254 



Subject Index. 



Contact beds, 192. 



Counting, experimental error in, 



43> 44- 



Counting, procedure, 42. 

 Counts at different temperatures, 



63- 

 Counts at 20, 30, 40, and 50, 



173- 

 Cycle of nitrogen, 4, 5. 



Deep wells, bacteria in, 23, 24. 

 Dextrose broth as test for colon 



bacillus, 92. 



Dextrose broth, compared with 

 lactose bile, 148. 

 broth, as preliminary enrich- 

 ment medium, 149. 

 broth tubes, 175. 

 Diagnostic characters of B. coli, 



103. 



Dilution for colon test, 95. 

 Dilution of sample, 37. 

 Dissociation, effect of, 19. 

 Drigalski-Conradi medium, 69. 

 Driven wells, 23. 

 Dysentery organisms in water, 85. 



Effect of dilution, 37. 

 Eisner's medium, 68. 

 English sewages, 188. 

 Enrichment methods, 67, 69. 

 Enrichment methods, objections 



to, 68. 



Enumeration of bacteria, 25. 

 Esmarch tube, 44. 

 Examination of large samples, 94. 



of springs, 1 80. 



of water supply of Hartford, 55. 



Filtering action of soil, 22. 

 Filtration, efficiency of, 52. 



Filtration, mechanical, 53. 

 " Flaginac coli," 167. 

 Food, effect of, 18. 



supply, effect of, 14, 20. 



supply, effect of, 20. 

 Fuchsin agar, 70. 



Gas formation with B. coli, 90. 



ratio, atypical, 142. 



ratio for B. coli, 105, 141. 

 Gelatin, phenolated, 68. 

 Gelatin-plate count, 175. 

 Gelatin, potato, 68. 

 Gelatin tube, 108. 

 Glass, effect of composition of, 35. 

 Glucose-formate broth, 92. 

 Green plants, N-requirements, 3. 

 Ground water 7. 

 Ground-waters, bacteria in, 22. 

 Ground-waters, classes of, 22. 



Hartford, examination of water 



supply of, 55. 

 Hog cholera bacillus, 163. 

 Hog cholera group, 164. 



Iceing, effect on samples, 36. 

 Impounding, effect of, 10. 

 Increase of bacteria in Toronto 



water supply, 55. 

 Incubation, 41, 212. 

 Incubation, effect of period of, on 



count, 43. 

 Incubator, necessity for moisture 



in, 41. 

 Incubator, necessity for oxygen 



in, 41. 



Incubation, period of, 42. 

 Incubation temperature, 41. 

 Indol test, 108, 211. 



