ætiology of spasmophilia is still a matter for dispute, but the
evidence which we possess is in favour of the view that we have here
to deal with a disturbance of calcium metabolism. The calcium content
both of the blood and of the central nervous system has been shown to
be much lowered. It is in keeping with this that clinically we note
how frequently spasmophilia and rickets occur in the same child. In
some families the condition recurs through many generations.

For our present purpose--the examination of some common neuroses of
nursery life--it would be out of place to enter into a detailed
consideration of this disorder of spasmophilia as a whole. The symptom
of laryngismus stridulus--the so-called breath-holding--alone need
concern us, and that for a special reason. The spasm of the glottis is
produced under the influence of any strong emotion--in anger, for
example, or in fear, in excitement or in crying for any reason. To
control or prevent it we must direct attention not only to the
condition of spasmophilia, but also to the management of the children
who are always excitable and emotional. In these children every burst
of crying, however produced, whether by a fall, by a fright, by the
entrance of a stranger, or by a visit to a doctor, is apt to be
ushered in by a long period of apnoea, due to spasm of the glottis
and of the diaphragm. The first few expirations are not followed by
any inspiration. For several seconds the silence may be complete,
while the child steadily becomes more and more cyanosed, or the body
may be shaken by incomplete expiratory movements and strangled cries
which are suppressed because the chest is already in a position of
almost complete expiration. In the worst cases, when the apnoea
lasts a very long time, there may be convulsive twitching of the
muscles of the face, or the attack may even terminate in general
convulsions. Very occasionally the spasm is actually fatal. In all