nature of this disease would be proved, and sonic, as
Klcbs, Villemiu, and Cohnheim, were il within an acen
of the discovery, it remained for Robert Koch to succeed
in demonstrating and isolating the specific bacillus, now
so well known, and to write so accurate a description of
the organism and the lesions it produces as to render it
almost unparalleled in medical literature.
The tubercle bacillus (Fig. 59) is a rod-shaped organ-
FlfJ, c;q.—-Sivtion *»f A j'»r-tii»»nt';il tubm'lr from u row, showing the tubercle
liarilli; * 50^1 | Fr.tnkd and I'lrilin i.
ism with rounded ends and a slight curve, measuring
from i»5~\V5/* in length and from 0.2-0,5/* in breadth*
It very commonly occurs in pairs, which may be asso-
ciated end to end, but generally overlap somewhat and
are not attached to each other. It is very common to
observe a peculiar beaded appearance in organisms found
iu pus and sputum (Fig. 60), due to the contraction of
fragmented protoplasm within the resisting capsule (?).
By some these fragmentations are thought to be bacilli
in the stage of sporulation (see Fig. 61). Koch origin-
ally held this view himself, but researches have not been
able to substantiate the opinion, and at present the evi-