A text-book of the principles and practice of veterinary medicine

Preface

The need of an up-to-date, scientific text designed for student use has been long felt by teachers of the internal diseases of animals. The author has personally experienced this need as a teacher of veterinary students for over twenty years. The few books available on the subject are either obsolete or so filled with errors that they mislead rather than instruct. Some of the best of them are translations from the German and French. In too many instances the translators have been neither veterinarians nor teachers of veterinary medicine, and too few of them linguists. Furthermore, the books in this field have not been designed for undergraduate students; they are bulky, comprehensive works of reference of little pedagogic value; all of them have been superseded by newer editions in the original tongue.

Although this volume is designed primarily for the student, it will be found valuable to the practitioner, investigator or intelligent stockman who may have need of knowledge of the fundamental principles of the practice of veterinary medicine presented in concise, clear-cut and at the same time not too dogmatic form.

While the author has many to thank for assistance in preparing this volume, among his fellow teachers, investigators and practitioners, he is especially indebted to Professor D. H. Udall, of the New York State Veterinary College, Cornell University, who kindly read the manuscript and offered many valuable suggestions from his rich experience, practically all of which have been incorporated in the book. Messrs. Lea & Febiger are also thanked for their patience, courtesy and efficient service in making the edition mechanically good. D. S. W.

Columbus, Ohio, 1917.

CHAPTER I. Diseases of the Nose and Adjacent Sinuses

1. Rhinitis 17

Croupous 20

Diphtheritic 20

Follicular 21

2. Epistaxis 22

3. Infectious Rhinitis of Swine 23

4. Animal Parasites in the Nose and Sinuses of the Head

(CEstrus ovis) 24

5. Catarrh of the Maxillary and Frontal Sinuses ..... 26

6. Catarrh of the Guttural Pouches 27

7. Tympany of the Guttural Pouch 27

CHAPTER II. Diseases of the Larynx

1. Laryngitis 28

Croupous 30

Edematous 31

2. Paralysis of the Recurrent Nerve (Roaring) 32

3. Tumors in the Larynx 34 vi CONTENTS

CHAPTER III. Diseases of the Bronchi

1. Catarrhal Bronchitis . 35

2. Verminous, Bronchitis 38

CHAPTER IV. Diseases of the Ltjngs

1. Congestion of the Lungs 41

2. Pulmonary Edema 41

3. Bronchopulmonary Hemorrhage 43

4. Pulmonary Gangrene 44

5. Abscess of the Lung 45

6. Chronic Alveolar Emphysema 46

7. Acute Interstitial Pulmonary Emphysema 48

8. Pneumonia 49

Fibrinous 49

Foreign-body 57

Metastatic 58

Interstitial ■ _ 59

9. Tumors in the Lung 60

CHAPTER II. Diseases of the Heart

1. Nervous Palpitation of the Heart 73

2. Slow Heart Beat (Bradycardia) 74

3. Intermittent Heart Beat 74

4. Hypertrophy and Dilatation of the Heart 75

5. Myocarditis 76

6. Endocarditis 77

Acute . 77

Chronic 79

7. Rupture of the Heart 80

8. Aneurysm of the Aorta 80

9. Tumors in the Heart 81

Part III. Diseases Of The Digestive Organs

CHAPTER I.

Diseases of the Mouth.

1. Stomatitis 83

Vesicular 85

Papulous 86

Mycotic 87

CHAPTER II.

Diseases of the Pharynx.

1. Pharyngitis 89

Suppurative 89

Croupous 90

Diphtheritic 90

2. Paralysis of the Pharynx 91

3. Parasites in the Pharynx 93

Vin CONTENTS

CHAPTER III. Diseases of the Stomach and Bowels

1. Gastro-intestinal Catarrh of the Horse 94

2. Bloating in the Ox 97

3. Chronic or Habitual Tympany 100

Acute Dilatation of the Stomach 103

Simple Impaction of the Intestines 106

Impaction of the Small Bowel 106

Impaction of the Large Bowel 108

Impaction Complicated with Abnormal Displacement . 110

Displacement of Large Bowel 110

Displacement of Small Bowel Ill

Embolic Colic Ill

Spasmodic Colic 113

Worm Colic .113

5. Gastro-intestinal Catarrh of the Ox 114

6. Gastro-intestinal Catarrh of Sucklings 118

Simple 121

Croupous 124

Mycotic . 125

Toxic • 128

8. Traumatic Indigestion of the Ox 128

CHAPTER IV. Animal Parasites in the Stomach

1. Gastrophilus (Bots) 132

2. Spiroptera 133

Animal Parasites in the Intestines.

1. Tapeworms (Cestodes) 133

2. Round-worms (Ascarides) 135

3. Palisade-worms in the Intestines 136

Strongylus Armatus in the Horse ....... 136

Strongylus Tetracanthus in the Horse 137

Strongylus Contortus in Sheep 138

Strongylus Convolutus in the Ox 138

4. (Esophagostoma in the Intestines . . . . . . . . 138

5. Echinorhynchus Gigas of Swine 140

6. Oxyuris Curvula 140

7. Uncinariasis 141

CONTENTS IX

CHAPTER V. Diseases of the Liver

1. Jaundice 142

Obstructive . 142

Malignant 143

of Newborn 143

2. Hepatitis 144

Parenchymatous 144

Chronic Interstitial 145

Purulent 146

3. The Liver Fluke Disease (Distomatosis) ...... 147

4. Echinococcus Disease of the Liver . 148

5. Rupture of the Liver 150

6. Necrosis of the Liver . 150

7. Amyloid. Liver 151

8. Carcinoma of the Liver 151

9. Gall-stones (Cholelithiasis) 151

10. Parasites in the Liver 151

CHAPTER VI. Diseases of the Peritoneum

1. Peritonitis 152

2. Ascites 155

3. Tumors in the Peritoneum 157

4. Animal Parasites in the Peritoneum . 157

Part IV. Diseases Of The Reproductive Organs

1. Puerperal Septicemia 159

2. Parturient Paresis (Milk Fever) 161

3. Abnormalities in Sexual Desire 163

Nymphomania (Satyriasis) 163

Diminished Sexual Desire 165

4. Sterility 165

5. Impotency 167

CONTENTS

Part V. Diseases Of The Blood And Blood-producing

ORGANS.

1. Anemia 169

2. Leukemia . . 170

3. Pseudoleukemia (Hodgkin's Disease) 172

4. Hydremia 173

5. Hemophilia 173

6. Scurvy 173

7. Infectious Anemia of the Horse (Swamp Fever) .... 174

8. Azoturia 179

Part VIII. Diseases Of The Kidneys

1. Nephritis 199

Acute Parenchymatous 199

Chronic Interstitial 201

Purulent 202

Pyelonephritis 203

Bacterial 203

Calculous 204

2. Uremia 205

3. Hyperemia of the Kidneys 206

4. Renal Hemorrhage 206

5. Amyloid Kidney 207

6. Kidney Tumors 207

7. Hydronephrosis (Cystic Kidney) 207

8. Hematuria 208

9. Hemoglobinuria 208

10. Parasites in the Kidney 208

Eustrongylus Gigas 208

Xll

CONTENTS

Part IX. Diseases Of The Nervous System

CHAPTER I.

Diseases of the Brain.

General 209

1. Anemia of the Brain and its Membranes 211

2. Congestion of the Brain and its Membranes 212

3. Sun- and Heatstroke 213

4. Traumatic Injury and Concussion of the Brain .... 214

5. Lightning and Electric Stroke 215

6. Hemorrhage in the Brain and its Membranes (Apoplexy) . 216

7. Meningo-encephalitis 217

8. Encephalitis 221

Non-suppurative . . 221

Suppurative .......' 223

9. Infectious Meningo-encephalomyelitis (Borna Disease) . . 225

10. Chronic Hydrocephalus 227

11. Brain Tumors - . 228

12. Gid of Sheep 229

13. Infectious Bulbar Paralysis 231

CHAPTER II.

Diseases of the Spinal Cord.

1. Traumatic Injury of the Spinal Cord 234

2. Inflammation of Coverings of the Cord 236

3. Inflammation of Substance of the Cord (Spinal Myelitis) . 238

4. Compression of the Spinal Cord 240

5. Infectious Spinal Paralysis of the Horse 242

CHAPTER III. Functional Nervous Diseases

1. Vertigo

. . . . . 244

2. Epilepsy

3. Eclampsia . f

4. Catalepsy

5. Chorea

6. Spasms of the Diaphragm

CONTENTS xiii

Part X. Diseases Oe The Skin

1. Eczema 249

Horse 251

Swine 252

2. Urticaria 255

3. Alopecia . 256

4. Erythema 257

5. Pruritus 257

6. Trichorrhexis Nodosa 258

8. Pemphigus 258

9. Mange (Scabies) 259

Horse . 260

Sheep 261

Cattle . . . 264

Swine 264

10. Herpes (Ringworm) 265

12. Contagious Pustulous Dermatitis 267

13. Hypoderma Lineatum (Warble Flies) 268

16. Screw Fly (Compsomyia Macellaria) 270

17. Chicken Lice (Dermonyssus Avium) 270

18. Skin Filaria 270

Filaria Irritans 271

Filaria Hemorrhagica 271

19. Lip-and-leg Ulceration of Sheep 272

20. Bighead of Sheep 275 xiv CONTENTS

CHAPTER I. Acute General Infectious Diseases

1. Anthrax 279

2. Malignant Edema 285

3. Black-leg 287

4. Braxy (Gastromycosis Ovis) 290

5. Swine Erysipelas 292 of Cattle 296

Septic Pleuropneumonia of Calves 299

of Sheep 300

7. Takosis of Angora Goats 303

8. Septicemic Diseases of Newborn Animals 305

Dysentery of Sucklings 305

Pyosepticemia of Sucklings - 308

10. Infectious Fibrinous Pneumonia of the Horse 319

11. Purpura Hemorrhagica 322

12. Hog cholera 327

13. Rinderpest 333

14. African Horse-sickness 337

15. Heartwater . 338

CHAPTER V. Chronic Infectious Diseases

1. Tuberculosis , .... 389

2. Intestinal Paratuberculosis (Johne's Disease) 410

3. Caseous Lymphadenitis of Sheep 412

4. Actinomycosis 413

5. Glanders 417

6. Epizootic Lymphangitis 427

7. Ulcerous Lymphangitis of the Horse 429

9. Infectious Granular Vaginitis of Cattle 436

CHAPTER VI. Infectious Diseases due to Protozoa

Piroplasmosis of Cattle (Texas Fever) 440

Piroplasmosis of European Cattle 446

East African Coast Fever 448

Piroplasmosis of Horse 449

Piroplasmosis of Sheep . 450

Dourine 451

Surra 456

Nagana . 457

Mai de Caderas 458

3. Coccidiosis 459

Chapter I. Diseases Of The Nose And Adjacent

SINUSES.

RHINITIS. NASAL CATARRH.

Forms. — Depending upon the degree of inflammation the following clinical forms of rhinitis may be distinguished : Catarrhal (acute and chronic) .

Croupous.

Diphtheritic.

Follicular.

Acute Nasal Catarrh (Rhinitis, Acute Coryza). — Definition. — An acute catarrh of the air passages of the head. It may occur as a "primary affection or may be secondary to another disease.

Etiology. — Primary. — It is rarely due to the inhalation of foreign matter such as dust, chaff, grains, seeds, etc. Sponges placed in the nostrils to prevent discharge or to reduce the sound in roaring is an infrequent cause. Irritants, fumes, gases or smoke occasionally produce it. The common predisposing cause is cold. Rhinitis is most frequent during the changeable weather of the late fall and early spring. The exciting cause is undoubtedly infection.

Secondary. — Nearly all of the diseases of the respiratory tract are accompanied by rhinitis, as are specific infectious diseases such as strangles, influenza, hog cholera, glanders. 2

Symptoms. — The general condition of the patient is usually somewhat disturbed; it seems stupid, languid, and shows slight fever. The mucous membrane of the nose is swollen and reddened and at first drier than normal; later an irritant, watery discharge appears, which in a day or two becomes turbid and more profuse. In the earlier stages the patient sneezes frequently and rubs its nose against objects. The nasal discharge dries and forms crusts at the openings of the nostrils. In exceptional cases small round superficial erosions are noted on the mucous membrane, which usually heal in a few days. In severe cases there is conjunctivitis present. If the larynx is involved there is cough; if the pharynx, difficulty in swallowing. The submaxillary lymph glands in the horse are slightly swollen.

Course. — The course is usually rapid and the termination favorable. The condition in ordinary cases disappears in seven to ten days.

Treatment. — The acute catarrh seldom requires treatment. Protecting the patient from draughts and dust is all that is necessary in the average case. When, however, the discharge is profuse or the patient shows fever, injections into the nostrils of 1 to 2 per cent, creolin solution are recommendable. Inhalations of volatile substances are of value. Turpentine or benzoin (1 to 5 per cent, in form of steam) may be tried. The crust on the nostrils may be greased with vaseline. In man the "snuffing" of the fluidextract of hamamelis every two or three hours is much employed.

Chronic Nasal Catarrh (Chronic Rhinitis, Ozena). — Chronic rhinitis rarely develops from the acute. This form is nearly always secondary to some other disease involving the respiratory tract.

Etiology. — Bad teeth with filling of the maxillary or frontal sinuses with pus. It may also accompany glanders, tumors (polypi) in the nostrils, animal parasites (estrus larvre in sheep), chronic bronchitis, verminous bronchitis. In surgical conditions of the head such as necrosis of the turbinated bone, empyema of the sinuses, etc., nasal catarrh is noted.

Symptoms. — The principal symptom is nasal discharge, which varies greatly in quantity and character. The

RHINITIS— NASAL CATARRH 19

discharge may be quite copious, or, on the other hand, very limited. As a rule, even in a given patient, the discharge is greater at times (after a long drive and when the horse is unreined). In character the discharge may be mucous and viscid, or purulent or even blood-streaked (glanders, polypi). It is often fetid (teeth, necrosis of turbinated bones, polypi). The discharge, if limited, may dry at the nostril openings, forming green to brownish crusts (glanders) or it may flow over the upper lip depigmenting the skin over which it passes.

The mucous membrane assumes usually a leaden hue, although it may appear brown. It is at times swollen, nodular and pitted with round erosions or superficial ulcers. The swelling may interfere with breathing, causing nasal dyspnea with sound, heard particularly at inspiration. From a filling and distention of the turbinal bones with exudate the nasal septum may become atrophic and distorted through pressure leading to partial occlusion of the nasal passages. The submaxillary lymph glands become indurated and enlarged but usually do not adhere to the jaw.

Diagnosis. — While the diagnosis of chronic catarrhal rhinitis is not difficult, to determine whether it is primary or secondary often requires careful judgment. A thorough inspection of the teeth should be made in all cases, especially where the discharge is fetid and unilateral. Tumors may often be felt with the aid of a urinary horse catheter or nasal tube. A veterinary rhinolaryngoscope (Polonsky- Schindelka) is useful in diagnosis. If the tumor is of considerable size, the air current from the partially occluded nostril will be less in volume. A sudden increase in the discharge when the head is lowered after a drive speaks for sinus empyema or more rarely filling of the guttural pouches. Where glanders is suspected the complement-fixation, mallein, agglutination, precipitin or guinea-pig tests may be applied. (See Glanders.)

Treatment. — The treatment of chronic nasal catarrh is largely surgical (trephining sinuses, extraction of diseased teeth, removal of tumor, etc.). At any rate it is governed by the primary disease which the discharge accompanies.

The local treatment of the nose by irrigation or inhalation is of little value except in purely primary cases and then it must be persisted in for weeks before permanent healing is affected. The following combination may be tried:

1$ — Tannoformi 5vj

Mentholi 5ss

Alcohol (50 per cent.) Oj

Aqua dest Oss

M. D. S. — Apply as a nasal douche.

Croupous Rhinitis. — Definition. — An inflammation of the mucous membrane of the nasal chamber with the formation of pseudomembrane.

Occurrence. — Seen in the horse and ox. Enzootics have been noted in the horse.

Etiology. — It is attributed to the inhaling of irritant gases and smoke. It is undoubtedly due in many cases to microorganisms. It may follow suppurative mastitis or metritis in the mare and cow, and may be secondary to malignant head catarrh, purpura hemorrhagica, and strangles.

Symptoms. — An intense inflammation of the mucous membrane which is deep red and greatly swollen. Patches of gray or yellow red fibrinous membranes form. The false membrane sloughs off in a few days leaving behind raw bleeding surfaces which soon heal without scar. There is a free discharge, which may be blood-streaked and containing shreds of croupous membrane. The submaxillary lymph glands and vessels are swollen and sensitive. There may be nasal dyspnea. Temperature is elevated.

Course. — Usually ends in healing in about one week. ,

Treatment. — It is recommended to touch the affected parts with hydrogen dioxide, full strength, to each 2 ounces of which has been added a dram of sodium bicarbonate. Do not forcibly remove the membranes. Affected animals should be isolated.

Diphtheritic Rhinitis. — Definition. — A necrotic inflammation of the mucous membrane of the nasal cavities.

Occurrence. — Seen in horses and cattle. It is usually secondary to such infectious diseases as acute glanders, purpura hemorrhagica, malignant head catarrh.

RHINITIS— NASAL CATARRH 21

Etiology. — A primary diphtheritic rhinitis may result from the action of any mechanical, thermic, chemical or infectious irritant which is sufficiently intensive to destroy the mucous membrane. In all probability the necrosis bacillus is a factor. As noted, diphtheritic rhinitis may be secondary to certain infectious diseases.

Symptoms. — The condition is characterized by the appearance of yellowish-gray patches in the mucosa which when detached or sloughed leave behind deep, dark red or grayish-red ulcers. The borders of the ulcers are thickened and surrounded by a zone of reactive inflammation. The submaxillary lymph glands are swollen.

Diagnosis. — Glanders should be thought of and excluded before a diagnosis of "primary diphtheritic rhinitis" is made. In purpura hemorrhagica the differential diagnosis is less difficult (petechia?, typical cutaneous swellings). The eye affection absent in primary nasal diphtheritis is characteristic of malignant head catarrh of cattle.

Treatment. — See Croupous Rhinitis.

Follicular Rhinitis (Pustulous Coryza). — Definition. — An inflammation of the nasal mucous membrane involving particularly the mucous glands forming pustules and later ulcers. The sebaceous glands of the skin of the nostrils may also become affected.

Occurrence. — Peculiar to the horse. It may occur enzootically.

Etiology. — Undoubtedly microorganisms. The Streptococcus equi has been accused.

Symptoms. — The symptoms are those of a severe nasal catarrh with the presence of numerous small nodules of the size of flea-bite which appear on the nasal septum. By confluence large nodules may form. The nodules soon undergo puriform softening, become yellow and form ulcers which heal in a few days without leaving a scar. A similar eruption may occur on the skin of the nostrils and lips. The lymph vessels of the cheek are sometimes greatly distended, abscesses forming rapidly along their course. The submaxillary lymph glands become enlarged and sensitive. A follicular (granular) conjunctivitis may be present.

Diagnosis. — The disease might be confused with glanders. The benign course and rapid, clean healing of the ulcers make the differentiation not difficult.

Treatment. — Treat as in catarrhal rhinitis. Ulcers may be dressed with any strew-powder (iodoform, compound alum powder, etc.). The swollen lymph vessels may be smeared with gray mercurial ointment.

EPISTAXIS.

Definition. — Bleeding from the nose.

Etiology. — (a) Heredity. — In some families of horses it is an inherited predisposition. In such cases (hemophilia?) epistaxis occurs without apparent cause. It may follow overexertion in race horses (predisposition?).

(b) Traumatism. — Epistaxis commonly results from direct or indirect traumatism. Passing objects up into the nostrils (sponges, straw whisps, nasal tubes, etc.) is often followed by bleeding. In forcibly ejecting dust and foreign matter from the nose horses sometimes induce hemorrhage. Fractures of the jaw (maxillary process) and of the base of the cranium may be followed by nosebleed.

(c) Heart and Lung Diseases. — In animals suffering from chronic heart and lung diseases this diathesis is present.

(d) Pressure on Jugulars. — Continued pressure on the jugulars may be a cause.

(e) Infectious Diseases. — In many of the acute infectious diseases it is a symptom (anthrax, purpura hemorrhagica, glanders, septicemia), and in such blood diseases as leukemia, pseudoleukemia, anemia, etc.

(/) Tumors. — Tumors in the nasal chambers (angiomas, sarcomas) induce bleeding.

Symptoms. — The blood either drops from the nostril or flows in a thin stream. It is not foamy and not attended by dyspnea. There are no general symptoms unless the hemorrhage is copious or recurs frequently where it causes general anemia (pale mucous membranes, small rapid pulse, anxious expression, dyspnea). Repeated hemorrhages at frequent intervals may become fatal in six to nine days.

INFECTIOUS RHINITIS OF SWINE 23

Diagnosis. — It is usually not difficult to determine the origin of the hemorrhage but to find the cause may require a most careful examination of the patient. Pulmonary hemorrhages are characterized by a bright red, foamy bilateral nasal discharge accompanied by cough, dyspnea, and weak pulse. On auscultation of the chest, rales are heard. However, if from a nasal hemorrhage some of the blood is aspirated into the lungs, symptoms of pulmonary hemorrhage may be simulated, complicating the diagnosis. In gastric hemorrhage the blood is more or less clotted, brown in color, of acid reaction, and mixed with food particles. In the horse and ox it may be ejected thrbugh the nostrils, but in the hog and in carnivora it is vomited through the mouth.

Treatment. — The patient should be kept in a cool quiet place. If the hemorrhage is severe enough to warrant it, inject into the nostrils adrenalin in salt solution (1 to 5000). Tincture of ferric chlorid is serviceable. If injections do not suffice, tampon the nostril or nostrils with gauze soaked in adrenalin. In the horse and ox tracheotomy should be performed before plugging both nostrils. Intravenous injection of a 2 per cent, gelatin solution in salt solution has been effective. In slight hemorrhages turpentine may be given internally. When bleeding comes from an angioma in the septum, touching with lunar caustic may stop it.

INFECTIOUS RHINITIS OF SWINE.

Definition. — An infectious disease of the nose, ethmoid and brain of young pigs due to the Pseudomonas pyocyaneus, the microorganism of blue pus.

Natural Infection. — Takes place through the nose from the pigs rooting in infected straw, manure, etc.

Symptoms. — The prodromal symptoms are those of fever (loss of appetite, languor). Nasal symptoms soon appear. The patient passes air rapidly in and out of the nostrils, producing a snorting or sniffling sound; the snout is frequently rubbed against objects. There is bloody nasal discharge mixed with pus. The snout becomes edematous and swollen. In severe cases on about the third day of the attack symptoms of cerebral excitement occur, the pig showing rabiform symptoms and convulsions.

Course. — The usual course of the disease is from two to seven days. Sometimes it assumes a chronic form. Recovery is rare.

Diagnosis. — The high fever, rhinitis with pronounced brain symptoms and without deformity (bulging) of the facial bones are characteristic. It is distinguished from rachitis by the absence of fever, facial deformity and dropping of the hard palate in this disease. Actinomycosis and tuberculosis may cause thickening of the snout and nasal discharge in swine. The course, however, is chronic and there is no nasal hemorrhage. In doubtful cases a microscopic and bacteriological examination of the discharge may be made. It might be confused with hyperacute cases of hog cholera, in which at times epistaxis and brain symptoms occur. The epizootic character of this disease, the bowel lesions on postmortem and the absence of rhinitis make the differentiation usually easy.

Treatment. — Of little avail. In valuable pigs irrigating the nostrils with bichlorid solution (1 to 1000) may be tried. It is usually better to slaughter the affected animals and thoroughly disinfect the pens. As the disease is spread by the infected nasal discharge, a separation of the healthy from the sick is indicated.

ANIMAL PARASITES IN THE NOSE AND SINUSES OF THE HEAD.

Grub in the Head of Sheep. (Estrus Ovis.

Definition. — A catarrh of the nasal chambers and sinuses of the head due to the larvae of the bot fly, (Estrus ovis.

Occurrence. — Found in all countries where the sheep bot exists. Australia is said to be exempt. Few American sheep are free from grub.

Etiology. — The sheep are usually attacked by the parent bot fly during the hot season. It is said that the fly may even be active in winter in warm, sunny sheep folds.

ANIMAL PARASITES IN NOSE AND SINUSES OF HEAD 25

Life History. — The larvae are deposited by the swift-flying female bot on the margin of the sheep's nostrils, from whence they crawl up into the nasal chambers, cavities of the turbinal bones, ethmoid cells and even horn cores. It is possible that the brain is invaded in some cases. They attach themselves to the mucous membrane to feed and develop. They usually remain in the sheep about ten months, or until the following spring when they leave via nasal passages and reach the ground. In the soil in one or two days they pass into the chrysalis form out of which emerges in six to eight weeks the mature bot fly. The impregnated female bot seeks sheep herds. She usually hides in cracks and crevices in the sheep barn or on shrubbery or underbrush near the sheep pasture. Sheep try to avoid the attacks of the fly by running away from it with their noses held close to the ground or by grouping themselves in a great mass, their heads toward the centre. If the fly touches the nostril, the sheep will snort, stamp its feet and rub its nose on the forelegs or ground. They often seek dusty places in the pasture to avoid the fly. Once the larvae have gotten into the head, however, the sheep become quiet and remain so until the emigration of the parasite begins.

Symptoms. — If only one or two grubs are present, beyond a slight nasal discharge, the sheep may show no symptoms. When large numbers are in the head, however, the patients show profuse mucopurulent or even bloody nasal discharge, sneezing, snorting, sniffling, shaking the head and rubbing the nose against objects. In severe cases symptoms of vertigo occur, the patient staggering, reeling, and falling to the ground. Sometimes fatal convulsions are noted. Conjunctivitis may be present. As a rule, however, in about ten days after the first signs appear, and the larvae are expelled, the symptoms subside.

Diagnosis. — Grub-in-the-head may be confused with sturdy or gid (Ccenurus cerebralis). However, in sturdy the older sheep are attacked, there are no nasal symptoms and the forced movements of the patient are more pronounced. Gid is furthermore as yet an uncommon disease in the United States. In doubtful cases a postmortem or the microscopic examination of the discharge must decide.

From verminous bronchitis it may be distinguished by the absence of the cough and rales on auscultation so characteristic of bronchitis.

Treatment. — Very unsatisfactory. Trephining the sinuses and removing the larva? with forceps is only practicable in isolated cases and among valuable sheep. Nasal douches do not reach the larvae in the sinuses. In severe cases slaughter is the most economical disposition.

Prevention. — It is recommended to place in the pasture field a log in which a number of 2-inch augur holes have been bored. Salt is put in the bottom of each hole and around the margin tar. When the sheep attempt to get the salt the nostril becomes tar-smeared,, which partially, at least, protects against the bot fly. Allowing the sheep constant access to lime is of some value. Plowing a few furrows in the pasture serves to furnish dust in which the sheep may burrow their noses to avoid the fly.

CATARRH OF THE MAXILLARY AND FRONTAL SINUSES.

Definition. — A collection of mucopurulent exudate in the sinuses of the head.

Occurrence. — Commonest in the horse, but is seen in the ox. In cattle the frontal sinuses are usually involved.

Etiology. — Most frequently due to diseases of the teeth (dental caries; alveolar periostitis). In cattle it may follow dehorning. Certain infectious diseases such as glanders, malignant head catarrh, etc., may induce it.

Symptoms. — Nasal discharge which is often unilateral. It may be intermittent, copious or limited, and sometimes fetid. In some cases the bone covering the sinuses is atrophied and bulged outward, distorting the face. There may be conjunctivitis and partial occlusion of the lacrimonasal duct. Swelling of submaxillary lymph gland of the affected side is usually noted.

Diagnosis. — With a drill or gimlet bore into the suspected sinus.

Treatment. — Surgical.

TYMPANY OF GUTTURAL POUCH 27

CATARRH OF THE GUTTURAL POUCHES.

Definition. — An accumulation of exudate in the guttural pouches. In some cases the pouch is filled with solid, cheesy bodies, each of about the size of a bean (dried pus) . Distention of the pouch with gas may result from a decomposition of the exudate.

Etiology. —Rarely foreign bodies; spread of inflammation from neighboring organs; infection (glanders).

Symptoms. — Similar to those of chronic nasal catarrh. Swallowing and breathing may be interfered with. Swelling in the subparotid region.

Treatment. — Surgical.

TYMPANY OF GUTTURAL POUCH.

Definition. — A distention of the pouch with air or gas.

Occurrence. — Colts born with it. In older horses may also occur secondary to catarrh of pouches.

Etiology. — A congenital deformity of the tube or its valve. Secondary to catarrh of the pouches.

Symptoms. — An elastic, pneumatic swelling in the parotid region. May induce dyspnea, roaring, and dysphagia. Nasal discharge may fail.

Treatment. — Surgical. Rarely successful.

Chapter II. Diseases Of The Larynx

LARYNGITIS.

Clinically laryngitis may be classified into: Catarrhal (acute and chronic).

Croupous.

Edematous.

Catarrhal Laryngitis. — Definition. — A superficial inflammation of the mucosa of the larynx. Usually the upper part of the trachea and often the pharynx are also involved (laryngotracheal, laryngopharyngitis) .

Occurrence. — Catarrhal laryngitis is one of the commonest diseases of horses and cattle. It frequently assumes an enzootic form, being very prevalent during the changeable weather of spring and fall. The disease may be primary or secondary.

Etiology. — The causes of primary laryngitis are : refrigeration, inhalation of irritant dust, gases, ingestion of fermenting foods (brewer's grains, distillery slops, potato residue), continued bellowing of cattle, throat latch of bridle too tight, and primary infections.

Secondary laryngitis accompanies many of the infectious diseases, especially influenza and strangles of the horse, tuberculosis of the ox, cholera of swine, and verminous bronchitis of sheep. A spread of inflammation from neighboring organs (pharynx, trachea) may induce laryngitis. The causes of chronic catarrhal laryngitis are the same as those of the acute form, the irritant acting mildly but repeatedly or persistently.

Symptoms. — A dominant symptom of laryngitis is a dry, harsh cough which the patient seeks to suppress. It is especially noticeable when the animal is brought out into

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cold air or given a cold drink of water. Excitement also induces cough. The larynx is sensitive to pressure which may bring about a paroxysm of coughing. In some patients hoarseness is evident. On auscultation over the larynx stenotic, rough, sometimes whistling tones are heard which tend to diminish in intensity toward the chest. Nasal discharge is usually present. If the pharynx is also involved (laryngopharyngitis) there will be dysphagia. The lymph glands of the submaxillary region are swollen and sensitive. Except in secondary laryngitis the pulse and temperature remain about normal. Dyspnea is only present when there is marked swelling of the mucosa.

Diagnosis. — The diagnosis depends upon the presence of cough, sensitiveness of the larynx, mild fever, and the negative evidence adduced from a thorough examination of the lungs. Secondary laryngitis may be distinguished from primary forms by the high temperature, general depression of the patient and symptoms of the primary disease.