404 BACTERIOLOGY. 



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

 momited in balsam. 



When so treated the diphtheria bacillus appears as 

 faintly stained brown rods, in which from one to three 

 dark-blue granules are always to be observed. The 

 dark granules are at one or both poles of the cell, are 

 more or less oval, and usually seem to bulge a little 

 beyond the contour of the bacillus in which they are 

 located. (See Fig. 70.) From Neisser's observations 

 and those of others/ as well as from personal experience, 

 it seems safe in the vast majority of cases to regard all 

 bacilli that do not stain in the way described as distinct 

 from bacillus diphtherice.^ 



Note. — Prepare cover-slip preparations from the 

 mouth-cavities of healthy individuals and from those 

 having decayed teeth. Do they correspond in any way 

 with those made from diphtheria ? Do the same with 

 different forms of sore-throat. Do the peculiarities of 

 any of the organisms suggest those of the bacillus of 

 diphtheria? Wherein is the difference? 



In cultures and cover-slips made from both diph- 

 theritic and from innocent sore-throats are any organ- 

 isms almost constantly present ? Which are they, and 

 what are their characteristics ? 



Which are the predominating organisms in the an- 

 ginas of scarlet fever? 



Do these organisms simulate, in their cultural and 

 morphological peculiarities, any of the different species 

 with which you have been working ? 



' rriinke] : Berliner klin. Wochenschrift, 1897, No. 50. 

 2 Bergey ; Publications of the University of Pennsylvania, New 

 Series, No. 4, 1898. 



