474 APPLICATION OF METHODS .OF BACTERIOLOGY 



2 grams, dissolved in 1 litre of boiling distilled water, 

 filtered, ond allowed to cool. It is again rinsed in water 

 and examined as a water-mount, or it may be dried and 

 mounted in balsam. 



When so treated the diphtheria bacterium appears as 

 faintly stained brown rods, in which from one to three 

 dark-blue granules are to be observed. The dark granules 

 are at one or both poles of the cell, are more or less oval, 



FIG. 83 



Bacterium diphtherias, stained by Neisser's method. 



and usually seem to bulge a little beyond the contour of the 

 bacterium in which they are located. (See Fig. 83.) From 

 Neisser's observations and those of others, 1 as well as from 

 personal experience, it seems safe in the vast majority of 



1 Frankel, Berliner klin. Wochetischrift, 1897, No. 50. Bergey, Publica- 

 tions of the University of Pennsylvania, New Series, 1898, No. 4. 



