GENERAL MORPHOLOGY AND PHYSIOLOGY. I 19 



anthracis from its contents. If we stain cover-glass 

 preparations of this bacillus by the method of 

 Gram, we get the following results. By the first 

 solution the rods are uniformly stained blue ; by 

 subjecting them to the iodine solution, the proto- 

 plasmic contents are contracted, 

 i. ...---. 



while the next solution, alcohol, 



^^^ 

 decolorises the sheath, which may ^ " 



be then stained in contrast with \ 

 eosin. 



The cell-wall may be either -^...*>.^ 

 pliable or rigid. Pliability is ob- FIG. 45. 



served in the long filaments, which F ^S^ 

 are endowed with a slow vermi- THRACIS, DOUBLE 



....... STAINED WITH GEN- 



cular movement, while rigidity TIAN VIOLET AND 

 accounts for the maintenance of EOSIN \ ^ heS 1 heatl ! 



was stained pink, and 



the characteristic form of several the ceil - contents 



i MI blue, x 1200. 



species, such as spirilla. 



Cell - contents. The cell - protoplasm yields 

 mycoprotein. In some it is homogeneous, and 

 in others granular. The action of the aniline dyes 

 indicates a close relation to nuclear protoplasm, 

 though all nuclear stains are not suitable for 

 bacteria. In some cases also, the bacteria remain 

 stained under the influence of a reagent, which 

 removes the colour from nuclei. The power of fixing 

 the stain is not always present, and indicates a 

 difference in the protoplasm of different species. 

 Thus in staining phthisical sputum, the nitric acid 

 removes the stain from all bacteria and bacilli 



