QUESTIONS 163 



17. Describe method of obtaining a pure culture from bacteria present in the 

 circulating blood of an animal. 



18. How is a microscopic preparation made from fluid culture media when 

 only a few microorganisms are thought to be present? 



19. Describe a bacteriologic postmortem examination with the preparation of 

 cultures from the heart's blood and from various internal organs. 



20. What is meant by a subculture ? What other term for subculture is in 

 common use? 



21. Why is it necessary to make subcultures frequently? 



22. What is meant by the first, the third, the twentieth generation of a patho- 

 genic bacterium ? 



23. How should a culture be labeled? How a microscopic stained preparation? 



24. What is a streak culture ? What is a stab culture ? 



25. How is a "shake" culture prepared and for what purpose? 



26. How would you prepare a pure culture from a discharge containing glanders 

 or tubercle bacilli? Give reasons for the procedure adopted. 



27. What is an anaerobic culture? 



28. What are the principles of the methods used in preparing anaerobic cultures ? 



29. What was Koch's first method to exclude atmospheric air from a plate 

 culture ? 



30. How is the stick culture method practised for the preparation of anaerobic 

 cultures ? 



31. What is the simplest method of raising anaerobic bacteria in fluid culture 

 media ? 



32. Describe the method of using a Kipp gas generator for the development of 

 hydrogen gas. 



33. What precautions are necessary in mixing water and sulphuric acid and 

 why? 



34. What is a Novy jar. Describe its use in connection with a Kipp apparatus. 



35. What chemical means are used for removing the oxygen from the atmos- 

 pheric air in a closed vessel? 



36. How are these chemical means made use of for a single culture tube and 

 how for a number of them and for Petri dishes? 



37. How is an anaerobic culture prepared in a hen's egg? 



38. Describe Wright's method of preparing anaerobic cultures in completely 

 filled glass tubes. 



39. Describe Wright's modification of the Buchner method of raising anaerobic 

 cultures in tubes. 



40. What other names are in use for a bacterial brood oven? 



41. What is the construction of such apparatus? 



42. What is a micro-gas lamp? 



43. What is a thermoregulator? Describe the glass mercury thermoregulator. 



44. How is it adjusted for use with an incubator kept at 37 C? 



45. Describe the method to start an incubator to be kept at 37 C. 



46. How are the incubator gas hose and glass tubes inspected for leaks ? 



47. Under what circumstances is it particularly important to keep the thermo- 

 stat always at a uniform temperature? 



48. Describe method used to obtain germ-free filtrates of bacterial cultures. 



