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varied sub-acute pulmonary infiltrations of similar aetiology, is
significant, although is some cases debatable, and I think quite
a number of these cases are probably streptococcal in origin.
One such case resembling miliary tuberculosis has recently been
under our care, but has responded admirably to treatment.
Bacteriological diagnosis in pulmonary tuberculosis.
The most reliable single piece of evidence of active tuberculous
disease is provided by the demonstration of tubercle
bacilli in the sputum. For obvious active cases the simplest
methods of examination are required from the laboratory point of
view; in other words, a person with established pulmonar}
tuberculosis in an active state discharges tubercle bacilli in such
numbers that they are easily demonstrated by the microscope in
direct films made from sputum selected at random.
Certain patients, however, come under observation in the
early stages of the disease with suspicious histories, and possible
clinical and X-ray abnormalities. Very often in these cases no
genuine specimen of sputum is produced and the ordinary
routine method of examination will fail to reveal tubercle bacilli.
The bacteriological diagnosis in such cases may only be revealed
after repeated examinations, using varying techniques. This
bacteriological diagnosis may be of decisive importance, and
hence, other methods than the routine simple method of direct
microscopic examination may be required. Such methods are:—
(a) The anti-formin concentration method, which we
invariably use where the direct method has failed to
reveal bacilli,
(b) Examination of the sputum by artificial culture.
The isolation of tubercle bacilli in pure culture from the
sputum has developed remarkably since this method
was first introduced. Special equipment for the preparation
of these culture media is necessary, and where
the anti-formin method in a suspected case is negative,
we invariably send the sputum to the pathological
laboratory to be examined bv the culture method.
(c) Animal Inoculation Method.
Inoculation of a guinea pig is the most sensitive method
of detecting the tubercle bacillus, and this method may
require to be employed in certain selected cases, and it