REGISTRATION OF BACTERIA 59 



contains spores of bacteria which are highly resistant to heat 

 and not readily killed by steaming. 



4. Identification, Classification, and Registration 

 of Bacteria. In determining the specific character of 

 a bacterium, its morphological and physiological features 

 must be thoroughly examined, and in describing a new 

 organism these features must be exhaustively studied 

 and the results accurately recorded in order to facilitate 

 future comparison and reference. No description should 

 be considered complete which does not contain full 

 information respecting the following points : 



(a) The form, size, and motility of the organism. 



(<) The presence or absence of spore formation ; the 

 shape, size, and position of the spores in the parent cells. 



(c) Staining quality by Gram's and other methods. 



(d) The form and colour of the surface and deep 

 colonies in gelatine and agar media. Is the ge-latine 

 liquefied ? 



(e) The aerobic or anaerobic character and the growth 

 and behaviour at low and high temperatures (20 and 

 37 C. respectively). 



(/) Growth on potato. 



(g) Action upon milk : coagulation and acid formation. 



(^5) Its action in broths containing various sugars ; 

 the power of forming acids and gas in these media. Its 

 relative growth in broth with + 10, neutral and - 10 

 reactions. 



(/) The power of reducing nitrates with the produc- 

 tion of gas. 



The practical testing of the various characters of the 

 organisms is dealt with in subsequent exercises. 



A simple and convenient method of classifying and 

 registering the character of bacteria which is especially 



