Subject Index. 



Inorganic constituents, effect of, 



19. 



Interpretation of results, 46. 

 Intestinal organisms, 59. 

 Intestinal bacteria multiplication 



in water, 21. 

 Interpretation of results, effect of 



warm weather upon, 65. 

 Isolation of B. coli, 98. 

 of B. sporogenes, 161. 

 of specific pathogenes, 67. 



Lactic acid bacteria, 119. 



Lactose bile, 147. 



Lactose bile, as preliminary en- 

 richment medium, 149. 

 bile, compared with dextrose 



broth, 1 1 8. 

 decomposition of, 59. 

 neutral red broth, 151. 



Lactose-bile, use of, with polluted 

 waters, 92, 93. 



Large samples, examination of, 94. 



Light, effect of, 14. 



Litmus-lactose-agar, 59. 



Litmus-lactose-agar for isolation 

 of B. coli, 97. 



Litmus-lactose-agar plate, 88. 



Litmus-lactose-agar plates, incu- 

 bation of, 98. 



Litmus-lactose-agar, possible error 

 with, 99. 



Litmus-lactose-agar, use of, 174. 



Malachite-green agar, 70. 

 Meat infusion, variability of, 41. 

 Mechanical filters compared with 



sand filters, 54. 

 Mechanical nitration, 53. 



Media, preparation of, 203, 208, 

 209. 



ingredients of, 203, 204. 



reaction of, 205. 



sterilization of, 204. 



storage of, 206. 



Medium, importance of compo- 

 sition, 38, 39. 

 Milk, 210. 



Minimal nutrients, 49. 

 Motility of B. coli, 104. 



Nahrstoff agar, 25, 26, 27. 

 Nahrstoff -gelatin ratio, 27. 

 Nahrstoff media, effect of, 26, 27. 

 Neutral red, 150. 



Neutral red broth, as presump- 

 tive test, 150. 



Newport, R. I., typhoid at, 55. 

 Nitrate solution, 210. 

 Nitrates, formation by bacteria, 4. 

 Nitrification, 4. 

 Nitrifying organisms, 200. 

 Nitrite test, 108. 



Nitrites, formation by bacteria, 4. 

 Nitrogen, cycle, 4, 5. 

 Nitroso-indol reaction, 83. 

 " Normal inhabitants," 58. 

 Normal waters, 49. 

 Nutrients, minimal, 49. 



Objectionable aliens, 58. 

 Ocean, bacteria in, 13. 

 Organisms, acid forming, 60. 

 Organisms, intestinal, 59. 

 Osmotic pressure, 14. 

 Overturns, effect of, 12. 

 Ox bile, 146. 



as culture medium, 146. 



as presumptive test, 147. 



