86 PRACTICAL BACTERIOLOGY 



10. Is the normal reaction of the medium altered by its growth ? 

 Is its growth accompanied by the production of indol ? Is the indol 

 associated with the coincident production of nitrites ? 



11. Is its growth accompanied by the production of gas, as 

 evidenced by the appearance of gas bubbles in the media, both in 

 media containing fermentable sugars and those from which these 

 bodies are absent ? When cultivated in sugar bouillon in the 

 fermentation tube, what production of gas is evolved under known 

 conditions ? How much of this gas is carbonic acid and how much is 

 explosive ? 



12. At what temperature does it thrive best, and the lowest and 

 highest temperature at which it will develop ? What is its thermal 

 death-point, both by steam and dry-air methods of determining this 

 point ? 



13. What is its behaviour when exposed to chemical disinfectants 

 and antiseptics ? Does it withstand drying and other injurious 

 influences, both in the vegetative and spore stages ? The germicidal 

 value of the blood serum of different animals may also be tried 

 upon it. 



14. Its pathogenic powers modes of inoculation by which these 

 are demonstrated ; quantity of material used in inoculation ; duration 

 of the disease and its symptoms ; lesions produced, and distribution 

 of the bacteria in the inoculated animal ; which animals are 

 susceptible and which immune, and the character of its pathogenic 

 activities ? Variations in virulence, and the probable cause to which 

 they are due. Can they be produced artificially and at will ? 



15. The detection of specific, toxic, and immunizing products of 

 growth. 



16. Its behaviour when exposed to the influence of blood serum of 

 animals immunized from it; also its behaviour when mixed with 

 serum from an animal in the height of infection by it. Are the 

 relations between the organism and the serum constant and specific ? 



