degeneration and necrosis of the granulation tissue results in the
breaking down and destruction of the tissue in which it is formed.
Another group is that in which chronic inflammation is due to mild or
attenuated forms of pyogenic infection affecting especially the lymph
glands and the bone marrow. In the glands of the groin, for example,
associated with various forms of irritation about the external genitals,
different types of _chronic lymphadenitis_ are met with; they do not
frankly suppurate as do the acute types, but are attended with a
hyperplasia of the tissue elements which results in enlargement of the
affected glands of a persistent, and sometimes of a relapsing character.
Similar varieties of _osteomyelitis_ are met with that do not, like the
acute forms, go on to suppuration or to death of bone, but result in
thickening of the bone affected, both on the surface and in the
interior, resulting in obliteration of the medullary canal.

A third group of chronic inflammations are those that begin as an acute
pyogenic inflammation, which, instead of resolving completely, persists
in a chronic form. It does so apparently because there is some factor
aiding the organisms and handicapping the tissues, such as the presence
of a foreign body, a piece of glass or metal, or a piece of dead bone;
in these circumstances the inflammation persists in a chronic form,
attended with the formation of fibrous tissue, and, in the case of bone,
with the formation of new bone in excess. It will be evident that in
this group, chronic inflammation and repair are practically
interchangeable terms.

There are other groups of chronic inflammation, the origin of which
continues to be the subject of controversy. Reference is here made to
the chronic inflammations of the synovial membrane of joints, of tendon
sheaths and of bursæ--_chronic synovitis_, _teno-synovitis_ and