TABLE OF CONTENTS 



xv 



Section 9 



Section 

 Section 

 PART VI. 

 Section 



Section 

 Section 

 Section 

 Section 

 Section 

 Section 

 Section 

 Section 



Examination of Milk for Molds and 

 Yeasts 160 



10. Examination for Leukocytes in Milk . 160 



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

 THE BACTERIOLOGICAL EXAMINATION OF SOIL 



1. Quantitative Determination of Bacteria 

 and Spores in Soil 165 



2. A Study of the Peptonization of Proteins 



by Soil Bacteria 168 



3. The Formation of Amido Compounds and 

 Ammonia 170 



4. The Formation of Nitrites from Ammonia 

 and Isolation of Nitrite Bacteria . . . 171 



5. The Formation of Nitrates from Nitrites 



and Isolation of Nitrate Bacteria . . . 174 



6. The Assimilation of Free Atmospheric 

 Nitrogen and Isolation of the Bacteria . 175 



7. The Reduction of Nitrates to Nitrites and 

 Isolation of the Bacteria 177 



8. The Reduction of Nitrates to Free Nitro- 

 gen .. 177 



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 5. Examination of Yeast of Salt-rising Bread 191 



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 



