however,
frequently found in other connective-tissue tumours as a result of
degeneration, for example, in cartilaginous tumours and in sarcomas.
Myxomatous tissue is also a prominent constituent of the "innocent
parotid tumour." Mucous polypus of the nose, which is often described as
a myxoma, is merely a pendulous process of oedematous mucous membrane.

[Illustration: FIG. 53.--Myeloma of Shaft of Humerus, causing
pathological fracture. (Mr. J. W. Struthers' case.)

(The unusual site of the tumour is to be noted.)]

#Myeloma.#--A myeloma is composed of large multinuclear giant cells
surrounded by round and spindle cells. The cut surface of the tumour
presents a deep red or maroon colour. While occasionally met with in
tendon sheaths and bursae, and is then of an orange-yellow colour, the
myeloma occurs most frequently in the cancellous tissue at the ends of
the long bones, its favourite site being the upper end of the tibia.
Although formerly classified as a sarcoma, it is the exception for it to
present malignant features, and it can usually be extirpated by local
measures without fear of recurrence. The diagnosis, X-ray appearances,
and the method of removal are considered with the diseases of bone.
Sometimes the myeloma is met with in multiple form in the skeleton, in
association with an unusual form of protein in the urine (Bence Jones).

#Myoma.#--A myoma is composed of non-striped muscle fibres. A pure myoma
is very rare, and is met with in organs possessed of non-striped muscle,
such as the stomach, intestine, urinary bladder, and prostate. In the
uterus, which is the most common situation, these tumours contain a
considerable admixture of fibrous tissue, and are known as _fibroids_ or
_fibro-myomas_. They present on section a fasciculated appearance, which
may resemble that of a section of balls of cotton (Fig. 54). They are
encapsulated and vascular, frequently attain a large size, and may be
single or multiple. While they may occasion neither inconvenience nor
suffering, they frequently give rise to profuse haemorrhage from the
uterus, and may cause serious symptoms by pressing injuriously on the
ureters or the intestine, or by complicating pregnancy and parturition.

The #Rhabdomyoma# is an extremely rare form of tumour, met with in the
kidney, uterus, and testicle. It contains striped muscle fibres, and is
supposed to originate from a residue of muscular tissue which has become
sequestrated during devel