Vlll 



CONTENTS 



Exercise 13. - To show the Action of Proteolytic Enzymes upon 



Casein. 188 



Exercise 14. To Show the Action of Enzymes upon Starch 189 



Exercise 16. To Show the Action of Reducing Enzymes 190 



Exercise 16. To Show the Action of the Enzyme Catalase 191 



Exercise 17. To Demonstrate the Oxidizing Enzyme of Vinegar 



Bacteria 192 



Exercise 18. To Demonstrate the Necessity for an Activator 



for the Enzymic Action of Rennet 193 



Exercise 19. Effect of Concentrated Solutions upon Microor- 

 ganisms 195 



Exercise 20. The Effect of Desiccation upon Bacteria 197 



Exercise 21. The Determination of the Optimum, Maximum 

 and Minimum Temperature Requirements for 

 Certain Organisms 198 



Exercise 22. The Effect of Freezing upon Spore-forming and 



Non-spore-forming Bacteria 199 



Exercise 23. The Determination of. the Thermal Death Point of 

 a Spore-forming and a Non-spore-forming Or- 

 ganism 200 



Exercise 24. To Determine the Relative Effect of Moist and 



Dry Heat on Bacteria 202 



Exercise 25. To Determine the Effect of Pasteurization upon the 



Growth of Microorganisms 203 



Exercise 26. To Illustrate the Effect of the Reaction of the 



Nutrient Medium upon Microorganisms . : 205 



Exercise 27. To Determine the Effect of Diffused Light upon 



Molds 206 



Exercise 28. To Show the Influence of Direct Sunlight upon the 



Growth of Microorganisms 208 



Exercise 29. Determination of the Phenol Coefficient of Some 



Common Disinfectants 210 



Exercise 30. To Determine the Action of Formaldehyde upon 



the Microflora of Milk 213 



Exercise 31. To Illustrate Symbiosis 214 



Exercise 32. To Illustrate One of the Phases of Mutual Rela- 

 tionship of Microorganisms 215 



Exercise 33. To Demonstrate the Effect of the Metabolic Prod- 

 ucts of Bact. Lactis Acidi on its Activities 217 



