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TUBERCULOSIS.                          239

Upon culture-media a distinct rapidity of growth is
observable, and we find that, instead of growing only
where glycerin is present, the Bacillus tuberculosis galli-
iiarum will grow upon blood-serum, agar-agar, and bouil-
lon as ordinarily prepared. It will not grow upon potato.
The bacillus will grow at 42-43° C. quite as well as at
37° C., while the growth of the tubercle bacillus ceases
at 42° C. Moreover, the temperature of 43° C. does not
attenuate its virulence. The thermal death-point is 70°
C. Upon culture-media it can retain its virulence for
two years.

The growth upon artificial culture-media is luxuriant,
and lacks the dry quality characteristic of ordinary
tubercle-bacillus cultures. As it becomes old a culture
of fowl-tuberculosis turns slightly yellow.

Birds are the most susceptible animals for experimental
inoculation, the embryos and young more so than the
adults ; guinea-pigs are quite immune. Artificial inocu-
lation can only be made in the subcutaneous tissue, never
through the intestine. The chief seat of the disease is
the liver, where cellular nodes, lacking the central coag-
ulation and the giant-cells of mammalian tuberculosis,
and enormously rich in bacilli, are found. The disease
never begins in the lungs, and the fowls which are dis-
eased never show bacilli in the sputum or the dung.

Rabbits are easily infected, an abscess forming at the
seat of inoculation, and later nodules forming in the
lung, so that the distribution is quite different from that
seen in birds.

The bacillus stains like the tubercle bacillus, but takes
the stain rather more easily. The resistance to acids is
about the same.

Pseudo-tuberculosis.—Eberth, Chantemesse, Charrin,
and Roger have reported certain cases of so-called pseudo-
tuberculosis. The disease occurred spontaneously in
guinea-pigs, and was characterized by the formation of
cellular nodules in the liver and kidneys much resembling
miliary tubercles. Cultures made from them showed the