63 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



young colonies of anthrax bacilli have a whorled appearance, 

 which has been compared to a barrister's wig or to the head of 

 Medusa (Fig. 21). 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 resemblance 

 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 exudates) 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 other 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.) 



6. A metal (iron or copper) plate. The exact dimensions do 

 not matter, but 8 by 4 by i inches is a convenient size. It should 

 be mounted upon a tripod. This slab is not absolutely necessary, 

 but it is a very great advantage. 



