TABLE OF CONTENTS XV 



PAGE 



Section 9. Examination of Milk for Molds and 



Yeasts 160 



Section 10. Examination for Leukocytes in Milk . 160 



Section 11. A Study of Groups of Bacteria in Milk . 162 

 Part VI. The Bacteriological Examination of Soil 

 Section i. Quantitative Determination of Bacteria 



and Spores in Soil 165 



Section 2. A Study of the Peptonization of Proteins 



by Soil Bacteria 168 



Section 3. The Formation of Amido Compounds and 



Ammonia 170 



Section 4. The Formation of Nitrites from Ammonia 



and Isolation of Nitrite Bacteria . . . 171 

 Section $• The Formation of Nitrates from Nitrites 



and Isolation of Nitrate Bacteria . . . 174 

 Section 6. The Assimilation of Free Atmospheric 



Nitrogen and Isolation of the Bacteria . 175 

 Section 7. The Reduction of Nitrates to Nitrites and 



Isolation of the Bacteria 177 



Section 8. The Reduction of Nitrates to Free Nitro- 

 gen . . 177 



Section 9. Growing Legumes in Sand and in Sand 



Inoculated with Legume Bacteria . . 178 



Part VII. Molds, Yeasts, Torulae, and Acetic-Acid 

 Bacteria 



Section i. Preparation of Culture Media . . . 181 



Section 2. A Study of Molds 182 



Section 3. A Study of Yeasts ..;.... 185 



Section 4. Examination of Baker's Yeast ... . 190 



Section s- Examination of Yeast of Salt-rising Bread igi 



Section 6. A Study of Torulae 192 



Section 7. A Study of Acetic-Acid Bacteria . . . 192 



Appendix 



Dilution Tables 197 



Table of Weights and Measures . . .... 198 



Table of Centigrade and Fahrenheit Thermometers . 198 



Index 203 



