66 CLINICAL BACTERIOLOGY AND H^MATOLOGY 



The appearances in the plate culture are perhaps not quite 

 so characteristic, but they are manifested in impure cultures. 

 The young colonies of anthrax bacilli have a whorled appear- 

 ance, which has been compared to a barrister's wig or to the 

 head of Medusa (Fig. 18). The plate should be placed upon 

 the stage of the microscope, and examined for these colonies 

 with the low power. If one is found, a clean cover-glass 

 should be pressed upon it, lifted up with a needle, so as to 

 bring up the colony with it, fixed by heat, and stained with 

 carbol thionin or methylene blue. The colonies are most 

 characteristic after two days' incubation; at a later period the 

 gelatin is liquefied and spores are formed. 



A culture which presents these cultural and morphological 

 appearances, if taken from a disease having a clinical resem- 

 blance to any form of anthrax, may be considered to be one 

 of anthrax with almost absolute certainty, though other tests 

 (notably animal tests) would be applied in a laboratory. 



TUBERCLE 



The diagnosis of tuberculosis by bacteriological methods 

 (in the case of most morbid materials) is within the reach 

 of every practitioner; cultural methods are not used, and the 

 recognition of the bacillus is rapid, easy, and certain. 



The bacilli may be sought for in sputum, urine, pus, faeces, 

 or any morbid material. We will first describe the method of 

 staining which should be adopted, then the characters on 

 which the recognition of the bacillus depends, and, lastly, the 

 methods by which the films are prepared from the various 

 materials. 



STAINING THE TUBERCLE BACILLUS. 



Requisites. i. Slides, cover-glasses, forceps, and balsam. 



2. A Bunsen burner or spirit-lamp. 



3. Dilute sulphuric acid about 20 per cent. contained in a 

 wide-mouthed bottle or in a jar. This must be large enough 

 to admit a slide, but not large .enough to permit it to fall down 

 to the bottom. 



4. Carbol fuchsin. 



5. Methylene blue. (Saturated watery solution or Loffler's 

 blue.) 



