sensitive, excitable, and nervous, and that every one is agreed that
the nervous system is intimately concerned in its causation.

A close association between cyclic vomiting in children and that form
of periodic headache known as migraine has often been observed. It is
sometimes found that one or both parents of a child with cyclic
vomiting suffer habitually from migraine. In a few instances the one
condition has been observed to be gradually replaced by the other, the
child with cyclic vomiting becoming in adult life a sufferer from
migraine. There is indeed much which is common to the two conditions.
The periodic nature of the seizure, often following a time when the
general health and vigour appear to have been at their optimum, the
extreme prostration, and the comparatively sudden recovery are found
in both. In the cyclic vomiting of children, it is true, little
complaint is made of headache, the visual aura is absent, and the
vomiting is invariably the most prominent symptom.

Cyclic vomiting seldom occurs before the fourth year. It is
characterised by sudden profuse and persistent vomiting and by very
great prostration. All food, it may be even water, is promptly
rejected. The vomited matter is generally stained with bile;
occasionally the violence of the vomiting causes hæmatemesis. In many
cases the temperature is raised; sometimes it may be as high as 103°
F. The duration of an attack varies. In most cases it does not last
longer than forty-eight hours. On the other hand, attacks lasting as
long as a week are by no means unknown. Within a short time of the
onset the urine may be found to contain acetone bodies, the breath may
smell distinctly of acetone, and the child may become torpid and
drowsy or agitated and restless. At times there may be exaggerated and
deepened respiratory movements--the so-called air hunger. In many