Inversive ferments, 115 Involution forms, 12, 66 Kipp's apparatus for producing hydrogen, 27, 139 Klebs-Löffler bacillus, 289 Koch's plate method, 40 -- postulates, 266 -- comma bacillus, 66 -- bacillus of tubercle, 276 Lactic acid fermentation, 115, 130, 185, 190, 221, 226 Lactose, 190 Leguminosæ, fixation of nitrogen by, 163 Leprosy, 308-313 Leptothrix, 8, 33 Leuconostoc, 17 Light, influence upon bacteria, 24-26, 70 Liquefaction of gelatine, 44, 241 Low yeasts, 125 Lymph, glycerinated calf, 252 Lyon's, Washington, disinfector, 328 Maceration industries, 135 Malaria, 177, 320 Malignant œdema, 19, 172 Mallein, 319 Mastitis, 184 Measles, 321 Meat, 234 Media, culture, 20 Merismopedia, 11 Method of examination, 43-47 Metropolitan water supply, 72 Miasmatic diseases, 176 Micrococcus, definition of, 8 -- agilis, 16 -- aquatilis, 53 -- casei amari, 226 Micrococcus Freudenreichii, 192 -- gonorrhœæ, 299 -- tetragonus, 299 -- viscosus, 192 Milk, bacteriology of, 178-213 -- absorptivity of, 180 -- sources of pollution, 181-184 -- number of bacteria in, 185 -- influence of temperature upon, 186 -- influence of time of standing, 187 -- fermentation bacteria in, 189 -- constitution of, 189-195 -- disease-producing power of, 195 -- and tuberculosis, 197-199, 228, 290 -- and typhoid, 199 -- and cholera, 200 -- and diphtheria, 201 -- and scarlet fever, 202 -- and thrush, 203 -- methods of preservation of, 205 -- and added antiseptics, 205, 206 -- filtration of, 206 -- sterilisation of, 207 -- pasteurisation of, 208-213 -- products, bacteria in, 213-227 -- examination of, 227 -- and economic bacteria, 215-220 -- sterile, 181 -- kinds of bacteria in, 188 -- chromogenic, 193 -- cooling processes, 207, 209 Moist chamber, 41 Moisture necessary for bacteria, 23 Motility, 14 Moulds, 116 Mycoderma aceti, 127 Nasal passages, bacteria in, 103 Natural purification of water, 69 Needles, platinum, 22, 24 Nitrates, 147, 154 Nitric organism, 157, 158 Nitrification, 76, 143-159 -- chemistry of, 144-148 -- stages in, 145 -- bacteria of, 152 Nitrifying organisms, cultivation of, 156 Nitrogen, fixation of, 144, 160-168 Nitrous organism, 154, 158 Nodules on roots, bacteria in, 163 Oidium albicans, 203 Oxygen necessary for bacteria, 26 Oysters and bacteria, 229-234 Paraform for disinfection, 334 Parasitism, 27, 162 Parietti's method, 62 Pasteurisation of milk, 208-213 Pasteur's treatment of rabies, 253-258 Perlsucht, 283 Petri dishes, 50 Phagocytosis, 247 Phosphorescence, 26, 241 Pigment, formation of, 241 Place of bacteria in nature, 5 Plague, 306-308 Plant diseases, 35 Plate cultures, 40-46 Platinum needles, 22, 24 Pleomorphism, 12 Pneumo-bacillus, 315