orrhage could be employed as synonymous terms,
and that an individual who, in popular parlance, "had an apoplectic
stroke," had necessarily suffered from haemorrhage into his brain. A
small haemorrhage may not, however, cause an apoplectic fit, nor is an
apoplectic fit always caused by haemorrhage; it may be due to sudden
blocking of a large vessel by a clot from a distant part (embolism), or
by a sudden clotting of the blood in the vessel itself (thrombosis).
Owing to the prevailing idea in former times that cerebral haemorrhage
and apoplexy were synonymous terms, the word apoplexy was applied to
haemorrhage into other organs than the brain; thus the terms pulmonary
apoplexy, retinal apoplexy and splenic apoplexy were used.

The term "apoplexy" is now used in clinical medicine to denote that form
of coma or deep state of unconsciousness which is due to sudden
disturbance of the cerebral circulation occasioned by a local cause
within the cranial cavity, as distinct from the loss of consciousness
due to sudden failure of the heart's action (syncope) or the coma of
narcotic or alcoholic poisoning, of _status epilepticus_, of uraemia or
of head injury.

The sudden coma of sunstroke and heat-stroke might be included, although
owing to the suddenness with which a person may be struck down, the term
_heat apoplexy_ is frequently used, and, from an etymological point of
view, quite justifiably. The older writers use the term _simple
apoplexy_ for a sudden attack which could not be explained by any
visible disease. Again, _congestive apoplexy_ was applied to those cases
of coma where, at the autopsy, nothing was found to account for the coma
and death except engorgement of the vessels of the brain and its
membranes. In senile dementia and in general paralysis the brain is
shrunken and the convolutions atrophied, the increased space in the
ventricles and between the convolutions being filled up with the
cerebro-spinal fluid. In these diseases apoplectic states may arise,
terminating fatally; the excess of fluid found in such cases was
formerly thought to be the cause of the symptoms, consequently the
condition was called _serous apoplexy_. Such terms are no longer used,
owing to the better knowledge of the pathology of brain disease.

Having thus narrowed down the application of the term "apoplexy," we are
in a position to consider its chief features, and the mechanism by which
it is produced. Apoplexy may be rapidly fatal, bu