e is no blocking of the passages
at the fourth ventricle, the foramina being as a rule much larger than
normal, no form of drainage is beneficial. Ligation of the common
carotids, one some weeks after the other, has been successful in
restoring the balance which normally exists between the secretion and
absorption of the cerebro-spinal fluid (H. J. Stiles). In acquired
hydrocephalus, puncture of the ventricles is sometimes followed by a
remarkable improvement in the symptoms, and may even result in
apparent cure. An exploring needle is introduced at the lateral angle
of the anterior fontanelle, to avoid the superior sagittal
(longitudinal) sinus, and from a half to one ounce of cerebro-spinal
fluid withdrawn. This is repeated once a week for several weeks.
Continuous drainage of the fourth ventricle through an opening made in
the occipital region (Parkin), and the establishment of a
communication between the ventricle and sub-arachnoid space
(Watson-Cheyne), or between the sub-arachnoid space of the spinal cord
and the peritoneal cavity, or the retro-peritoneal space (Cushing),
have been tried, with little more than temporary benefit in the
majority of cases. Operative treatment, if it is to do good, must be
undertaken early, before permanent changes in the brain have taken
place.

#Micrencephaly.#--This condition is due to defective development of
the brain, and not to premature closure of the cranial sutures and
fontanelles, and as the subjects of it are mentally deficient, and
often blind, deaf and dumb, the removal of segments of the skull with
a view to enable the brain to develop have proved futile.

CEREBRAL TUMOURS

As a comparatively small proportion of tumours of the brain--using the
term "tumour" in its widest sense--are amenable to surgical treatment,
it is only necessary here to refer to those aspects of this subject
that have a distinctively surgical bearing.

Various forms of growth occur in the brain, the most common being
tuberculous nodules, syphilitic gumma, endothelioma, glioma, and
sarcoma. Less frequently fibroma, osteoma, and parasitic, haemorrhagic,
and other cysts are met with. The growth may originate in the brain
tissue primarily, or may spread thence from the membranes, or from the
skull. In relation to operative treatment, it is an unfortunate fact
that those forms that are well defined and do not tend to infiltrate
the brain tissue, usually occur at the base, where they are difficult