arm or thigh. Not until some other lesions appear can we recognise this oedema as due to glanders. As a rule, we soon have development of " buds " on the inside of the limbs, which give way on the surface and allow of a discharge. One bud is followed by another along the course of the lymphatic vessels, so that in time one finds a series of lesions of different ages — some unbroken, some suppurating, some deep ulcers, and some healed or partially healed sores, with a few cicatrices. The mallein test enables us to diagnose these cases in the earlier stages, and the various developments of the " farcy buds " are them- selves quite indicative. It is necessary to remember that l3Tnphangitisi commences in the same manner, that epizootic lymphangitis may closely resemble the state I have tried to describe, and that another disease — ulcerative lymphangitis — ^is sometimes only to be differentiated by failure to react to mallein. Tumours.— There are two kinds of swellings seen in cutaneous glanders — ^the well-recognised farcy bud and a larger tumour. These larger tumours vary in size from 1 J to 3 inches in diameter ; they show no tendency to suppurate, and are very persistent. I have seen them remain for weeks, and, if the horse be permitted to Uve, they gradually decrease and finally disappear. If opened, their contents are found semi- gelatinous, and of a straw colour, rarely purulent. Their most common site is on the back and sides, less frequently over the gluteal region. They are round, and as prominent as would be the third of an orange laid on a flat surface. We seldom find more than one or two at a time on any horse, and they are usually widely separated from each other. It is worthy of note that these large tumours are never accompanied by any enlargement of the lymphatic vessels in their neighbourhood, GLANDEE8 85 whereas the ordinary " bud " is seldom seen without its accompanying " cord." The ordinary tumours — ^viz., the farcy buds — seldom exceed an inch in diameter. They may appear anywhere, but are most frequently seen on the fiace, neck, sides, and down the inner side of the Umbs. The appearance of one is usually rapidly followed by others, arranged in a row, and connected by a Unear enlargement, due to distension of lymphatic vessels, known as a " cord." These " buds " are first hard and prominent ; they rapidly soften, the skin gives way, suppuration takes place, and an angry ulcerating surface with a depressed centre and thickened margin is left. The discharge is almost oily in character, and dries into adherent masses on the hair below the sore. In a chain of farcy buds every stage of the lesion may be seen — a partially healed bud marking the place first affected, then one just broken, then one softening, and two or three more, diminishing in size, which are still hard. On the fine skin of the face they seldom exceed J inch in diameter, and when the ulceration stage is reached, they show very clearly the deep sunken condition, with thickened margins, which is most characteristic of sores in glanders. Hard Swellings, irregular in shape and varjdng in size, are not un- common in the early stage of cutaneous glanders. They appear on the limbs above the hocks and knees, on the sides, and on the sternum and abdomen. They vary in size, often reaching a measurement of 8 or 10 inches in length, and resemble a bruise rather than the enlargements of purpura. Swelling of Joints. — It is not common to find swollen joints in horses suffering from glanders, but in a few cases we have observed the rapid development of enlargements of knees and hocks, the latter joint present- ing a well-marked bog-spavin. Specific inflammation of bursse is also sometimes seen. I remember one case, in the days when farcy was not doomed to slaughter, in which bog-spavins and wind-galls were very prominent, and caused some stiffness for a week or two. The horse afterwards worked for a year, and these lesions entirely disappeared, but glanderous pleurisy ultimately killed him. Subacute Crlanders is the most common form of the disease seen in London. The temperature ranges from 102° to 104° F. The appetite is not lost, and the horse may remain at work without showing ill-effects other than fatigue and bodily wasting. These symptoms are often accompanied by an enlarged submaxillary gland, and later by a nasal discharge and visible ulceration. Acute Glanders is the term applied to cases in which the disease is 86 SYSTEM OF VETERINARY MEDICINE generalised, and the blood-stream invaded by the baoilU. The tempera- ture is 105° P., or higher ; appetite is lost ; respiration is rapid and accom- panied by snuffling or roaring ; the pulse is much accelerated ; a nasal discharge is seen from both nostrils, often tinged with blood ; and a cutaneous eruption or swelled legs may also appear. The horse dies in a few days from septicaemia and pneumonia. Chronic Glanders is the form in which some sjonptoms, such as an enlarged gland and slight nasal discharge, exist without much rise of temperature. These cases are now rare, but were common when com- pulsory slaughter was not enforced. They might develop gradually from a latent case, but more often followed a subacute attack, which had subsided after rest and treatment, in a horse of extra strong constitu- tion. Symptoms abated for a time, but few horses survived many months, and any violent upset to the general system, such as a dose of physic, excessive work, or the supervention of any acute disease, ended in rapid generahsation and death. These horses in olden times were separated from the stud and worked together. In double harness the pole of the vehicle was painted black, so that those who knew might be warned off. White states that he has known chronic glandered horses to work for two years before being killed. Chronic cases of the cutaneous form were formerly not infrequent. A horse with a thick leg and a few old scars resulting from an acute attack of farcy might work for weeks or months without much alteration. In cases favourably treated all the symptoms might disappear, but the rule was for the submaxillary gland to remain enlarged and hard. In time the marked limb sufEered again from an acute lymphangitis. Finally, the temperature rose, nasal symptoms appeared, and death followed. Well-marked cases of farcy sometimes show no pulmonary nodules at the autopsy, and frequently only two or three recent typical hsemor- rhagic centres. The greater number, however, are found to have nodules in the lungs of a form and structure which demonstrate that they have been in existence for months anterior to the cutaneous symptoms. Farcy lesions are nearly always secondary to disease in the lungs, and result from the escape of bacilli from pulmonary nodules, and their passage through lymph and bloodvessels to the skin. DIAGNOSIS. When a horse presents a nasal discharge, nasal ulceration, and an enlarged submaxillary gland, diagnosis is easy. A swollen leg and a typical chain of farcy buds is another form of the disease about which no doubt need exist. But there are many cases of glanders in which the GLANDEES 87 symptoms are not well marked, and there are some other diseases which at times closely resemble glanders. There are also cases in which the symptoms of glanders may be masked by the morbid changes due to other maladies. An Enlarged Submaxillary Gland may exist for some time before any other sign is apparent. This symptom may also arise from disease of teeth or sinuses, but usually is then accompanied by a unilateral nasal discharge with an offensive smell. An enlarged gland may be due to melanosis, which only occurs in grey horses, and is attended by no nasal discharge, but often by tumours in other parts of the body. Another rare cause of enlarged submaxillary gland is tuberculosis. In some unusual cases of glanders the submaxillary gland suppurates, and the condition may be mistaken for strangles, but the slow development of these cases should cause their true nature to be suspected. An injection of mallein assists diagnosis, and should be resorted to at once on the appearance of glandular enlargement. Strangles, Catarrh, and Influenza very often show a purulent nasal discharge,, which has been confidently credited as pecuHar to those diseases. It is not sufficient to observe the character of the discharge. Many cases of glanders commence with a purulent or semi-purulent discharge not distinguishable from that of other diseases. Some cases of latent glanders are wakened into activity by an attack of catarrhal fever. These are the cases which led to the error of supposing that "influenza turned to glanders." In young horses a nasal discharge may usually be accepted as innocent, but from an old horse should be treated with care. Newly-purchased horses from a town stud should always be suspected if they exhibit a nasal discharge, and the mallein test should be applied. Nasal Ulceration is almost diagnostic of glanders, but slaughter should not be adopted until mallein has been used, unless the character, of the ulceration or the presence of other symptoms are such as to leave no doubt. Nettle-Basil has been mistaken for cutaneous glanders. Although the swellings at first somewhat resemble farcy buds, their sudden appear- ance, their general prevalence over the body, and their tendency to coalesce, should be sufficient to found a diagnosis upon. The nettle-rash lumps disappear as rapidly as they make their appearance. Only once have I seen a case of acute glanders with the skin covered with lumps about the size of walnuts ; they were all about one size, and discrete. The horse was killed on other symptoms, and I considered the case one in which the two diseases coexisted. 88 SYSTEM OF VETERINAEY MEDICINE Purpura Haemorrhagica has often been mistaken for glanders. When the head is badly affected, we find swollen nostrils, a blood-stained septum, and a sanguineous discharge from the nose. These conditions may mask a case of latent glanders which has been generalised by the purpura. It is extremely difficult to open the swollen nostril in these horses suffi- ciently to see the septum. The swelling of the limbs may be mistaken for farcy of the legs, but as a rule farcy appears only in one leg, whereas the sweUings of the purpura are in two, or in all four, and in size and position bilaterally symmetrical. At the commencement of a case of purpura dark spots upon the septum nasi may suggest the use of mallein. The temperature is always raised^often high — so is useless as a reaction symptom. In almost every case of purpura, swelling at the point of injection is considerable, but as it rises in twenty- four hours, so it disappears in the next twenty-four, and its rapid subsidence in- dicates freedom from glanders. Laryngeal Disease may cause roaring in horses, and occasionally this symptom is the first to show itself in glanders. When roaring comes on suddenly, suspicion should be aroused, and the fact of its disappearance and recurrence should not permit a diagnosis of non-specific disease. The sudden access of roaring without any clear cause should be followed by an injection of mallein, especially in town horses or those newly purchased. Ulcerative Lymphangitis. — There is a form of lymphangitis which/ may be mistaken for farcy. In addition to the general dropsical enlarge-/ ment of the limb, we have a subcutaneous collection of pus, causing sloughing of a comparatively large portion of skin inside the thigh] Then the lymphatic vessels become enlarged and suppurate, and smaller abscesses form around and below the original lesion. These small abscesses are often very similar in appearance to farcy buds, but the ■ larger sloughs almost differentiate the two diseases. An injection of mallein affords the most rehable aid to diagnosis. Horse-Pox. — Some cases of horse-pox very closely resemble glanders on a superficial examination. They may have as symptoms a nasal discharge, enlarged maxillary glands, and small ulcers on the fine skin of the nose and lips. But there are other lesions not found in glanders— viz., vesicles, which soon form ulcers, on the mucous membrane of the lips. These ulcers are not like the malignant ulcers of glanders ; they are not so deep, show no tendency to spread, and soon heal. What is called Stomatitis Pustulosa Contagiosa is, I believe, only horse-pox (equine variola) under another name. When stomatitis happens to accompany lesions in the heel and back of the fetlock, no / GLANDERS 89 one disputes that the case is one of variola, especially if depilation follows, and the legs lose most of their hair. Stomatitis confined to the hps is communicable to man, and in two or three cases I have seen, the himian lesion from accidental inoculation was typically variolous. Botryomycosis. — ^Not often can this disease be mistaken for glanders. In one case in which some similarity existed there were two tumours on the inside of the thigh of the horse — one the size of a walnut, the other as large as a Tangerine orange. There was also an irregular, hard swelling on the antero-inferior aspect of the sternum. The tumours had been present for some weeks, and had suppurated. The swelhng on the breast had just appeared, and this led to doubt of the nature of the case. Mallein was injected, and gave no reaction. Afterwards Sir John McFadyean cleared up the mystery by discovering the botryomyces.' Epizootic Lymphai^itis is now a non-existent disease in Great Britain, but in some countries it is prevalent. There are cases of the disease which only the most experienced practitioners can distinguish from the cutaneous forms of glanders. The mallein test should be resorted to at once, and the negative results should be followed by a microscopic examination of the pus from the sores, so as to obtain a positive diagnosis. This is reached by the discovery of the lemon-shaped causal organisms of epizootic lymphangitis. Aids to Di^nosis. There are many methods suggested for verifjdng a diagnosis of glanders. The microscope may be used to show the bacilli in the pus or juices of a suspected lesion. If a man is expert in using the micro- scope and in staining preparations, he may identify the organism, but in the majority of cases a practitioner would be well advised to leave this method to the trained bacteriologist. The agglutination test is another means of assisting diagnosis which is only useful in the hands of an expert. Inoculation of other animals, such as horses, asses, or guinea-pigs, may also be adopted, but it is expensive, and requires time for develop- ment. Inoculation into a susceptible animal gives positive demonstra- tion if active bacilH are present in the material used for injection. The discharges from any visible lesion are, however, mostly contaminated by mixed organisms, and sometimes wanting in active glanders bacilli. Inoculation of pus from the nose into the larger animals has often failed to give a definite result ; and even separate nodules from one pair of glandered lungs which appeared morphologically aUke have given some negative and some positive results when singly inoculated into guinea- pigs 90 SYSTEM OP VETEEINARY MEDICINE Cultivations of the bacilli are not easily carried out unless a tolerably pure material can be obtained. The discharge from the nose, or from an ulcer on the skin, contains so many other organisms that it is useless for culture purposes. When an unopened farcy bud exists, material can be obtained by incision which, in skilled hands, may afford good results from cultivation on steriHsed potato. All these aids to diagnosis are of use in their degree, but they can only be carried out by a bacteriologist in a laboratory. The general practi- tioner will find injection of mallein quite as trustworthy, much simpler, and more prompt in its indications. Mallein was discovered in 1891 by Kalning and Helman, two Russian veterinarians. It is obtained by growing the BacUlus mallei for some weeks in a suitable medium and at a definite temperattire. The resulting virulent culture is then heated in an autoclave, to kill all the organisms, and filtered through a porcelain filter to remove the dead bacilli. To the material thus obtained is added glycerine and a solution of carbolic acid. Mallein so prepared is a transparent fiuid of a pale yellowish-brown colour. If injected under the skin of a healthy horse in small doses, it produces no symptoms, save, perhaps, a swelling the size of half a walnut at the spot of injection. This swelling, which soon disappears, may be due to a dirty skin or a dirty needle, to mallein which has been allowed to become dirty, or even to too large and blunt a needle. When in- jected into a horse suffering from glanders, two effects result : a rise of the general temperature and a swelling at the seat of injedion, which together constitute a specific reaction. This double reaction renders mallein more useful than tubercuKn as a diagnostic agent, because in many cases of suspected glanders and tuberculosis an abnormally high temperature is present. The elevated temperature in the tuberculosis case renders tubercuUn useless, but, with a high temperature in glanders, we may still obtain some indication from the presence or absence of a local swelhng. It is inadvisable to use either agent where the tempera- ture is abnormal ; but we may have to wait days for the temperature to reach the normal, and when diagnosis is urgent, mallein may be employed with hope of some guidance. Mallein is injected under the skin in doses of 20 drops or less, by means of a hypodermic syringe. Any part of the skin may be selected, but the best is the side of the neck, about halfway from the ear to the shoulder Injection over the shoulder or ribs results in a needlessly painful swelling. Injection into the skin of a leg is followed by great lameness, if a reaction takes place ; and injection into the loose skin in front of the stifle causes a swelling, easily felt, but not very visible. The neck as the site for GLANDERS 91 injection has other points in its favour — the skin is easily hfted into a fold, the operator is in a good position if the horse is bad-tempered, and the swelHng of a reaction is well thrown up by the firm tissues underneath. Most of the needles supplied with veterinary hypodermic sjrringes are too long and too thick. The finer the needle, the more easily is it in- serted, and the less the horse resents it. There are two forms of junction between needle and syringe — ^the screw and the plug. The screw is objectionable, as the needle can only be used Tvith the syringe attached, and when the horse is fidgety or spiteful th« operator may have his choice between leaving the syringe hanging from the neck by the needle, or keeping his hold and being injured. The detached needle is easily inserted, and remains in place if it has to be left ; whilst the syringe with the plug junction is used with the greatest facility. There are certain precautions which should be observed in the appUca- tion of a mallein test. The first is to take the temperature of the animal before an injection is made. In a working stud of fifty horses it is quite usual to find a horse, apparently well, with a temperature of 104° F., and as this may be the commencement of an illness which would lead to even a higher temperature, that animal is left over for a further test. "When the injection is made without taking the temperatures, such cases are only discovered when the reaction is looked for, and the error is unavoidable of considering the rise a sign of general reaction, whereas it has nothing to do with the mallein. Of course, the syringe used should be surgically clean, and the mallein should be clear and without sediment. How long mallein will keep good and active is not, perhaps, known ; kept under proper conditions, certainly six months, and probably a year. But it is best to obtain fresh supphes, and these can always be in amount just sufficient to cover probable demands. Directions to wash and disinfect the skin of the neck before injecting are usually given and obeyed in practice. I consider this a waste of time, and my experience is that if the skin be dry the results are invariably good. When the temperature of a horse is normal, and a subcutaneous injection of maUein is made, we have a double reaction as an indication that he is infected with glanders. We have a rise of temperature of 2° or 3°, or more, and we have a local swelling at the site of injection 4 inches or more in diameter. The rise of temperature commences about seven hours after the injection is made, and continues to increase up to about the sixteenth hour. If the horse be infected, the temperature may remain high for some hours longer, and in a few cases for some days. Diameter of Local Swelling. . . 100° F. . . 104° „ 3 inohes. . . 105° „ 4 „ . . 105° „ 5 „ . . 104° „ .. 6 „ 92 SYSTEM OF VETEEINAEY MEDICINE The following is a typical reaction : Temperature. At 8 p.m. (time of injeotion) „ 8 a.m. (12 hours after injection) „ 12 noon (16 ,, „ ) „ 4 p.m. (20 „ „ ) „ 8 p.m. (24 „ „ ) The local swelling develops gradually, and, when specific, increases in size for over the twenty-four hours following injection. Very little value attaches to the vertical measurement of a swelling, which results from the effusion gravitating. The typical swelling is round, raised well above the surrounding skin, painful on pressure, but, above all, one which increases in diameter after the twenty-fourth hour. Although I accept a mallein reaction as specific of glanders, I must acknowledge that an ideal double reaction is not always given. Some- times the rise of temperature is less than we consider indicative, whilst the swelling is typical. At others the swelling is too little to offer any guidance, whilst the temperature is typically high. A temperature rising from normal to 105° F., with a swelhng 6 inches in diameter, is an indication of glanders upon which slaughter may be safely advised. In an infected stud I should also accept a temperature of 104° F. -with a 4:-inch swelling which increased or remained after the twenty-fourth hour, as signs of infection ; so should I regard a temperature of 103° F. with a 6-inch swelling, or a temperature of 105° F. with a 3-inch painful swelling. There are imperfect reactions which render it difficult to draw a hard-and-fast line as to when a reaction may be positively accepted as indicative of glanders, and these have a very practical bearing now that the law recognises reaction to mallein as equivalent to " diseased." As the exact time after injection at which the double reaction reaches its maximum is not definite, it becomes important to know when the horse should be examined, his temperature taken, and the swelling measured. I do not think any useful information is missed by not visiting the horse after injection until sixteen hours have elapsed. In a few cases the temperature may rise to 105° F. by the sixteenth hour, and fall to 104° F. by the twenty-fourth, but that register is quite sufficient if the swelling is indicative ; and as the swelling in an affected animal goes on increasing after the twenty-fourth hour, it is advisable not to make the concluding visit too early. There are very few definite reac- tions which need for their recognition more than one visit after injection, and that should be made on the twenty-fourth hour. To read the double reaction of mallein most accurately — to recognise the maximum tempera- GLANDERS 93 ture and see the full quantity and quality of the swelling — we must take the temperature at the time of injection, again at the sixteenth hour, and again when we examine the swelling at or just after the twenty-fowth hour. The really indefinite reactions — ^temperature under 103° F., and swelling less than 4 inches — ^must be tested again, and this may best be done after a period of two or three weeks. I fix this time as the best, but I have seen perfect reactions when the injection has been repeated in a week. In cases which have reacted to mallein, a second test often shows a typical swelhng, but a reduced rise in temperature. Here the swelling may be accepted as indicating disease, even if the temperature is only 103° F., or even a degree less. There are a few exceptional cases in which a rise of temperature occurs within twenty-four hours, with no swelling, but in the next twenty-four hours a typical swelhng develops. These cases are infected, and the possibihty of this delayed local reaction shoidd make us careful not to pronounce a horse free from glanders, if a rise of temperature has occurred, before the lapse of forty-eight hours. It is inadvisable to make a mallein test of a horse with a temperature over 102'5° F. In cases where diagnosis is urgent, and we test an animal with a temperature of 103° F. or higher, &jdll of 2° in twenty-four hours is a suspicious sign which may be considered in conjunction with the local swelling. I have seen some reactions to mallein which were apparently mis- leading. I have heard of others from good observers. These results force one to acknowledge that the use of mallein is only an aid to diagnosis. There are cases in which mallein has failed to reveal any specific lesions. There are also cases in which mallein has failed to give a reaction, whilst a post-mortem examination has disclosed definite glanders lesions. These misleading results are few and far between. When a stud of horses that has been infected for some time is tested with mallein, we expect to have a^ number of animals give a reaction, and a few to show an indefinite reaction. These latter are retested in ten to fourteen days, and those that react are killed. After this it is supposed that the stud is clear, but it is not uncommon to find another case or two to develop cHnicaUy in the course of two or three months. The probable explanation of this is that the disease must reach a certain stage before it is indicated by mallein. Nocard infected a horse by ingestion of glanders bacilli, and injected mallein on the seventh, four- teenth, and twenty-first days after. No reaction was given until the third test was made. If this experiment may be accepted as generally applicable, horses infected seven days before being injected with mallein 94 SYSTEM OF VETEKINAEY MEDICINE would give no indication of their infection. In some horses experi- mentally infected by Sir J. McFadyean, a reaction to mallein was given thirteen days afterwards. "We should probably be certain to detect all infected by repeating the test in any stud after the lapse of fourteen days. In a stud from which a number of clinical cases has recently been removed, the possibility of these undiscovered infections warns us that a retest of the whole should be adopted if we desire to be quite certain that no disease remains. A safe rule to adopt is : When in doubt, repeat the test. No one asserts that mallein is infallible. It is to be accepted as an aid to diag- nosis, and its reactions considered with the history and surroundings of the horse. But it is an aid far more reliable than any other, more trustworthy than g,ny expert opinion, and indicative when no trace or sign of disease can be detected by the most careful clinical examination. PREVENTION. The prevention of glanders requires intelligent action upon the part of horse-owners with reference to their premises and their studs. It also requires well-considered regulations to be enforced by all local authorities, and supervision over the whole by a central body, such as the Board of Agriculture. In Great Britain the Diseases of Animals Acts are administered by a central authority — ^the Board of Agriculture — assisted by local authori- ties. The owners of stock and their private veterinary advisers also play an important part in co-operating, or otherwise, with the authori- ties. The discovery of disease is a matter antecedent to all preventive action, and the owners or their veterinary surgeons must be trusted to make this discovery first, and then to notify their suspicions. The prevention of all the scheduled diseases, as well as those not yet scheduled, must commence in the stable, field, or shed. It is apparent, then, that, so long as glanders prevails around us the most careful owner of horses may be unable to protect himself against infection. He may introduce the disease by a new purchase suffering from the latent stage of glanders, or he may have one of his old horses infected through the mangers or pails used in another stable by a diseased horse. The owner who has a large stud, and has to make frequent purchases to maintain it in working order, may guard himself against the introduc- tion of disease by the new horse suffering from latent infection, by testing with mallein every new purchase soon after its arrival. No one can GLANDEES 95 absolutely provide against contagion if his horses cohabit with others that are infected, and therefore it is the interest of all horse-owners to assist in stamping out the disease throughout the kingdom. The man who buys cast horses from large studs, or who buys at sales, should always test every new purchase within twenty-four hours of receiving it into his stable. If it reacts, he can demand the return of his money when a warranty of soundness has been given, but in no other case. At the worst, he protects the rest of his horses from infection, and probably may be able to come to some compromise with the vendor. If it became a general practice for horse-buyers to test their new pur- chases, the custom would have a most beneficial effect in preventing the spread of disease, because owners would then hesitate to sell any horse which would, if diseased, be detected at once by the purchaser. When a stud is already infected — and many in London have been so for fifty years — the most essential preventive action is to find out which horses are diseased. This can be done by applying the mallein test to the whole. To make doubly sure that no infected horse has escaped detection, the test should be repeated in six or eight weeks. All that react must be separated from the healthy, and slaughtered. With a large stud stabled in widely distant depots, the full value of testing with mallein may be lost through carelessness in changing horses from depot to depot. A horse moved from one stable to another without having been first tested, may carry disease and spread it widely before being detected. An oversight of this kind has been the means of rein- fecting more than one stable. Turning horses out to grass — at any rate, on farms round London — has been a fruitful source of infection. Horses from different stables run together, and there may be as many as twenty or thirty horses in one set of meadows. I knew a case in which eighteen horses were attacked with glanders within four months of being at grass. The infection was traced to one old horse not worth £10. The owners of pastures round London should admit no horses to their fields unless from a knowil clean stable, and after a test with mallein has been made. London horse- owners would be well advised not to turn out their horses, except with a guarantee from the farmer that no strange horses are allowed to run with them. It is evident that whenever horses are collected together in numbers from various places, there is a chance that an animal suffering from latent glanders may be among them. The accommodation at large fairs and race-meetings favours infection spreading if a diseased horse should happen to be present. Military mancEUvres have often helped to spread 96 SYSTEM OF VETERINARY MEDICINE glanders, not by infection from the well-looked-after army horses, but by a diseased animal introduced with the mixed lot supplied by contractors. War always spreads glanders among the troop and transport horses, but the spread does not cease with the war. Economy suggests the sale of superfluous horses, and thousands of infected animals are in this way scattered over the whole country in which the war took place. Since mallein became available for testing horses, the dissemination of glanders by sale of cast horses is no longer excusable, and I am glad to say that in South Africa very great care was taken to guard against the sale of infected animals, thousands of doses of mallein having been used to protect stock-owners who bought the superfluous horses. One of the most important preventive measures to be taken by authorities engaged in stamping out glanders is to trace back the history of infected horses, and attempt to discover the source of their infection. The relation of a concrete case or two will make this point clear. A glandered horse is found in a cab-yard, and the owner states that he has never before had any cases of the disease. The history of the horse is that he was purchased at a sale ten days before he was noticed to be ill. At the sale-yard the name and address of the vendor are obtained, and his stud is inspected. It consists of seventeen horses.. One showing slightly suspicious symptoms is tested with mallein, reacts, and is killed. The post-mortem reveals old glanders lesions. Then the remainder of the stud is tested, and five horses react, which are found glandered on post- mortem. From the first case we were able to find six dangerous animals, and put a stop to further infection. A dead horse is found in a knacker's yard with glanders nodules in the lungs. On going to the stable from which he came, there are seen eight horses, none of which show any clinical symptoms of glanders, but all are rather poor in condition and aged. The lot were tested, and every one reacted, their infective condition being proved by post-mortem examination. A horse in a well-managed stud was found affected with farcy. The animal had been there two years, and no case of glanders had been seen in the stud. The history of the horse included two months at grass for lame- ness, and he had only resumed work about a month. The field was in another authority's district, so application was made to the veterinary inspector of the district, and he repUed that he had seen four cases of glanders on the farm at which the horse had been grazing. When the spread of infection can be traced to its source, an un- notified outbreak is often discovered ; it may or may not be one known to the owner. GLANDERS 97 One of the cases I have referred to was discovered in a knacker's yard, and if these places were inspected by the veterinary surgeons of all local authorities, as they are in London, many cases of glanders would be found that now escape detection. It has been suggested that pubhc sales and auctions should be in- spected by the official veterinary inspector. If clinically diseased horses were ever sold there, inspection would be valuable ; but they are not. The horses entering every horse repository in London are examined by the auctioneers' private veterinary surgeon, and very strictly examined. The horses coming through repositories that help to spread glanders are those in which the disease is latent, and may remain latent for a long time. To inspect these and pass them would inspire many buyers with a sense of security that was more apparent than real, and when the latent disease developed shortly after purchase, the same class of buyer would feel great contempt for the inspector who had not discovered that ' the horse was infected. Disinfection and cleanUness are enforced by law in all stables which, have been the scene of a glanders outbreak. This appKcation must not be confined to the mangers, walls, and floors. Nosebags, pails, and stable utensils must all be disinfected, if not destroyed. Rugs and halters, if they are worth saving, may be soaked in a solution of carbolic acid and hung to dry in the sun for a day or two. Before any disinfec- tion is done, the place should be made as clean as possible. Mangers, must be emptied, and, with the stalls, walls, and bales, soaked with a few paiKuls of water overnight ; then hot water and soda appUed with a brush until the grain of the wood is visible. After a day or two to dry, the walls, etc., may be dressed with hot limewash. The floors and manure are best treated with dry quickUme. Of course, no prevention of glanders is real which does not aim at stamping the disease out of the country. This means the slaughter of every case as soon as it is diagnosed. Before maUein was discovered, it would have been a long and expensive task to have cleared the country of glanders. By the use of mallein we may now clear all infected studs, but it must be remembered that the most careful use of this agent will not always indicate every infected horse by one testing. Professor Bang long since pointed out, in the case of tuberculosis, how herds which had been tested with tubercuhn, and from which all reactors had been removed, when retested a few months later disclosed a small percentage of infection which had escaped the first test. A similar experience is found with glanders, and is likely to be even more noticeable in stables from which animals that give an indefinite reaction VOL. I. 7 98 SYSTEM OP VETERINAEY MEDICINE are not removed. It is well to remember this, because the expectation of an easy and prompt clearance of disease from a large stud may lead to disappointment, and both owners and" officials become disheartened and sceptical. The stamping out of any disease is a laborious process, and mistakes are certain to occur. Every mistake may give rise to a fresh outbreak. The Order of 1907 will, I believe, prove successful, but local authori- ties would do well to arrange with the owners of large studs which are V supposed to have been freed from disease by.mallein- testing and slaughter, for a second test of all horses a month or two after the slaughter of the last reactor. Importation. — Considering the trouble and expense devoted to clearing our home stock, it is right that provision should be made against the introduction of glanders from other countries. The new Order imposes a very mild regulation upon horses, asses, and mules^-they shall not be landed unless accompanied by a veterinary certificate to the effect that they show no symptom of disease. ' Experience proves that not much risk is run by importing a good class of young horse, but a few infected horses have arrived, and others may arrive. When we have cleared our own studs, the Board of Agriculture will probably enforce the use of the mallein test upon imported horses. State legislation for the control or suppression of glanders is neces- sary, because the efforts of individuals can only apply to their own studs. After prolonged and expensive action, a horse-owner may be successful in stamping out the disease in his stables ; but when glanders is allowed, to prevail around him he is never safe, and sooner or later is almost certain to again find his stud infected. Legislation should not be all penal. With penalties for offences it should combine rewards for assistance. It is a misfortune, not a crime, for a man to have his animals affected with glanders. To get rid of the disease, legislation must interfere with his use of horses which may be of great intrinsic value to him and of no injury to his neighbour. It must destroy horses which present no sign of disease, and which, though in- fected, may never become infective. To meet these cases compulsory slaughter of stock should be accompanied by monetary compensation. The argument for compensation in cases where legislation is directed, with probable success, to eradicating a disease from the country is not on the same level as a claim for trade losses due to unpreventable acci- dents. These accidents will occur again, no matter what care and cost is expended on them. But success in stamping out disease ineans the permanent freedom from the loss caused by such disease, and therefore GLANDERS 99 a national loss is saved which far exceeds the national contribution in the form of compensation. Legislation must not be in advance of intelli- gent pubUc opinion. If it is, there is resistance, active or passive, which renders the regulations a failure. When owners of stock acknowledge the value of legislation nearly everyone interested co-operates, and success is assured. There are, of course, always some owners who will attempt evasion, and a few who wilfully spread disease by moving or selling diseased animals. For such penal clauses are requisite. Legisla- tion fails in its object when weak half -measures are adopted. Their want of success, with the accompaniment of hardship to owners from rigid restrictions, brings the whole of the legislative measures into dis- repute. In 1899 a Departmental Committee was appointed by the Board of' Agriculture, with Lord Stanley as Chairman. It took evidence and issued recommendations. Still legislation remained the same, and it was not till 1907 that a new Order, based on the 1899 Committee's sug- gestions, and in accordance with modern veterinary science, came into force. The recommendations of the Committee were as follows : 1. That the Board of Agriculture should exercise a more extended supervision of the working of the Glanders or Farcy Order. 2. That the Glanders or Farcy Order should be amended to permit of notification of disease being made either to a constable or a veterinary inspector. 3. That where practicable the local veterinary inspector should not engage in private practice . 4. That it should be made obligatory for veterinary surgeons to notify cases of glanders of which they become aware. 5. That occupiers or owners of knackers' yards should notify any case o£ glanders found in animals taken to their yards for slaughter. 6. That horses that react to the mallein test should be considered as possible sources of infection. 7. That horses that the Veterinary Inspector may consider to have been exposed to contagion should be dealt with in the same manner as suspected horses, but with certain reservations. 8. That the slaughter of all animals showing " clinical " symptoms of glanders should be made compulsory. 9. That compensation for horses slaughtered solely on account of reaction to the mallein test should be on a higher scale than that for a " clinically " diseased horse, with a limit of £25. But in the event of no glanders lesions being found post mortem, the compensation should be the full value, with a limit of £50. 100 SYSTEM OF VETERINARY MEDICINE 10. That the Board of Agriculture should conduct experiments with regard to the use and influence of mallein. . By 1905 the Board of Agriculture had really grasped the facts of the case, and tentatively drew a new Order. Then the Board endeavoured^ to obtain some financial assistance from the National Treasury, knowing that any earnest attempt to stamp out glanders would be attended by expense — greater expense than could honestly be inflicted upon local rates. The Treasury declined to assist, and in 1907 the Board issued a new Order, leaving local authorities to do the work and pay for it. GLANDERS IN MAN. In man glanders appears in two forms — acute and chronic — but either may be a sequel of the other. When acute glanders does not c^use death in three or four weeks, the patient may linger on with the chronic form, showing itself by more or less active lesions, which some- times heal, but more often reappear in different parts of the body. A very few cases seem to recover. The period of incubation in man is usually short — from two to six days. There are recorded cases in which symptoms have not appeared until months after the patient has ceased to have any connection with horses, and these are probably cases in which the disease has run a latent course. The symptoms of an acute case are high fever, headache, and pains in the limbs. These may be the only manifestations of disease for a week or more, and then a cutaneous rash appears in the form of nodules,- which rapidly break down into ulcers. Frequently this rash is not visible till a day or two days before death, and the patient dies of acute septicsBmia, with few or no local lesions. / 1 quote some reported cases showing how protean are the forms of human glanders. Two cases were reported in the Lancet by Dr. Groodall : A man, aged fifty-five, a printer, was admitted into the Eastern Fever Hospital on October 28, 1903. He had been seized with shivering and pain in the limbs on the 9th. On the 11th he was worse, and was medically, attended at home till the 20th. On that date he went as out-patient to a general hospital whence he was sent as a case of typhoid fever to the Eastern Hospital. On admission he was semi-comatose. On the skin were a number of small superficial pustules, most abundant on the chest, right leg, and right forearm. There were a few on the left cheek, the back, left thigh, and left upper arm. Besides these pustules, there were several swellings of varying size in different places— one on the right GLANDERS 101 frontal eminence, two on the right forearm, two on the left forearm, one on the right leg, and one on the left. The largest swelling fluctuated, the smaller did not. Some appeared to be in the subcutaneous tissue, others were distinctly in muscles. There was no discharge from the nose. On the morning of the 30th the contents of a swelling on the right leg were drawn off and microscopically examined. A bacillus resembling that of glanders was at once detected. The patient died on the 31st. The second case was that of a stableman, who was taken ill with " pains all over him" ten days before admission. He was sent to a general hospital as a case of blood-poisoning, and then to the Eastern Hospital as one of typhoid fever. In one of the muscles of the left forearm was a nodular swelling. The left knee-joint was much swollen, very painful, and distended with fluid. The patient said that the lump in the arm had been present since February 18, and the knee-joint had been affected since the 16th. Next day an examination of fluid from the knee and arm was made, but no organisms were found. Cultivations in agar were made, and on the second day what appeared to be the Bacillus maUei was detected. A day or two later Drs. Lewis and Wood obtained the bacillus from the fluid of the knee-joint. The patient died delirious on March 11. An inquest was held at Westminster on August 15 on Albert Allen, a horse-keeper in an omnibus-yard. Dr. Cope saw the patient first on June 12, when he showed symptoms of an ordinary cold, with aching of the limbs. He was treated for a rheumatic attack. On the 19th there was a nodule on the leg, and some inflammation of the limb. Oh July 12, other nodules appeared on the right arm, and on the 13th the man was taken to Westminster Hospital. Mr. Frank Mott saw him on the 14th, and as there was a suspicion of glanders, some pus was examined and the Bacillus mallei discovered. The man died August 11. An autopsy revealed eleven abscesses scattered over the arms and legs. There was pus in the knee-joint. Nothing was found in the nose, throat, larynx, or trachea ; but in the lungs some small nodules about the size of a pea were discovered. In a note published by Drs. Bullock and Twort, of the London Hos- pital, the first sentence is : " Glanders in man is generally believed to be uncommon, although, no doubt, the belief is partially due to the protean characters which the disease manifests clinically, and which render it difficult of diagnosis." They then give details of six cases which had come under their notice at the hospital, and of a seventh case which was of doubtful character. Four of these, cases were chronic, had been treated 102 SYSTEM OF VETERINARY MEDICINE as syphiKs, and were characterised by recurring abscesses and throat ulcerations which lasted for months. Inquest on Charles NichoUs, a horse-keeper, at Westminster, May 19, 1905 : On May 1 the man complained of illness, and saw a doctor, who said he had pleurisy. Two or three days later he was taken to St. George's Hospital, where he died on thei 16th. Dr. Hunt said he had diagnosed the case as rheumatic fever. Dr. Etherington, House-Physician, said the deceased on admission seemed to be suffering from rheumatic fever. The day before death it was thought to be glanders, and a post- mortem examination verified the diagnosis. From the Lancet of April 1, 1 take the following from a report by Mr. M. J. Cromie, House- Surgeon, Westminster Hospital : A horse-keeper, aged twenty-five, was admitted on November 12, 1904. A consultation between Dr. Hebb and Mr. Spencer led to a surmise that the patient wasi suffering from glanders. On the following day Dr. Hebb found the Bacillus mallei. The patient died thirty-three hours after admission. " A full consideration of the case exposes possibilities of infection, and of such cases being overlooked," is Mr. Cromie's comment, and the history more than bears this out. On November 3 he had pain and swelling of the left side of the face, and was advised by a dentist to bathe his face in hot water, as an abscess was forming. He next saw two other medical men, who told him that he had celluhtis and erysipelas. On the 9th small hard lumps began to appear in the neighbourhood of the joints, with pain in the joints, especially the knees. On this day the patient went to a hospital, and on his out-patient paper was entered " Cellulitis of the face." An incision was advised, but as he could not be admitted, and felt very ill, he declined it. On the 10th the nodular swelhngs became red and inflamed, and pustules appeared on the swollen face, the hps, and the buccal aspects of the lips and cheek. The lips became black, nasal discharge commenced, and dyspnoea supervened. He was therefore taken to another hospital, when he was given a paper saying he was suffering from cellulitis and cephalitis {sic). Finally, he was taken in an ambulance to the Westminster Hospital. The post-mortem examination showed abscesses in the muscles all over the body. The mucosa of the nose and sinuses was much swollen, but there was no ulceration of the nasal membrane. The lungs were engorged and the seat of numerous abscesses. An inquest was held at Hammersmith in November, 1893, on William Wallace, a horse-keeper. The widow stated that towards the end of September the deceased told her he had been bitten by a horse, and about a week later he complained of severe headache. Following this GLANDERS 103 came pain in the arms and legs, and on October 7 he went to a dispensary. The pains increased, and on October 14 he went to the West London Hospital, when he was told that he was suffering from rheumatic fever. He was admitted into the hospital on the 18th, and died on the 24th. Dr. Wilks, the House-Physician, said the case was of a very doubtful character, and it was not till the 23rd that a diagnosis of glanders was made. I think it may be concluded that two symptoms which have been trusted to are not often prominent— a recognised spot at which inocula- tion has taken place, and the nasal ulceration and discharge. The symptoms which are most suggestive are the combination of high fever, a cutaneous rash, and pains in the muscles and joints. It is remarkable how seldom any direct evidence of inoculation through the skin is given in recorded cases of human glanders, although a wound is always expected and looked for. I venture to suggest that too much credence has been given to the idea that man is generally infected by inoculation. Horses are almost always infected by ingestion of contaminated food, and there seems no reason to believe that a similar method of infection may not take place in man. The habits of some stablemen are careless in the extreme, and I have frequently had to tell men who had handled the pus-covered nostril of a glandered horse to go and wash their hands. They were quite satisfied to wipe the contaminated hand on the seat of their trousers, and then resume their meal of bread and beef, or bread and cheese. Experimental inoculation of glanders through the skin and accidental infection of a wound always cause local primary sores, and usually some lesions of the nearest lymphatic vessels and glands. We might expect that inoculation of the.face and hands of man, if it occurred, would give rise to local lesions, and we know in cases where the wound and its infection are evident that marked local lesions do occur. The eruption that appears on man, usually a day or two before death, soon forms sores or ulcers ; but these lesions are secondary, and their occurrence on the face does not prove that they indicate the site of inoculation. The ten days' illness which often precedes any local lesion must have been due to glanders infection, and any inoculated spot would have given evidence of morbid change at least as early as the access of the febrile symptoms. The fever, high temperature, and muscular pains, which exist for days without a skin lesion, are most suggestive of infection by ingestion. Glanders in man is such a loathsome and fatal disease as to deserve 104 SYSTEM OF VETERINAEY MEDICINE more attention than it receives. Probably, if all cases were recognised, the mortality would be equally heavy, but prevention would be more actively assisted. If the medical profession called for the suppression of glanders as loudly as they did for the extermination of rabies, prevention in all animals would be accelerated. Glanders has recently been scheduled as an industrial disease, and payment of compensation to infected employes by the owner of diseased horses follows. This ought to be more widely known, and the fact would lead to greater care. The Glanders Order of 1907 required notification by the local in- spectors to the Medical Officer of Health of the district in which the disease is found. This regulation is of little value, as any infection of man has taken place before the notification is served. If the Medical Officer of Health forwarded his information to the medical practitioners in his district, it might do some good by directing their attention to possible infections, and thus, perhaps, lead to an early diagnosis of other cases in man. Finally, I would suggest that glanders should be included in the list of human diseases which are subject to compulsory notification. TUBERCULOSIS By E. WALLIS HOARE, F.R.C.V.S., and J. S. LLOYD, F.R.C.V.S., D.V.S.M. Synonyms.— Consumption ; Scrofula ; Pining ; Grapes ; Pearl disease ; Phthisis pulmonaHs ; Tabes mesenterica. French: Tuberculose; Pommeliere ; Phtisie calcaire ou pul- monaire. German : Tuberkulose ; Tuberculose ; Perlsucht. Definition. — ^A contagious and inoculable disease affecting all species of animals, and also man, and caused by the Bacillus tuberculosis. The lesions are characterised by the presence of small tubercles in various organs of the body, or of diffuse infiltrations of tuberculous tissue, all of which tend to undergo certain degenerative changes, such as caseation, calcification, ulceration, and sometimes fibroid degeneration. GENERAL REMARKS. Tuberculosis is a disease of the greatest importance, not only from the fact that it causes serious losses to owners of cattle, but also, owing to its marked prevalence amongst the bovine species, there is a grave risk of the affection being communicated to mankind through the inges- tion of the milk and meat of infected animals. The relation between animal and human tuberculosis has been studied for many years. Although Koch believed that infection of human beings from the above source was of rare occurrence, the consensus of opinion amongst medical authorities is that bovine tuberculosis is communicable to man ; hence active steps should be taken to eradicate as far as possible the disease from cattle, and to secure efficient inspection of the meat and milk supply. Tuberculosis in animals has been extensively investigated in many countries, and is still engaging the attention of scientists. These re- searches have resulted in not only a clearer perception of the etiology and pathology of the disease, but also in the adoption of preventive measures which are likely to prove of far-reaching importance. 105 106 SYSTEM OF VETERINARY MEDICINE The discovery of the tubercle bacillus and of tuberculin must be regarded as anaongst the most important achievements in the history of the disease. History. — Tuberculosis appears to have been recognised from the earliest times. According to Kitt, the communicability of pulmonary consumption was suspected even by physicians of antiquity, including Hippocrates and Isocrates, and also by some of the laity. According to Nocard, human phthisis is said to have been declared a contagious disease in one of the Gothic Laws. The risk of ingesting the flesh of tuberculous animals was evidently recognised at a very early period, as rules against using the flesh of animals suffering from " wen or scurvy " occurred in the Mosaic Laws, also in the Talmud, and especially in the Mischnal (third century), while in the Gemara (fifth century) are found enactments of a similar nature, the terms " kandi " and " timari " probably referring to tubercle. (Friedberger and Frohner). In the ninth century in Germany the Franks had ecclesiastical laws forbidding the use of the flesh of cattle and pigs affected with tuberculosis of the serous membranes. Laws were also enforced in various parts of Germany on the same subject between 1370 and 1582 ; but in 1783 the Berlin Board of Health declared that the flesh of tuberculous animals was fit for human food. In 1816, however, rules for the inspection of meat were laid down by Tscheulin, in which only under certain conditions was the flesh to be condemned, and a similar procedure was adopted in several other countries on the Continent.* In 1702, tuberculosis in cattle was erroneously identified with syphilis in man, and this view was adopted up to 1783, the term " French disease " being given to the affection, and compulsory slaughter of infected cattle was enforced in Prussia and Germany. When the duality of these diseases was accepted, the restrictions oh meat inspection, as already mentioned, were withdrawn by the Berhn Board of Health. In 1774, RuhUng of Gottingen regarded tuberculosis as a contagious disease in cattle, and Huzard and other observers in France, about 1790, believed in the identity of human phthisis and bovine tuberculosis. In 1831, Giirlt pointed out the similarity of the lesions of tuberculosis in man and in cattle, while Spinola, in 1858, beUeved the two affections to be identical. Other observers, however, held the view that the disease in cattle was distinct from human phthisis, and even doubted the contagioug nature of the affection. * Op. cii. TUBEEOULOSIS 107 The first important confirmation of the contagious character of the disease resulted from the inoculation experiments of Villemin in 1865. By means of inoculating human tubercular matter into animals he demonstrated that tuberculosis was an inoculable infective disease, and stated that the affection in man and in cattle was identical. St. Cyr, Chauveau, Gerlach, Klebs, and others, conducted extensive feeding experiments from the year 1868, and demonstrated the trans- missibility of tuberculosis by means of infected food. Koch, in 1882, discovered the specific bacillus of the disease— the Bacillus tubercvlosis — and considered this micro-organism to be identical in man, cattle, and fowl. During the same year EhrHch directed attention to the special staining properties of the bacillus. In 1884, after fresh studies, Koch reaffirmed his former conclusions, and found the specific micro-organism in tuberculosis of the ox, horse, pig, goat, monkey, rabbit, guinea-pig, dog, cat, fowl, rat, and mouse. Rivolta, in 1889, pointed out that marked differences existed between the bacillus of mammalian origin and that of birds. Later researches by Nocard and others showed that in reaHty these differences were very slight, and that by a series of passages through certain animals the bacillus of the mammalian type was identical with that of the avian variety. In 1901 Koch retracted his earher opinion, and stated that, as the result of his later experiments, he could only conclude that human and bovine tuberculosis were distinct affections, and consequently the in- fection of human beings from the ingestion of meat and milk derived from tuberculous cows was of very rare occurrence ; also, special preven- tive measures in this direction were not necessary. Koch's views, however, were only upheld by a few authorities, and the great majority of observers in the present day beheve in the unity of human and bovine tuberculosis. Nocard, Arloing, and others, beheved that, although there are three types of tubercle bacilh — ^viz., the human, the bovine, and the avian — they are in reality only modifications of the same organism produced by environment. In British veterinary literature of an early period the disease did not appear to attract much attention, if we are to judge from the articles on the subject and the cases recorded in the volumes of the Yeterinariof^. From 1828 to 1842 we find no mention of the disease, and in 1843 there occurs a translation of a paper read by M. Rayer before the Academy of Science on " The Comparative Frequency of Phthisis in Man and Animals." In this paper tubercular phthisis is stated to be, of all 108 SYSTEM OF VETEEINARY MEDICINE c chronic diseases, the most common both in man and animals ; and witl reference to the latter the points of distinction between " tuberculoui granulations," verminous and glanderous lesions, are given, attentioi being also directed to the disease in the dog. From this period to 1875 cases of the disease are occasionally reported, and it is surprising tc note that the majority of these are cases of equine tuberculosis ; but the clinical histories and the description of the pulmonary lesions given read remarkably hke those of glanders. In 1854 an article on " Tubercular Disease in Animals in India " appears. From the year 1875 onwards the disease attracted more attention, and in both the Veterinarian and Vderinary Journal numerous editorials, articles, and clinical records appeared. Amongst those who devoted much labour to the subject we may mention Fleming and Walley. Since the discovery of the tubercle bacillus the disease has received an enormous amount of attention from both veterinary pathologists and clinicians, and the literature on the subject is very extensive. The discovery of tuberculin by Koch in 1890 has proved of inestimable im- portance with reference to the diagnosis and prophylaxis of tuberculosis. Geographical Distribution.— The disease is found in most parts of the world, and its prevalence seems to be unaffected by cUmatic influences. It is said to be rarely met with in Iceland, Newfoundland, Arctic North America, the Gulf States, the northern parts of Norway, Sweden, Lapland, and Finland. Jersey cattle are stated to be free from the disease when in their native country, but when housed in infected British cowsheds they frequently become affected. In Japan the indigenous breeds of cattle are said to be unaffected, and the same is said of the Argentine native cattle ; but when the latter are crossed with English breeds, the offspring are subject to the disease, the explanation being that infection occurs from the imported parents, when tuberculous. Occurrence.— Tuberculosis may be justly described as the most wide- spread of diseases in animals, but it is unevenly distributed in the various species. Cattle are remarkably subject to the malady, and statistics show a very high percentage in dairy cows. In the Berlin dairies 75 per cent, were found to be affected, in London 26 per cent., in Edinburgh 20 per cent., and in Dublin about 12 to 15 per cent. Next to cattle, swine show the largest number of cases . The horse is not specially liable to the disease, but since 1888 a number of cases have been recorded, and it is probable that with more exact methods of diagnosis it will be found more common than was formerly TUBEECULOSIS 109 imagined. In sheep the disease is rarely met with, the percentage of affected animals being about 1 in 5,000. It can, however, be readily conveyed to them by experimental inoculation. Goats are very rarely the subjects of tuberculosis in Great Britain, but the fact that these animals only form a small part of the animal population, and are usually kept singly, must be taken into consideration. On the Continent, however, where goats are much more numerous, and the conditions under which they are kept favour the spread of infec- tion, caprine tuberculosis is more commonly met with. According to Ostertag, goats kept in stalls become tuberculous to the same extent as cattle. The dog and cat were formerly regarded as not being very susceptible to the disease under ordinary conditionsj but of late years, as more attention is being paid to the subject, and more exact methods of diagnosis adopted, the number of cases recorded has largely increased. In several instances infection from man to these animals has been traced. Birds are very susceptible to the disease,- and it is common in farm- yard poultry, in pheasants kept in aviaries, and in cage-birds kept in zoological gardens. According to Frohner, about 25 per cent, of parrots brought to the Berlin Veterinary School for treatment are tubercular. The disease has rarely been observed in wild animals in a state of nature, but it occurs when they are kept in confinement, as in zoological gardens. Monkeys are very susceptible, and reptiles and fishes may also be affected^ also guinea-pigs and rodents. With reference to the susceptibihty of the different species of animals to tuberculosis, McFadyean pointed out that it was fallacious to calculate this from the frequency with which the disease attacks the individuals of each species. Account should be taken of the fact that the exposure to risks of infectioh may not be uniform in all species. " There is every reason to suppose that the main cause of the excessive prevalence of tuberculosis in cattle is not their great natural susceptibility to infection, but their indoor existence, which multiplies the chanbes of infection. Conversely, the escape of sheep is not due to natural resistance to infection, but to the fact that their outdoor life minimises the risk of infection. Tuberculosis is a disease of animals that have to spend the whole, or a great part, of their existence in houses."* We may, however, remark that at the Tuberculosis Congress of 1901. Eeeves the Agent General of New Zealand, stated that tuberculosis was frequently detected in cattle that have never been housed. * Journal of Comparative Pathology and Therapeutics, vol. v. no SYSTEM OF VBTERINAEY MEDICINE ETIOLOGY. The essential cause of tuberculosis is the Bacillus tubercidosis, which, gaining an entrance to the tissues of the animal body, multiphes therein, and induces the characteristic lesions of the disease. Hereditary transmission at one time was regarded as an important etiological factor, but, owing to the researches of Bang, it is now clearly demonstrated that tuberculosis is not an hereditary disease. Hereditary predisposition, however, undoubtedly plays an important part in its genesis. According to Moussu, the offspring of tuberculous parents have not the same vital power to resist infection as those born of healthy parents, and a greater tendency exists in them to contract the disease. He regards this aptitude, or predisposition, as one of the essential factors in the development of the malady, as the tubercle bacilli exert their effect more readily under such conditions. BACTEEiOLoaY. — The tubercle bacillus is a thin rod-shaped organism, its average length being from 2 to 4 /x, and its breadth about | to | /i. Occasionally bacilli twice this length may be found. They may be straight, but are often slightly bent or curved ; they have rounded ends, and are aerobic and non-motile. The longer rods may not stain uniformly, and thus may show alternating stained and unstained portions, a beaded surface composed of a series of round or oval granules being produced. The unstained portions, oval in shape, are sometimes regarded as spores, but it is doubtful whether this view is correct. The bacilli may be solitary, but both in the lesions and in artificial cultures they tend to group themselves together in a manner resembling bundles of faggots. In the tubercles they are often found to arrange themselves in a radiate manner at the periphery of the giant cells. Variations. — Small branching forms may be found, and complex struc- tures forming club-shaped groups resembling actinomyces are described. Habit. — The tubercle bacillus is regarded by most authorities as a strictly obligatory parasite that cannot multiply as a saprophyte in temperate climates, as its growth is slow even at temperatures slightly below that of the body. Some investigators, however, including Nocard, have shown that the bacillus of avian tuberculosis can be made to live in suitable dead mixtures of organic matter. The bulk of evidence goes to show that the bacillus does not grow free in Nature, and that it occurs only when it is deposited with tuberculous discharges from the body. Staining Reactions. — There are two important peculiarities in con- nection with the staining reactions of the tubercle bacillus ; (a) It offers TUBERCULOSIS 111 marked resistance to staining with the ordinary basic aniline dyes. This is believed to be due to the presence of fatty or waxy substances in the outer part of the bacillus. (6) It retains the stain after treatment with aqueous solutions of minerail acids, and hence is termed " acid-fast." Other pathogenic bacilli are now known to be acid-fast — viz., the bacillus of Johne's disease and the bacillus of leprosy ; the latter disease, however, does not occur in animals. Other bacterial species also share this characteristic — ^viz., the Bacillm smegmatis, the Timothy grass {Phleum pratense) bacillus, the dung bacillus of Moeller and the butter bacillus of Rabinowitsch. Occurrence in the Body. — The tubercle bacillus is a tissue parasite, and, although it may be carried by the blood-stream, there is no direct evidence to show that it ever multiplies therein ; moreover, the bacilli > are never found in large numbers in the blood. In post-mortem examina- tions the bacilli are found almost entirely confined to the lesions. In tuberculous poultry they are said to occur in the liver without any lesions being observed in this organ. The bacilli occur in large numbers in actively growing tubercles, but are scanty in the chronic processes of lymph glands and of joints. If a tuberculous focus communicates with a vein or with lymphatic vessels, the bacilli may be spread throughout the body. According to von Behring, Calmette, and Gudrin, the bacilli may be located in the tissues, especially the glandular — e.g., the mesenteric glands — without any macroscopic lesions being observed. In old lesions their presence may not be detected microscopically, and cultures and inoculations may be necessary to demonstrate the true nature of the specimens. Resistance and Vitality. — Tubercle bacilli possess a moderately strong resistance to high temperatures. According to Bang, a temperature of 85° C. was sufficient to render them harmless. Jensen demonstrated that when the bacilli were uniformly distributed, exposure for ten minutes to a temperature of 75° C. killed them. The higher the temperature, the shorter is the period of exposure necessary to render them innocuous. Exposure to sunlight is said to destroy them in from two to four hours, but some observers state that several hours' exposure is necessary for this purpose.. As regards the effect of chemical agents on the bacilli, solutions of tV to J^ per cent, of perchloride of mercury render human tubercular sputum sterile in from twenty to twenty-four hours. In bouillon culture the bacilli are killed in thirty seconds by a 5 per cent, solution of carbolic acid, by a 1 per cent, solution of the same acid in one minute, and by a 1 to 1,000 per cent, solution of perchloride of mercury in ten minutes. 112 SYSTEM OF VETERINAEY MEDICINE According to Cadeac, the bacilli remain virulent in ordinary water for 120 days. Human tubercular sputum, when dried, is said to remaiji;^ virulent for a year. Exposure to alcohol, putrefaction, desiccation, or freezing as low as — 8° C, is said not to render it sterile. Of 118 dust samples from hospital wards or the rooms of human phthisical patients, forty were infective and produced tuberculosis by inoculation into susceptible animals'; virulent bacilli were obtained from the dust of the walls of fifteen out of twenty-one medical wards ; but in two wards with many phthisical patients the results were negative, indicating that the dust in such regions is not necessarily infective (Osier). According to Moussu, contagion only occurs in cattle-byres as the result of the presence of animals with open tuberculous lesions, such as caverns in the lung, tuberculous bronchitis with ulceration of the mucous membrane, tubercular enteritis, etc. The bacilli are expelled in the saUva, nasal discharge, faeces, urine, etc., and contaminate forage, Htter,. manure, drinking-water, etc. After desiccation, the bacilli may be spread by currents of air. Mangers, hay-racks, drinking utensils, etc., may also become contaminated. According to Forster, when salt was sprinkled on pure cultures of the bacilli, they retained their vitality for two months. Portions of tubercular organs, finely minced and laid in salt brine for eighteen days ' still remained virulent. Tubercle bacilh may remain for six hours in gastric juice without their virulency becoming impaired, and twenty-four hours' exposure is necessary in order to destroy them. According to the feeding experiments of Cadeac, conducted on guinea- pigs, alimentary tuberculosis was not produced with certainty except the animals received at least 1 gramme of tubercular material moderately rich in bacilh. In smaller amounts the results were uncertain, varying, and Umited. Wesner's experiments showed similar results (Ostertag). Types o£ Tubercle Bacilli.— For descriptive purposes, three types of tubercle bacilh were distinguished by the Royal Commission on Tuber- ■ culosis in the final report (1911)— viz., the bovine, the human, and the avian type— and from this report the following notes and extracts are taken : The Bovine Type.— In natural cases of tuberculosis in cattle, this is said to be the only type of bacillus present. It is distinguished by its cultural characters and by the characteristic effects produced when it is inoculated in certain doses into calves and rabbits ; also it grows solely on serum. In arriving at a conclusion as to the type of the bacillus, these features must be taken into consideration. The bovine type of TUBEECULOSIS 113 tubercle bacillus has been, termed " dysgonic," because of its slow growth on serum. At the end of two or three weeks it forms a thin, greyish, uniform growth, which is neither wrinkled nor pigmented. These properties, as we shall see, are in contrast with those shown by the human type of tubercle bacillus. When 50 milligrammes of a culture of bovine tubercle bacilh are administered to a calf by subcutaneous injection under the skin of the neck, severe generahsed tuberculosis results, which starts from the point of inoculation, and death generally ensues within eight weeks. This marked virulence is in contrast with the effects produced by the other types of tubercle bacilli. In rabbits, O'Ol or 0-1 milUgramme of a culture of bovine tubercle bacilli administered by intravenous injection produced generahsed tuberculosis, terminating in death within five weeks ; with doses of O'l to 1 milligramme given by intraperitoneal injection, extensive tuberculosis of the peritoneum and abdominal lymphatic glands, ex- tending afterwards to the internal organs, was produced ; while sub- cutaneous inoculation with doses of 1 milhgramme to 10 milUgrammes caused a local lesion, with tuberculosis of the neighbouring lymphatic glands, also of the lymphatic glands of the body and of the internal organs, especially the lungs and kidneys. Death occurred in from 29 to 165 days and 28 to 101 days, according to the doses employed. In the goat, pig, and cat, subcutaneous inoculation of the bovine tubercle bacillus produces generalised tuberculosis, and, provided the dose be adequate, the results are of equal importance in distinguishing this bacillus from the other types, as those obtained by inoculating the calf and rabbit. In the chimpanzee, monkey, and guinea-pig, very small doses of the bovine tubercle bacillus administered by subcutaneous inoculation produce acute tuberculosis. The dog shows marked resistance to subcutaneous inoculation of the bovine tubercle bacillus, but large doses inoculated intravenously or intraperitoneally may cause general tuberculosis and deathf The rat and mouse also prove highly resistant to the subcutaneous inoculation of the bovine tubercle bacillus ; but if administered by intra- peritoneal inoculation, the bacillus tends to multiply in the body, and can be demonstrated in large numbers in the organs, and even in the blood ; but no tuberculous lesions are formed, such as occur in animals susceptible to this type of bacillus. In the horse moderate doses of the bovine tubercle bacillus, adminis- tered bv subcutaneous inoculation or by feeding experiments, do not 8 114 SYSTEM OF VETERINARY MEDICINE produce progressive tuberculosis ; if, however, a dose of 10 railligrammes be given intravenously, death from acute tuberculosis occurs in twenty days. In the fowl even large doses of bovine tubercle bacilli, administered by intraperitoneal or intramuscular injection, produce only a local lesion. If, however, the bacillus be administered by intravenous injection, death occurs in about half the number of cases, being usually preceded by emaciation, the post-mortem generally showing pulmonary oedema and pallor of the liver, while in some instances definite tubercles are found in the lungs, and necrotic areas in the liver. It was found that dead tubercle bacilli of the bovine type injected intravenously produced similar effects to those of the live bacilli ; hence the fatal results were beheved to be due to the toxic efiect of these micro-organisms. The Human Type. — This is the type of bacillus found in the majority of cases of human tuberculosis. In consequence of its more rapid growth on serum as compared with that of the bovine tubercle bacillus, it is described as " eugonic." The growth tends to assume a wrinkled appear- ance on glycerinated media, and becomes more or less pigmented on all media. In calves it was found that a subcutaneous inoculation of 50 milli- grammes of a culture of the human bacillus under three weeks old did not produce progressive tuberculosis or cause death. In most cases a local lesion resulted, consisting of a mass which was either large or small, and might become converted into a cyst surrounded by a fibrous capsule. When internal lesions resulted, they generally consisted of caseous or calcareous nodules in the lymphatic glands nearest the seat of inocula- tion, or of a few calcareous tubercles in various internal organs. The results of the experiments carried out were, that in about half the number the lesions did not extend beyond the glands nearest to the seat of in- oculation, and the conclusion drawn was that the human tubercle bacillus possesses a much lower virulence for the calf than the bovine tubercle bacillus. In the rabbit subcutaneous inoculation of the human bacillus gave, as a rule, similar results to the above. When, however, intravenous inoculations are carried out in this animal, a slowly progressive tuber- culosis with hmited lesions is induced in the majority of cases, which is in marked contrast with the acute generalised form of the disease, ter- minating in death .within five weeks, which occurs when similar doses of the bovine type of bacilli are employed. In some cases, however, the rabbit shows extensive and fatal tuberculosis from inoculation with the human type'of bacillus. TUBERCULOSIS 115 In the goat and pig inoculation with the human bacillus was found to produce only a slight retrogressive tuberculosis, but pigs were shghtly more susceptible than calves. In the chimpanzee, monkey, and guinea-pig, inoculation with the human tubercle bacillus produced acute tuberculosis, the eiSect in the two former animals being similar to that following inoculation with similar doses of the bovine bacillus ; but in the guinea-pig the dm-ation of life was longer when the human bacillus was employed. In the dog the effects are similar to those produced by the bovine type of bacillus. In the cat resistance is shown to the human tubercle bacillus when administered by all methods, including feeding experiments. Intra- peritoneal inoculation produced a few tuberculous lesions which were not widely distributed, and did not affect the health of the animal. In the rat and mouse intraperitoneal injections of large doses of human tubercle bacilli resulted in dissemination of the bacilli over the body, and their multiplication in the tissues ; but death occurred without the production of characteristic tuberculous lesions. In the fowl the effects produced were similar to those induced by the bovine tubercle bacillus. In the horse one experiment was carried out, and a subcutaneous injection of 50 milligrammes of the human bacillus produced only a local lesion. It is of interest to note that in the case of a gnu and of an antelope that suffered from generalised tuberculosis, naturally acquired, the human type of tubercle bacillus was found in the lesions ; and in the case of a monkey and a chimpanzee, under similar conditions, the pres- ence of the human bacillus was also demonstrated. In a case of naturally acquired tuberculosis in a cat, a culture isolated directly from an affected mesenteric gland grew like the bovine tubercle bacillus, and, like the latter, it produced fatal generalised tuberculosis in rabbits. " These cases show that the tuberculosis developed by mammals kept in a state of captivity may be due either to the human tubercle bacillus or to the bovine type. Owing to the small number of cases investigated, no conclusions can be drawn as to the relative frequency of infection of such animals by the one or the other type of bacillus." Another point of interest is with reference to the transmutation of the bovine bacillus into the human bacillus, and vice versa. Although most of the attem;^ts in this direction failed, and a few only were equivocal, the Commissioners stated: "Thus we are inclined to regard transmutation of bacillary type as exceedingly difficult, if not 116 SYSTEM OF VETERINAEY MEDICINE impracticable, of accomplisliment by laboratory procedure, though, in view of certain instances in "which we obtained from one and the same human body both types of bacillus, we are not prepared to deny that the transmutation of one type into another may occur in Nature." Certain bacilU which were isolated from cases of lupus in man and tuberculosis in the horse possessed exceptional characters. " In some of these cases the bacilli had the ordinary cultural characters of the .bovine type, associated with a degree of virulence for the calf and rabbit no greater than is usually exhibited by the human type." These might be regarded as distinct fixed types, or as either modified human or modified bovine bacilli. " On the former assumption they had acquired the character of growth ordinarily exhibited by the bovine type, and on the latter assumpT tion they had lost the higher degree of virulence for certain animals which is characteristic of the bovine type. The latter appears to be the more probable explanation, and if that view be accepted, the discovery of these exceptional bacilU makes it impossible to regard difference of virulence for the calf and rabbit as suflS.cient to establish the non-identity of the human and the bovine types." " There would, therefore, remain only slight cultural differences on which to found the conclusion that the human and the bovine types represent two distinct organisms. We prefer to regard these two types as varieties of the same bacillus, and the lesions which they produce, whether in man or in other mammals, as manifestations of the same disease." The Avian Type is the one present in cases of natural tuberculosis occurring in poultry, and shows certain peculiarities with reference to its growth ; thus it forms a slimy, whitish growth which is readily emulsi- fied, and it grows especially well on glycerinated media. The fowl is very susceptible to the avian bacillus by intravenous, subcutaneous, and intramuscular inoculation, also when feeding experi- ments are carried out. The lesions produced by inoculation occur in the spleen and hver, and frequently in the lungs, cervical glands, muscles, and bones. Similar effects are produced by feeding experiments, but in addition lesions of the intestinal mucosa are observed. In the parrot similar lesions are produced, but when feeding ex- periments are carried out, intestinal lesions are not so constantly observed as in the fowl. The parrot is susceptible to the action of both the bovine and human tubercle bacillus, and when either of these is administered by inoculation or by feeding, the lesions are similar to those produced by the avian bacillus. TUBERCULOSIS 117 It is found that the bovine bacillus is apparently more virulent for the parrot than either the human or the avian bacillus. In the rabbit and mouse the avian bacillus causes progressive tuber- culosis, these being the only two mammals in which this form of the disease is produced. The rabbit shows certain pecuUarities in the results produced by the avian type of tubercle bacillus. When moderately large doses are given by inoculation, they prove fatal, but the results show that the avian type of bacillus is less virulent for this animal than the bovine type, but more virulent than the human type. Subcutaneous inoculation of the avian^ bacillus in doses ranging from 50 miUigrammes to a fraction of a milhgramme produce in the rabbit a very chronic form of tuberculosis, in which the distribution of the lesions differs to a marked extent from that caused by the bovine and human tubercle bacillus, and this peculiarity is practically unaffected by the size of the dose administered. Similar results follow intravenous injection of a very small dose (0-001 milligramme). In addition to local lesions, the nearest lymphatic glands are involved, and also the kidneys to a variable extent. Slight oedema of the lungs, with a few tubercles on the surface of these organs, is observed, also caseating tubercles in the areolar tissues, in a few of the lymphatic glands, and in the testes ; while the liver and spleen are but rarely affected. The most characteristic ' and important lesion, however, is a chronic tuberculosis of the joints of the limbs. Tuberculosis of the joints occa- sionally occurs after intravenous inoculation with the human tubercle bacillus, but not after subcutaneous inoculation, and similar lesions may be observed after subcutaneous inoculation with the bovine bacillus, provided the animal survives for a sufficiently long period. In the mouse the avian bacillus produces generalised tuberculosis,, whether administered by subcutaneous or intraperitoneal inoculation, or by feeding. In the calf, pig, horse, cat, rat, monkey, and guinea-pig, progressive tuberculosis is never produced by the avian bacillus, although in some instances it may multiply in the body and become disseminated in the tissues; but if a large dose be administered by intravenous mjection a fatal result may ensue. In the dog the intravenous injection of large doses produces no effects. In one experiment carried out on a chimpanzee, 50 milUgrammes injected subcutaneously produced no effect, and on post-mortem examina- tion of the animal three years afterwards no tuberculous lesions were discovered. 118 SYSTEM OF VETERINARF MEDICINE MODES OP INFECTION. 1. Heeeditaey Teansmission.— Congenital tuberculosis is very rarely met with. According to Moussu, the passage of tubercle bacilli through the placenta only occurs under exceptional conditions, such as when the bloodvessels are affected. Other authorities hold that the " almost constant method of trans- inission in congenital tuberculosis is through the blood-current, the bacilli penetrating by way of the placenta. Certain authors hold that in these cases the placenta is invariably the seat of tuberculosis, and tubercles, indeed, have been demonstrated in several cases ; but there are undoubted instances in which, with an apparently sound placenta, both the placental blood and the foetal organs contained tubercle bacilli, notwithstanding the fact that the organs also appeared normal."* Tuberculous lesions of the maternal genital organs may lead to congenital infection of the foetus. Moussu points out, however, that tubercular disease of the ovaries, Fallopian tubes, or uterus, generall:|r prevents pregnancy and causes steriUty. Direct paternal infection, according to the same author, is only possible when ulcerating tubercular lesions of the testicle, prostate gland, or vesiculse seminales, are present, and it is very rare. The experimental work of Gartner and others shows that healthy female rabbits impregnated by tuberculous males do not produce tuber- culous offspring, although, the females may contract the disease. The consensus of opinion in the present day is that infection usually takes place after birth, and that the disease is rarely present in the newly-born, even when both parents are tuberculous. The proportion of tuberculous cows that produce calves congenitally affected is said by some observers to be about 1 in 300, but this estimate seems far too high. According to McFadyean, congenital tuberculosis in the calf is very rare ; he recorded the first case in Great Britain in 1891. Up to 1891 only six cases were recorded on the Continent, in which the presence of the disease was proved by the demonstration of the tubercle bacillus. The proportion of cases in calves under one month old is said to be about 1 in 70,000. 2. Infection by Inhalation. — This is recognised by some authorities as the most probable mode of infection in cattle. As compared .with the mode of infection by ingestion, it may be described as the older theory. It is beUeved to take place in confined, Ul-ventilated buildings, the chief source of the infection being the expectorate coughed up by a * Osier's " Principles and Practice of Medicine." TUBEECULOSIS 119 tuberculouli animal. This infective material may be in tlie form of a fine spray, which contaminates the surrounding atmosphere, and, being inhaled by the other occupants, may be the means of introducing the bacilli into their lungs. Or the expectorate may be of a coarser nature, and, falling on surrounding surfaces or objects, it becomes desiccated ; it is readily disturbed, and, in the form of dust particles, contaminates the atmosphere, and may thus prove a source of infection by inhalation. Direct "infection of the lungs may be produced by the above means. This view is contested by many authorities, who hold that infection by ingestion is by far the more common method. Lately McFadyean has stated that primary tuberculosis of the lungs is probably always caused by inhalation of infective material, and that when the lungs are affected from the alimentary tract, the pulmonary lesions are secondary to diseased conditions elsewhere in connection with the digestive system. In a paper entitled " What is the Common Method of Infection in Tuberculosis V* he weighs the evidence for and against the inhalation theory of infection in a remarkably clear and lucid manner, and arrives at the following conclusions : " (1) The inhalation of tubercle bacilli suspended in the atmosphere is a very certain method of infection in susceptible animals, even when small doses of bacilli are employed. " (2) Experimental infection with tubercle bacilli by way of the alimen- tary canal is comparatively difficult to realise even in highly susceptible animals, and success is certain only when very large doses of bacilli are administered. " (3) With few exceptions, in animals experimentally infected with tuberculosis by way of the intestine, the primary lesions are intra- abdominal, and the intrathoracic lesions, when present, are secondary. " (4) Inhalation is probably the comnaonest natural method of infection in those species (man and cattle) in which the primary lesions of tuber- culosis are usually intrathoracic. " (5) Naturally contracted cases of tuberculosis in man and other mammals can be ascribed to infection by ingestion only when the lesions, revealed at the post-mortem examination are confined to the abdomen, or when the existing abdominal lesions are recognisably older than those present elsewhere in the body." 3. Infection by Ingestion.— Chauveau (1868), Gerlach (1869), and others, held, as the result of their experiments, that infection by ingestion was the commonest method. Calmette, Guerin, and Whitla advanced a * Jmirml of Comparative Pathology and Therapeutics, September and December, 1910. 120 SYSTEM OF VETERINARY MEDICINE similar view, and claimed that ingestion of tubercular material can produce pulmonary lesions without causing any visible lesions in the intestinal mucous membrane. They found that in young animals the bacilli induced lesions in the mesenteric glands, but in older animals the bacilli more generally entered the lymph stream, and, reaching the pulmonary artery, passed to the lungs. These observers also held that the bronchial and mediastinal lymphatic glands may become infected as the result of ingestion of tubercular material without any lesions being found in the intestinal mucosa or iii the mesenteric glands. Further information on this subject, and an analysis of the views of various observers, will be found in the paper by McFadyean abeady referred to. Infection by ingestion may occur from feeding on fodder, etc., con- taminated by tubercle bacilli. When a number of cattle are fed together, a tubercular subject amongst these may contaminate the fodder during the act of coughing by depositing thereon the infective expectorate. Straw, litter, etc., may be contaminated by the faeces of animals sufiering from intestinal lesions, and so become infective if eaten by cattle or horses ; also, as tuberculous animals swallow a large proportion of the expectorate that is coughed up in the pharynx, the faeces may be rendered infective by this means. The pharynx and pharyngeal glands may become in- fected during the swallowing of food containing tubercle bacilli ; some observers, however, believe that this region is a seat of predilection for the disease, and that the bacilli are conveyed thereto by the blood. Dogs and cats may become infected by consuming food contaminated with expectorate from tuberculous human beings, or from ingesting meat or milk containing tubercle bacilli. Pigs are infected in a similar manner; probably tonsillar infection may occur in this species as in man. Birds contract the disease from the ingestion of grain, etc., contaminated with the faeces of birds suffering from tuberculosis, or by the sputum of infected human beings. It is probable that ingestion plays a very prominent part in the etiology of the disease in young .animals when these are fed on milk obtained from animals suffering from tuberculosis of the udder. Foals fed on such milk may become infected ; also calves, pigs, and probably dogs. According to Friedberger and Frohner, the milk of tuberculous cows may contain tubercle bacilli in the absence of mammary tuberculosis. Whey, cheese, and, butter prepared from the milk of tuberculous cows, nay transmit the disease even after a lapse of from one to four weeks, according to the investigation of Bang, Roth, and others. Bang has also demonstrated by inoculation experiments that skimmed milk TUBERCULOSIS 121 ^d cream prepared hj centrifugal methods from tubercular milk are infective. 4. By Inoculation. — This mode of infection is rare in animals. It may occur if tubercle bacilli become implanted deeper than the epidermis, local tubercle of the skin' resulting. The lesion occurs in the form of raw warty projections, which contain tubercle bacilli and show caseating centres at certain points. A similar form of the disease may occur in man as the result of local infection from handling organs or parts afEected with tuberculosis when abrasions are present on the skin of the hands, most of the cases recorded being in demonstrators of pathology, butchers, handlers of hides, etp. The dorsal surfaces of the hands or fingers are usually affected in the form of a reddened mass of granulation tissue known as the Verruca necrogenica of "Wilks. It usually remains local, but a case is recorded in which, after excision of the primary lesion, the lymph glands of the axilla became infected, and, when removed, showed tubercular changes and the presence of tubercle bacilli. It is said that some cases of mammary tuberculosis in cows may be due to local infection through a wound or abrasion of the skin of the udder. According to Bang, it is possible that primary tuberculosis of the udder may occur by tubercle bacilli penetrating through the canal of the teat. Tuberculosis can be readily transmitted to animals by experimental inoculation, a fact which is extensively taken advantage of in testing milk or other material suspected of being infected by the disease. Usually two forms of inoculation are made use of — ^viz., the subcutaneous and the intraperitoneal. If the suspected material contains living tubercle bacilli, tuberculosis results, at first as a localised infection, which usually tends to become generalised afterwards, and to prove fatal. Rare Modes op Infection. — ^Amongst these may be mentioned tuberculosis of the vagina in the cow, due to transference of bacilli by the penis of a bull that has recently served a cow suffering from this disease in the vagina. On the other hand, the bull may contract tuberculosis of the penis from a similar source, and convey the disease to the vagina of a healthy cow by coition. Latent Infection. — Some authorities, including von Behring and Baumgarten, are of opinion that it is possible for tubercle bacilU to remain latent in the tissues of young animals, and to subsequently develop in adult life, and give rise to the disease. The reasons for this phenomenon are not understood, and this form of infection cannot at present be regarded as otherwise than a theoretical one. 122 SYSTEM OF VETBEINARY MEDICINE Conditions influencing Infection. — Dark, damp, ill-ventilated, badly-drained buildings, favour infection. The bacilli are less likely to be inhibited or destroyed under such conditions. Overcrowding offers facilities for the conveyance of the disease from the affected to the healthy animals. According to Friedberger and Frohner, the vitality of the respiratory organs becomes weakened in cattle kept in ill- ventilated sheds; hence they are predisposed to the entrance and development of the tubercle bacilli in their systems. The same authors state that catarrhal affections of the respiratory mucous membrane, which are often caused or favoured by the air in ill- ventilated sheds, favour the penetration of the bacilli; also that the abundant production of milk and the strain of yearly breeding tend to weaken the system and impair the natural powers of resistance to infection. Continuous inbreeding is regarded by the same authors as a predisposing factor. With regard to age, the disease is most prevalent in old milch cows, especially those kept in town dairies. Infection in cattle is usually the result of cohabitation with affected animals. Contact between diseased and healthy animals for a period of some days, or even weeks, does not seem sufficient to transmit the disease. Nocard regards a mean period of five to six months as necessary, aid Moussu has arrived at a similar conclusion as the result of observa- tions made by placing tuberculous cattle and healthy cattle together in bjrres reserved for such researches. Of course, the differences in in- dividual susceptibility must be taken into consideration when dealing with such experiments. MORBID ANATOMY. The Tubercle is the primary lesion produced by the Bacillus tvber- Nodules, identical in structure to tubercles, are found in other diseases, and in the present day the term " nodule " is applied to lesions which are not tuberculous, while the term " tubercle " is restricted to the primary lesion caused by the tubercle bacillus. The tubercle is very small at the commencement of its growth, and increases to the size of a pin's head or larger. A number of these small tubercles may coalesce and form masses of various sizes. The essential cause of the formation of these tubercles in any organ or tissue is the presence of tubercle bacilli, which multiply and cause irritation. The effect of this irritation is to cause first a proliferation of the fixed cells and the production of epithelioid and giant cells. An TUBERCULOSIS 123 inflammatory reaction next occurs, associated with exudation of leucocytes. According to Baumgarten, three varieties of cells are found in a typical fully-formed tubercle. 1. EfitheUoid OeZk— These are the first cells formed, and their origin is believed to be the proliferation of the fiixed cells of the part, especially those of connective tissue, endothelium of the blood and lymphcapillaries, and sometimes from epithelial cells. The epithelioid cells are the most numerous, and very young tubercles are formed altogether of them. In shape they are generally angular ; they present a single vesicular nucleus and a large cell-body, and some may contain tubercle bacilli. 2. Round Cells. — These are leucocytes which have migrated from the capillaries of the infected focus. In the fully-developed tubercle they are not numerous, and are found chiefly at its periphery, and during the development of the tubercle many of these cells undergo rapid destruc- tion ; they are polynucleaT, but as growth proceeds in the lesion, they become chiefly mononuplear, and do not undergo marked degeneration. 3. Giant Cells. — These are large" in size and multi-nucleated. They are probably formed by fusion of the epithelioid cells around tubercle bacilli. According to certain observers, in some, but not all, tubercles giant cells are formed by an increase in the protoplasm and in the nuclei of an individual cell, or possibly by fusion of several cells. As compared with the other cells in a tubercle, they are in a minority. In man the giant cells seem to be in inverse ratio to the number and virulence of the bacilli (Osier). In developed tubercles, giant cells are constantly present in the ox and horse ; in the latter they generally occur in considerable numbers. They are usually present in tubercles of swine, and are often found in those of the dog and cat. In the horse the bacilli in a group often occupy the body of the ceU, whil^ in the ox and other animals they are often radially arranged towards the periphery of the cell between the nuclei. According to Ostertag, the formation of giant cells only fails to occur in cases of extensive penetration of tubercle bacilli, or when the latter are very virulent. In some instances no bacilli are present in the giant cells. Giant cells are not peculiar to tuberculous lesions, but their presence is of diagnostic value, especially when they are found in lesions showing evidences of necrosis and caseation. They bear a close resemblance in shape to the giant cells of bone-marrow, and, also in common with the latter, the multiple nuclei are generally massed together towards the periphery of the cell. As regards situation, giant cells are found scattered 124 SYSTEM OF VETERINARY MEDICINE in an irregular manner throughout the tubercle. The presence of these cells in a tubercle is, according to McFadyean, an indication that it has been forming for at leaBt two or three weeks. Some authorities regard giant cells as a special variety of phagocytes. In addition to the structures mentioned, there is also found in a tubercle a reticulum of fibres formed by the fibrillation and rarefaction of the connective-tissue matrix, usually most apparent at the margin of the growth. A tubercle is usually composed of the three varieties of cells mentioned above and tubercle bacilli, while in some instances traces of the original histological structure of the part can be recognised. Generally these disappear, together with the capillaries, and, as no new vessels are formed, the tubercle is non-vascular. Exceptions to this rule as regards vascu- larity are met with in the tuberculous lesions of the pleurae and peri- toneum of the ox, as the tubtoles in these locations contain blood- vessels. Degenerative Changes in the Tabercle — 1. Caseation. — After four weeks, or sooner, a process of coagulation necrosis occurs in the cells at the central part of the tubercle. These lose their outline, become irregular, no longer take the usual stains, and finally are converted into a homo- geneous substance devoid of structure. Caseation quickly follows on necrosis, the process extending from the centre outwards. Prior to the occurrence of degenerative changes, the tubercle is grey in colour and somewhat translucent in appearance ; after necrosis occurs, the centre becomes opaque, and with the advent of caseation it becomes of a yellow colour, and the tubercle is gradually converted into a yellowish-grey body, in which tubercle bacilli are still present, but bloodvessels are absent. These changes are due to the direct action of the bacilli or of their products. According to Kitt, caseation is to be ascribed to a toxic material which is given off by the bacilli. Caseation is constant in tubercular lesions of the ox, horse, pig, and fowl, but there is less tendency to this change in those of the dog and cat. Although caseation is pathognomonic of tubercle, it is not peculiar to this disease, as this degenerative change is also met with in the pul- monary lesions of glanders and in other specific inflammations. 2. Calcification. — ^In this, a deposition of irregular granules of car- bonate and phosphate of lime occurs in the caseous part of the tubercle. This change is most marked in the ox and pig, and occurs with compara- tive frequency in the horse, while it is uncommon in the dog and cat. The tubercle is hard and cretaceous both in appearance and on palpa- TUBERCULOSIS 125 tion, and grates under the knife. Calcification is regarded as evidence of chronicity in tubercular lesions. 3. Softening. — ^In the ox the caseous material in the tubercle may- become converted into a yellow custard-like material, while in the horse it resembles thick pus. 4. Fibroid Degeneration. — This is also known && fibrosis and sclerosis. According to McFadyean, it is a very uncommon alteration in the tuber- culous lesions of animals. In the tissue of the tubercle a productive fibroid inflammation occurs, which may convert the lesion into a firm, hard structure. Or the change may be of a fibro-caseous nature, the tubercle showing a caseous centre, while the zone nearest to the normal tissue shows fibroid development. Th-e process is regarded as a con- servative and healing one. When present, it is chiefly found affecting the lesions in the peritoneum, and very few bacilli can be discovered in them. R61e played by Tubercle Bacilli.— When the bacilli gain access to the tissues, provided they flnd a suitable soil, they multiply and form toxic substances or toxins, which exert an injurious influence on the tissue cells. The presence of the bacilli and of their toxins causes a reaction on the part of the tissues, as the result of which the tuberculous lesion is formed. If the soil is not suitable, and the animal not very susceptible, or if the bacilli are not very virulent, the latter may remain enclosed in the primary lesion, or they may perish therein, and the animal recovers completely. More commonly, however, when the soil is suitable, the lesion becomes developed, and the effect produced is that the course of the invasion is delayed. The site of formation of the tubercle is in the connective tissue of the affected part, or in the walls of the bloodvessels and in the lymphatics of the part. Secondary Inflammatory Processes. — Extensive inflammation may be produced by the irritation resulting from the presence of the bacilli and their toxins. Thus in the lungs pneumonia may occur, with prolifera- tion of the connective-tissue elements in the septa, infiltration of the latter with round cells, and alterations in the bloodvessels and lymph vessels. Or the development and spread of the tubercles may be limited by the production of a cicatricial connective tissue, resulting from inflam- mation of a slow reactive type. Suppuration. — This process may occur in the tuberculous lesions of various organs, and also in the form of the so-called cold tuberculous abscess. In the latter the pus is described as " sterile " — i.e., it does not contain 126 SYSTEM OF VETEEINARY MEDICINE the usual pus organisms — and some authorities state that the material in the abscess is not histologically pus, but consists of broken-down cells and cheesy material. Such pus, however, is not sterile in the strict sense of the word, as it contains tubercle bacilli, which may be detected by staining and microscopical examination, or, if not, by guinea-pig inocula- tions. In some instances the number of tubercle bacilli in such pus may be small, and may thus be overlooked by microscopical examination, or they may have died out. Such pus would be more correctly described as "sterile on ordinary media," as tubercle bacilli will not grow on these. Ordinary pus, however, occurs in tuberculous lesions of joints and bones, and is said to be due to the products of tubercle bacilli or to a mixed infection. It may also occur in pulmonary tuberculous lesions, and is said to be largely the result of an infection with pus organisms. Anatomical Forms o! Tuberculosis. — These vary according to the predisposition of the tissues in different animals, and also according to the extent and duration of the disease. The principal forms met with are as follows : 1. The Miliary Tulercle. — The structure of this has already been described (see p. 123). It is the earUest manifestation of the tuberculous lesion. Miliary tubercles take about two weeks after infection has occurred to develop to macroscopic size, and after four weekte they become as large as ordinary pin-heads. The microscopic stages at the commence- ment may be observed in from five to ten days after infection. In colour these tubercles are of a grey or yellowish-red ; they may be single or multiple, and may extend widely over a large surface or become disseminated through the tissues of the organs affected, the pleurae and lungs beiug most commonly involved. Acute MUiary Tuberculosis. — ^In this condition the organ affected is the seat of miliary tubercles which are of uniform size and age. Chronic Miliary Tuberculosis is characterised by a local multiplica- tion of the tubercles ; they enlarge in size, and the larger forms arise from either fusion or conglomeration of the smaller tubercles. When these tubercular masses occur on serous surfaces, they form what is sometimes termed " pearl disease " or " grapes." , 2. Diffuse Form. — In this form no well-defined tubercles are present. It is found especially on serous surfaces in the form of a soft grey or greyish-red layer; new bloodvessels are formed in the process, the lesion has a granular appearance, caseation only occurs to a slight extent, and not until a considerable time has elapsed. This type, of lesion is believed to depend on the presence of large numbers of bacilli through- TUBEECULOSIS 127 out the tissue, instead of being in separate groups, such as occurs in the ordinary form of the disease. When occurring in serous membranes, the lesion may cause actual exudation on the surfaces of the afEected parts. 3. Tuberculous Fungoid Granuloma.— This form of tuberculous lesion is chiefly met with in the pleurae and peritoneum, and occasionally in the intestmal mucous membrane. It results from the formation and profuse growth of cellular tubercles on a free surface. A vascular connective- tissue growth develops simultaneously with the tubercles, the result being the production of tumour-like masses of various sizes. These, by encroaching on each other, may form excrescences of large size and weight, covering extensive surface areas. Degenerative changes occur, such a§ caseation and partial calcification. 4. Tuberculous Gheesy Infiltration, or Infiltrated Tubercle. — The lungs and lymph glands are the organs chiefly afEected by this form of tuberculous lesion. It results from the fusion of several small foci of infection ; the latter may not be visible to the naked eye. Microscopical examination of these small foci in the lungs shows that they are composed of scattered centres surrounded by areas in which the alveoli are filled with exudative products and proliferation of the alveolar epithelium. Caseation occurs, due to the action of the bacilli ; generally only small groups of lobules undergo this change, but occasionally an entire lobe, or the greater part of the lung, may be so afEected. Ultimately the afEected area is converted into a dense caseated mass of a yellowish-white or a deep yellow colour. When the lymph glands are afEected by tuberculous in- filtration, they may form very extensive masses. 5. Tuberculous Ulcers occur especially in the intestine, larynx, and bronchi. They result from the disintegration of parts which have undergone caseation, and also from purulent softening of tubercles on the mucous membrane. In the intestine the ulcers show crater-Uke surfaces. On the base and margins of the ulcers minute tubercles are found. These lesions are common in the dog and cat, and occur especially on the skin in these animals. 6. Tuberculous Cavities, or Vomicw, are met with in the lungs, when a large extent of the pulmonary tissue is destroyed and converted into caseous masses ; the latter undergo central softening, and may be coughed up by the animal, an irregular cavity resulting. Vomicae are not so frequently met with in animal tuberculosis as in the human form of the disease, the reason probably being that animals are not permitted to live sufficiently long for the formation of this lesion. We may remark that the anatomical forms of tuberculosis which we 128 SYSTEM OF VETI;EINAEY MEDICINE have mentioned may be combined in a variety of ways, and special modifications may occur depending on peculiarities of tbe tissues involved in the different animals. We shall again refer to these points when considering the morbid anatomy of the individual organs affected. Modes of Dissemination o£ Tubercle Bacilli in the Body. — A knowledge of this subject is essential in order to understand the maimer in which the generaUsed form of the disease occurs. The primary lesion is the process which arises immediately at the point of entrance of the infection and in the vicinity of this point, without the co-operation of the circula- tion. From this primary lesion bacilli usually escape, most frequently ^y the lymphatics at its periphery. These bacilh are probably carried by the lymph-stream to the nearest lymphatic gland ; here they are arrested, and produce a new lesion and focus of infection^ Bacilli from this new lesion may, after a time, escape, and, reaching the next lymphatic gland, become arrested. When bacilli have reached the last of the glands on the path of invasion, they may be carried into the thoracic duct or into the right lymphatic duct, and so gain entrance to the venous system and to the general circulation. In the blood-stream they usually become arrested in the capillaries of various organs, but chiefly in the lungs. Generalised tuberculosis occurs in this manner. It is evidenced by the development of a large number of miliary tubercles in the lungs, and a smaller number in the liver, spleen, and kidneys. An important point to remember is that generalisation only occurs in a minority of cases, also that the commonest method by which bacilli spread throughout the body is by way of the lymphatics. It may be regarded as a definite rule, with few exceptions, that when an organ is affected with tuberculosis, the neighbouring lymphatic glands become involved. There are other modes of dissemination of the tubercle bacilh in the system. For example, in the lungs the bacilh escaping from an existing focus into a bronchial tube may, by the act of coughing, reach a larger bronchial tube, and then, by aspiration, be drawn into another- ramification of the bronchi. Or the bacilli may reach the trachea, and be drawn back into the opposite lung. Again, the pleura may be infected from the pulmonary surface by the bacilh spreading therefrom during the respiratory movements. The peritoneum may become infected by extension of the disease from the intestines, during peristaltic movements of the latter. In the aUmen^- tary canal infection may take place by means of expectorate containing bacilli being swallowed. TUBEECULOSIS 129 Primary and Secondary Foci. — Primary Foci include the lesions which arise at the point of entrance of the bacilli from outside the body, and also those in the vicinity of the infected part, the bacilli being carried to the latter by means of the lymphatics, and not by the circulation. To primary foci belong all primary lesions in mucous membranes and tubercles in their vicinity, also affections of the corresponding lymph glands and foci in serous membranes arising by extension of the original lesion. ' Tubercle bacilli, according to some authorities, do not regularly produce tubercular lesions at their point of entrance into the body, as they are capable of passing through the epitheUum of mucous membranes and causing lesions first in the neighbouring lymph glands. The point of entrance of the bacilli into a tissue is said to usually occur in regions where lymphatic glands are more or less exposed, such as the pharynx and intestine, and the point of infection may escape being involved if the bacilU are carried onward in a rapid manner by the lymph, the lesions appearing at first in the lymph glands. According to some authorities, feeding experiments carried out in pigs with tuberculous material show that the primary lesions occur in the mesenteric lymph glands, while the intestinal mucous membrane may escape infection. Authorities who beKeve that the commonest mode of infection in tuberculosis is by ingestion attempt to substantiate this view by the results of feeding experiments, and state that in animals fed on tuber- culous material the lungs may become the seat of primary tuberculosis, the bacilli being carried thereto by means of the chyle vessels, thoracic duct, and circulation. McFadyean, however, has shown* that the conclusions of Calmette, Guerin, and Whitla are unsiipported by the experiments they themselves carried out, and has also quoted numbers of feeding experiments which have given directly opposite results to those of the authorities named, and demoilstrated that primary pulmonary tuberculosis can with certainty be determined by the inhalation of tubercle bacilli (see p. 119). Secondary Foci. — ^In these, infection occurs through the agency of the blood-stream. By some writers they are regarded as hsema* togenous embolic foci, and they are found in internal organs at points where arteries branch into capillaries in' the interstitial connective tissue. Tubercles of large size may result, or conglomerations of smaller * See Journal of Comparative Pathology and Therapeutics, September and December, 1910. vnT. T " 130 SYSTEM OF VETERINARY MEDICINE growths ; they are sometimes termed " embolic tubercles." In the lungs both primary and embolic tubercles may occur. Local and Generalised Tuberculosis. — Local Tuberculosis, in a broad sense, indicates that the extension or distribution of the disease takes place through the lymphatics, and that the general circulation is not concerned in the dissemination of the bacilli. In cattle, tuberculosis has a pronounced tendency to localisation ; this is attributed by some to a prompt filtering action of the lymphatic glands, and also to the fact that the tuberculous products in these animals are, as a rule, poor in bacilh. Generalised Tuberculosis. — In this form the general circulation is said by some authorities to become the carrier of the bacilli. Penetration of bacilli into the systemic circulation is said to occur by means of veins becoming affected by tubercular processes, or the bacilli from tuber- culous lymph glands may reach the venous system by way of the thoracic duct or right lymphatic duct, as already mentioned. According to Weigert, when large numbers of bacilli enter the blood, a tuberculous condition of the walls of a bloodvessel or of the thoracic duct is present, and accounts for this phenomenon, Two principal forms of generaUsed tuberculosis are recognised by some authorities : 1. A slight infection of the blood, leading to the formation of isolated tubercles in various organs. These small tubercles usually grow to a larger size, and caseous foci appear, the condition being one known as chronic generidised tuberculosis. 2. In this form there is an extensive infection, which leads to the occurrence of innumerable tubercles in the majority of organs. This gives rise to the condition known as acute miliary tuberculosis. McFadyean, however, points out, as the result of numerous experi- ments, that even when large numbers of tubercle bacilli are thrown into the blood-stream embolic tubercles of the lymphatic glands are not set up, and that it is hardly hkely in natural cases of the disease for much larger numbers of bacilli than those introduced experimentally to find their way into the blood-stream ; otherwise the resulting pulmonary tubercles would be so numerous as to cause death in a short time, and it would be impossible to explain the presence of macroscopic lesions in the lym- phatic glands. He points out also that in generalised tuberculosis the kidneys, liver, and spleen, or all of these, may be free from macroscopic lesions, although the lungs contain myriads of embolic tubercles visible to the naked eye. The macroscopic lesions in the organs mentioned, and also in the lymphatic glands, are generally due to lymphatic infection, TUBERCULOSIS 131 and give no evidences of generalisation by way of the blood-stream. In some parts of the body at least the tubercle bacilli can be readily carried by the lymphatic vessels in a centrifugal direction — i.e., in a direc- tion contrary to what is believed to be the normal flow of the lymph- stream. These remarks do not apply to the congenital form of the disease, as the circulation differs in the foetus from that of the adult. The evidence of generalisation is the presence of tubercles of approximately equal size scattered throughout the entire spongy lung tissue. If the lungs are removed from the carcass prior to inspection, reliable evidence of generalisation cannot be obtained.* The various organs do not show a uniform predisposition to become infected by the bacilli. Certain organs appear to offer favourable condi- tions for the growth of the bacilli, and are frequently infected ; others are seldom attacked. Thus the lungs, lymph glands, and general lymphatic tissues, are the favourite seats of the disease. The lungs are especially exposed to infection by the inhalation of tubercle bacilli, and in a secondary manner by bacilli entering the venous system from the thoracic duct, and becoming lodged in the pulmonary capillaries. The liver is liable to infection from the entrance of bacilli by way of the lymphatics, and also by the portal vein. According to Kitt, the voluntary muscles show the greatest degree of resistance to the disease, and it is generally only the intermuscular lymph glands that are affected. Sequence of Organs affected in Generalised Tuberculosis. — In general- ised tuberculosis in cattle a certain sequence of the various organs in- volved is observed. Thus the bronchial and mediastinal lymph glands, the lungs and liver, are generally those first involved, next the spleen and kidneys, followed by the prescapular and inguinal lymph glands, and the udder, bones and joints. In females, when the posterior region of the peritoneum is affected, . the uterus is