14 APPLIED BACTERIOLOGY 



n the middle of the cover-slip, as well as round the edges, 

 he bacteria will be found equally well stained, the clumps 

 eing surrounded by a zone of delicate fringing flagella, 

 ach being well stained and distinctly outlined from its 

 allows. If a clear preparation is desired, the stain, after 

 lixing, may be filtered ; but Dr. Pitfield has found that the 

 lost reliable method is to use the unfiltered stain. In the 

 ase of the former, a clear fluid is produced without the 

 etritus, etc., being precipitated on the glass around the 

 licro-organisms, and all the flagella are stained, but not 

 3 distinctly as with the unfiltered solution. If the filtered 

 tain is used, a second stain of aniline water, containing 

 entian violet, had better be used, which should be applied 

 ut a moment and then washed off, thus leaving a clean 

 eld, showing only the bacteria lightly stained, with their 

 agella still more lightly coloured. In examining the 

 ifferent bacteria. Dr. Pitfield found that the bacillus of 

 typhoid fever, the colon bacillus, the cholera bacillus, and 

 le bacillus of hog cholera, each stained well by this 

 lethod, and without the addition of any acid or alkali to 

 le mordant such as Loffler uses. The bacillus of typhoid 

 )ver showed the flagella most beautifully, and there seemed 

 Qe flagellum to each cell that stained more deeply than the 

 thers and appeared larger and stronger. 



HE Examination of Oeganisms in Sections op Tissues. 



The examination of bacteria in the tissues of the animal 

 ibject, it is needless to say, is of vast importance in medical 

 3search. Not only is much learnt of their position in the 

 ssues, but also of the manner by which the organisms 

 lin access to the body. In order to examine the tissues 

 : organs of the animal body for the presence of micro- 

 rganisms, it is necessary to first prepare the thinnest 



