THE PLEURA. 123 
scopical examination, the inference is that the case is 
tubercular. Ifa cultural examination is also negative 
the inference becomes almost a certainty. 
Having these facts in view the practitioner is recom- 
mended to proceed to examine cases of purulent pleurisy 
in the following manner :—The pus is to be withdrawn 
with a hypodermic needle or exploring syringe, and a 
few drops deposited at once on the surface of a culture 
tube of agar:* this is to be incubated at the body 
temperature. 
The microscopical examination is made in the manner 
described for pus, a simple stain and also Gram’s stain 
being used. The presence of streptococci, staphylo- 
cocci, and pneumococci will be revealed; bacilli may 
be present, and in this case it should not be forgotten 
that the tubercle bacillus stains by Gram’s method. If 
no organisms are found in these films, or if there are 
organisms which resemble the tubercle bacillus in 
general appearance, another specimen should be sub- 
mitted to prolonged staining in hot carbol-fuchsin and 
decolorisation in dilute sulphuric acid, and thoroughly 
searched for the tubercle bacillus. If the result is 
negative several other films should be searched. 
The cultures are to be examined after twenty-four 
hours’ incubation. The pneumococcus will produce 
tiny colourless colonies on the surface of the agar; the 
streptococcus forms similar small colourless colonies, 
but these are distinctly more opaque in the centre; 
* The practitioner is recommended to inoculate the culture 
directly from the hypodermic needle. The cotton-wool plug is to 
be withdrawn somewhat and the projecting end thoroughly singed 
in the flame: the needle (still attached to the syringe) is then pushed 
through the plug, and a drop or two of the fluid expelled directly on 
to the surface of the medium. A similar device may be employed 
where the fluid is collected in a pipette. 
