side
of the body. The cranial nerve-trunks also are liable to be pressed
upon.

Tumours and cysts _in the cerebellum_ give rise to symptoms similar to
those of cerebellar abscess (p. 381).

Tumours _in the cerebello-pontine angle_, in addition to the special
symptoms associated with cerebellar lesions, give rise to symptoms of
interference with nerve-roots of the same side. The facial and
acoustic nerves are most frequently affected, resulting in facial
weakness, tinnitus, loss of perception for high-pitched notes, as
tested by Galton's whistle, or absolute unilateral deafness. Any of
the other cranial nerves from the fifth to the twelfth may be either
irritated or paralysed. Pressure on the pons may produce hemiplegia of
the opposite side, with spasticity and exaggeration of reflexes.
Sudden death may occur from crowding of the cerebellum into the
foramen magnum.

With the growth of the tumour the symptoms become aggravated, the
optic neuritis is followed by optic atrophy and blindness, the patient
gradually becomes stuporous, and finally dies in a state of coma. The
severity of the symptoms depends to a large extent on the rapidity of
growth of the tumour; thus an osteoma growing slowly from the inner
table of the skull and implicating the brain may reach a considerable
size without producing cerebral symptoms, while a comparatively small
sarcoma or syphilitic gumma of rapid growth may endanger life. A
sudden and serious aggravation of symptoms may result from haemorrhage
into a soft tumour, such as glioma.

The _diagnosis_ of the pathological nature of a cerebral tumour is
generally "hardly more than a guess" (Gowers). At the same time it may
be borne in mind that _syphilitic gummata_ occur in adults, from forty
to sixty years of age, who have suffered from acquired syphilis, and
who may present other evidence of the disease. They tend to increase
somewhat rapidly. A negative Wassermann reaction does not necessarily
exclude a diagnosis of brain syphilis. Severe nocturnal pain which
interferes with sleep is often a prominent symptom. Gummata are
generally situated on the surface of the brain; they often originate
in the dura mater, and when exposed are easily enucleated. Improvement
in the symptoms may follow the administration of iodides and mercury,
or organic arsenical salts of the salvarsan group, but in many cases
the growth is very resistant to anti-syphilitic treatment.

_Tuberculous masses_ occur most