382 BACTERIOLOGY. 
will be seen with the 1/12 oil immersion lens—either 
an enormous number of characteristic Léffler-bacilli, 
with a moderate number of cocci, or a pure culture of 
cocci, mostly in pairs or short chains (see Streptococ- 
cus). Ina few cases there will be an approximately 
even mixture of Léffler bacilli and cocci, and in others 
a great excess of cocci. Beside these, there will be 
occasionally met preparations in which, with the cocci, 
there are mingled bacilli more or less resembling the 
Léffler bacilli. These bacilli, which are usually of 
the pseudodiphtheria type of bacilli (see Fig. 46), are 
especially frequent in cultures from the nose. 
In not more than one case in twenty will there be 
any serious difficulty in making the diagnosis, if the 
serum in the tube was moist and had been properly 
inoculated. In such a case another culture: must be 
made or the bacilli plated out and tested in pure 
culture. 
Direct Microscopical Examination of the Exudate. 
An immediate diagnosis without the use of cultures 
is often possible from a microscopical examination of 
the exudate. This is made by smearing a slide or 
cover-glass with a little of the exudate from the swab, 
drying, heating, staining, and examining it microscop- 
ically. This examination, however, is much more diffi- 
cult, and the results are more uncertain than when the 
covers are prepared from cultures. The bacilli from 
the membrane are usually less typical in appearance 
than those found in cultures, and they are mixed with 
fibrin, pus, and epithelial cells. They may also be 
very few in number in the parts reached by the swab, 
or bacilli may be met with which closely resemble the 
Liffler bacilli in appearance, but which differ greatly 
