Common Diseases of Farm Animals | Page 2

Placenta of cow. 20. A case of milk-fever. 21. Milk-fever apparatus. 22. A case of catarrhal cold. 23. Photograph of model of horse's heart. 24. Elephantiasis in horse. 25. Photograph of model of horse's brain. 26. Unilateral facial paralysis. 27. Bilateral facial paralysis. 28. Skeleton of horse. 29. Photograph of model of stifle joint. 30. Atrophy of the muscles of the thigh. 31. Shoulder lameness. 32. Shoe-boil. 33. Sprung knees. 34. Splints. 35. Bones of digit. 36. Photograph of a model of the foot. 37. Foot showing neglect in trimming wall. 38. A very large side bone. 39. A case of navicular disease. 40. An improperly shod foot. 41. Toe-cracks. 42. Quarter-crack caused by barb-wire cut. 43. Changes occurring in chronic laminitis. 44. Atrophy of the muscles of the quarter. 45. String-halt. 46. A large bone spavin. 47. Normal cannon bone and cannon bone showing bony enlargement. 48. Bog spavins. 49. Thorough pin. 50. Curbs. 51. Head of young horse showing position and size of teeth. 52. Longitudinal section of incisor tooth. 53. Cross-section of head of young horse, showing replacement of molar tooth. 54. Transverse section of incisor tooth 55. Transverse sections of incisor tooth showing changes at different ages. 56. Teeth showing uneven wear occurring in old horses. 57. Fistula of jaw. 58. A large hock caused by a punctured wound of the joint. 59. A large inflammatory growth following injury. 60. Fistula of the withers. 61. Shoulder abscess caused by loose-fitting harness. 62. A piece of the wall of the horse's stomach showing bot-fly larvae attached. 63. Biting louse. 64. Sucking louse. 65. Nits attached to hair. 66. Sheep-tick. 67. Sheep scab mite. 68. Sheep scab. 69. A severe case of mange. 70. Liver flukes. 71. Tapeworm larvae in liver. 72. Tapeworms. 73. Tapeworm larvae in the peritoneum. 74. Thorn-headed worms. 75. Large round-worm in intestine of hog. 76. Lamb affected with stomach worm disease. 77. Whip-worms attached to wall of intestine. 78. Pin-worms in intestine. 79. A hog yard where disease-producing germs may be carried over from year to year. 80. Carcass of a cholera hog. 81. Kidneys from hog that died of acute hog-cholera. 82. Lungs from hog that died of acute hog-cholera. 83. A piece of intestine showing intestinal ulcers. 84. Cleaning up a hog lot. 85. Hyperimmune hogs used for the production of anti-hog-cholera serum. 86. Preparing the hog for vaccination. 87. Vaccinating a hog. 88. Koch's Bacillus tuberculosis. 89. A tubercular cow. 90. Tubercular spleens. 91. The carcass of a tubercular cow. 92. A section of the chest wall of a tubercular cow. 93. A very large tubercular gland. 94. A tubercular gland that is split open. 95. Caul showing tuberculosis. 96. Foot of hog showing tuberculosis of joint. 97. Staphylococcus pyogenes. 98. Streptococcus pyogenes. 99. Bacillus of malignant oedema, showing spores. 100. Bacillus of malignant oedema. 101. Bacillus bovisepticus. 102. A yearling steer affected with septicaemia haemorrhagica. 103. Bacillus anthracis. 104. Bacillus necrophorus. 105. Negri bodies in nerve-tissue. 106. A cow affected with foot-and-mouth disease. 107. Slaughtering a herd of cattle affected with foot-and-mouth disease. 108. Disinfecting boots and coats before leaving a farm where cattle have been inspected for foot-and-mouth disease. 109. Cleaning up and disinfecting premises. 110. Bacillus tetani. 111. Head of horse affected with tetanus. 112. A subacute case of tetanus. 113. Streptococcus of strangles. 114. Bacillus mallei. 115. Nasal septum showing nodules and ulcers. 116. Streptococcus pyogenes equi. 117. A case of "lumpy jaw". 118. The ray fungus. 119. Bacillus of emphysematous anthrax. 120. Cattle tick (male). 121. Cattle tick (female). 122. Blood-cells with Piroplasma bigeminum in them. 123. Bacillus avisepticus.

PART I.--INTRODUCTORY

CHAPTER I
GENERAL DISCUSSION OF DISEASE
Disease is the general term for any deviation from the normal or healthy condition of the body. The morbid processes that result in either slight or marked modifications of the normal condition are recognized by the injurious changes in the structure or function of the organ, or group of body organs involved. The increase in the secretion of urine noticeable in horses in the late fall and winter is caused by the cool weather and the decrease in the perspiration. If, however, the increase in the quantity of urine secreted occurs independently of any normal cause and is accompanied by an unthrifty and weakened condition of the animal, it would then characterize disease. Tissues may undergo changes in order to adapt themselves to different environments, or as a means of protecting themselves against injuries. The coat of a horse becomes heavy and appears rough if the animal is exposed to severe cold. A rough, staring coat is very common in horses affected by disease. The outer layer of the skin becomes thickened when subject to pressure or friction from the harness. This change in structure is purely protective and normal. In disease