XVlll CONTENTS. 



PAGE 



§ Ifi. Suspended Particles in Air and Water ; their relation to 



Bactena ..... .... 75 



§ 17. Recent Experiments on Heterogenesis .... 84 



§ 18. Experiments with Filtered Air 85 



§ 19. Experiments with Calcined Air 88 



§ 20. Infusions withdrawn from Air . . . . . , 90 



§ 21. The Germ Theory of Contagious Disease ... 91 

 § 22. Experiments with Hermetically-sealed Vessels . . . 94 

 § 23. Conditions as to the Temperature and Strength of In- 

 fusions .......... 98 



§ 24. Developmental Power of Infusions and Solutions : Air- 

 germs contrasted with Water-germs . . . . 101 



§ 25. Diffusion of Germs in the Air 107 



§ 26. Tray of one hundred Tubes 110 



§ 27. Some Experiments of Pasteur and their Relation lo Bac- 

 terial Clouds 121 



Note I. Action of Bacteria upon a Beam of Light . 127 



Note II. Fluorescence of Infusions 128 



FURTHER RESEARCHES ON THE DEPORTMENT AND 

 VITALITY OF PUTREFACTIVE ORGANISMS. 



§ 1. Introduction 131 



§ 2. Experiments of Pasteur, Roberts and Cohn . . . 135 

 § 3. Hay-Infusions. Preliminary Experiments with Pipette- 

 bulbs 138 



§ 4. Hay-Infusions. Experiments with Cohn's Tubes . . 144 



§ 5. Hay-Infusions (in Closed Chambers) 146 



§ 6. Desiccation of Germs. New Hay and old . . . 148 

 § 7. Hay-Infusions. Further Experiments with Closed 



Chambers 150 



§ 8. Experiments with Soaked Hay 154 



§ 9. Infusions of Fungi 158 



§ 10. Infusions of Cucumber, Beetroot, &c 161 



§ 11. New Experiments on Animal Infusions. Contradictory 



results 165 



§ 12. Infusions protected b}- Glass Shades containing Calcined 



Air 169 



§ 13. Further Precautions against Infection . . . .171 



§ 14. Experiments in the Royal Gardens, Kew . . . . 174 



§ 15. Exj)eriments on the Roof of the Royal Institution . . 177 

 § 16. Preliminary Experiments on the Resistance-limit of 



Germs to the temperature of Boiling Water . . 180 



