LIST OF PLATES 



[Note. Photographs marked with an asterisk (*) have been kindly lent by the 

 Scientific Press Company; those marked f are taken by permission from the 

 Report of Royal Commission on Sewage Disposal; and those marked J from 

 Reports to the London County Council. ] 



PLATE 



1. A Form of Room Temperature Incubator . . To face page 18 



2. Hot-air Steriliser and Blood-heat Incubator : . 24 



3. B. colt communis *; Proteus vulgaris J . . 46 



4. B. coli communis ; Gas Production in Gelatine f 50 



5. Small Centrifuge ; Sedgwick's Sugar-tube 74 



6. Air-Plate Culture from Labourer's Cottage . 76 



7. Air- Plate Cultures from Bakehouses 86 



8. Saccharomyces cerevisice ; Ascospores ; Pathogenic 



Yeast ..*... , 98 



9. Buchner's Tube ; Kipp's Apparatus for Anaerobic 



Culture . . . . 116 



10. A Vacuum Method of Anaerobic Culture . . 118 



11. Nitrous Organism; Nitric Organism; Nitrogen- 



fixing Organisms . . . . 128 



12. Nitrogen-fixing Bacteria in Nodule on Rootlet 



of Pea . '' 134 



13. B. tetani \*; B. mycoides*; Streptothrix actinomyces ; 



B. mallei. . . . . . 140 



14. Sewage Proteus, Organism and Plate Culture J . 154 



15. Sewage Streptococci t and Streptococcus pyogenes * . 156 



16. B. mesentericus, Organism and Plate Culture J . 158 



17. B. anthracis, from Septic Tank Liquor and in 



Gelatine Culture (impression) f . . 176 



18. B. tuberculosis (old culture); Tubercle Bacilli in 



Cow's Udder . 204 



