I io GENERAL BACTERIOLOGICAL DIAGNOSIS. 



staining reactions. Does the bacterium stain with simple 

 watery solutions ? Does it require the use of stains 

 containing mordants ? How does it behave towards Gram's 

 method? It is important to investigate the first four 

 points both when the organism is in the fluids or tissues of 

 the body and when growing in artificial media, as slight 

 variations occur. It must also be borne in mind that 

 slight variations are observed according to the kind and 

 consistence of the medium in which the organism is 

 growing. (6) Is it motile and has it flagella ? If so, how 

 are they arranged ? (7) Does it form spores, and if so, 

 under what conditions as to temperature, etc.? 



2. Growth characteristics. Here the most important 

 points on which information is to be asked are, What are 

 the characters of growth and what are the relations of 

 growth (i) to temperature (2) to oxygen? These can be 

 answered from some of the following experiments : 



A. Growth on gelatine, (i) Stab culture. Note (a) 

 rate of growth ; (b) form of growth, (a) on surface, (j3) in 

 substance ; (c) presence or absence of liquefaction ; (d) 

 colour ; (e) presence or absence of gas formation and of 

 characteristic smell; (/) relation to reaction of medium. (2) 

 Streak culture. (3) Shake culture. (4) Plate cultures. 

 Note appearances of colonies (a) superficial, (>) deep. 

 (5) Growth in fluid gelatine at 37 C. 



B. Growth on agar at 37 C. (i) Stab. (2) Streak. 

 Also on glycerine agar, blood agar, etc. Appearances of 

 colonies in agar plates. 



C. Growth in bouillon, (a) character of growth, (b) 

 smell, (c) reaction. 



D. Growth on special media, (i) Solidified blood serum. 

 (2) Potatoes. (3) Lactose and other sugar media. Does 

 fermentation occur and is gas formed ? (4) Milk. Is it 

 curdled or turned sour? (5) Litmus media. Note changes 

 in colour. (6) Peptone solution. Is indol formed ? 



E. What is viability of organism on artificial media ? 



3. Results of inoculation experiments on animals. 



By attention to such points as these a considerable 



