nd are associated with acute spreading
conditions such as phlegmonous or erysipelatous inflammations and
suppurations, lymphangitis and suppuration in lymph glands, and
inflammation of serous and synovial membranes, also with a form of
pneumonia which is prone to follow on severe operations in the mouth and
throat. Streptococci are also concerned in the production of spreading
gangrene and pyaemia.

Division takes place in one axis, so that chains of varying length are
formed (Fig. 3). It is less easily cultivated by artificial media than
the staphylococcus; it forms a whitish growth.

[Illustration: FIG. 4.--Bacillus coli communis in Urine, from a case of
Cystitis. x 1000 diam. Leishman's stain.]

_Bacillus Coli Communis._--This organism, which is a normal inhabitant
of the intestinal tract, shows a great tendency to invade any organ or
tissue whose vitality is lowered. It is causatively associated with such
conditions as peritonitis and peritoneal suppuration resulting from
strangulated hernia, appendicitis, or perforation in any part of the
alimentary canal. In cystitis, pyelitis, abscess of the kidney,
suppuration in the bile-ducts or liver, and in many other abdominal
conditions, it plays a most important part. The discharge from wounds
infected by this organism has usually a foetid, or even a faecal odour,
and often contains gases resulting from putrefaction.

It is a small rod-shaped organism with short flagellae, which render it
motile (Fig. 4). It closely resembles the typhoid bacillus, but is
distinguished from it by its behaviour in artificial culture media.

[Illustration: FIG. 5.--Fraenkel's Pneumococci in Pus from Empyema
following Pneumonia. x 100 diam. Stained with Muir's capsule stain.]

_Pneumo-bacteria._--Two forms of organism associated with
pneumonia--_Fraenkel's pneumococcus_ (one of the diplococci) (Fig. 5)
and _Friedlander's pneumo-bacillus_ (a short rod-shaped form)--are
frequently met with in inflammations of the serous and synovial
membranes, in suppuration in the liver, and in various other
inflammatory and suppurative conditions.

_Bacillus Typhosus._--This organism has been found in pure culture in
suppurative conditions of bone, of cellular tissue, and of internal
organs, especially during convalescence from typhoid fever. Like the
staphylococcus, it is capable of lying latent in the tissues for long
periods.

_Other Pyogenic Bacteria._--It is not necessary to do more than name
s