BACTERIA IN WATER 37 CHAPTER III BACTERIA IN THE AIR 96 CHAPTER IV BACTERIA AND FERMENTATION 111 CHAPTER V BACTERIA IN THE SOIL 137 CHAPTER VI BACTERIA IN MILK, MILK PRODUCTS, AND OTHER FOODS 178 CHAPTER VII THE QUESTION OF IMMUNITY AND ANTITOXINS 240 CHAPTER VIII BACTERIA AND DISEASE 264 CHAPTER IX DISINFECTION 322 APPENDIX 337 ILLUSTRATIONS [Illustrations starred (*) are reproduced by permission of the Scientific Press from Drs. Spitta and Slater's _Atlas of Bacteriology_.] PAGE VARIOUS FORMS OF BACTERIA 9 SARCINA 10 NORMAL AND PLEOMORPHIC FORMS OF TUBERCLE 13 BACILLI, SHOWING FLAGELLA 15 VARIOUS FORMS OF SPORE FORMATION AND FLAGELLA 18 POTATO IN A ROUX TUBE PREPARED FOR CULTIVATION 22 STAPHYLOCOCCUS PYOGENES AUREUS INCUBATOR _to face_ 22 CULTURE MEDIA READY FOR INOCULATION 23 INOCULATING NEEDLES 24 PASTEUR'S LARGE INCUBATOR FOR CULTIVATION AT ROOM TEMPERATURE _to face_ 24 METHOD OF PRODUCING HYDROGEN BY KIPP'S APPARATUS FOR CULTIVATION OF ANAËROBES 27 ANAËROBIC CULTURE 28 KOCH'S STEAM STERILISER 31 LEVELLING APPARATUS FOR KOCH'S PLATE 40 MOIST CHAMBER IN WHICH KOCH'S PLATES ARE INCUBATED 41 HOT-AIR STERILISER 42 THE HANGING DROP 44 DRYING STAGE FOR FIXING FILMS 45 TYPES OF LIQUEFACTION OF GELATINE 47 WOLFHÜGEL'S COUNTER 49 PETRI'S DISH 50 BERKEFELD FILTER 52 APPARATUS FOR FILTERING WATER TO FACILITATE ITS BACTERIOLOGICAL EXAMINATION _to face_ 52 BACTERIA OF TYPHOID FEVER 56 BACILLUS COLI COMMUNIS 60 THE COMMA-SHAPED BACILLUS OF CHOLERA 66 *BACILLUS TYPHOSUS _to face_ 66 *BACILLUS TYPHOSUS " 66