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