The exciting causes of spasm of the glottis are not well defined. In a few cases we are able to definitely fix upon something as the occasion of the attack. It is possible that there may be some central lesion, and this may be well defined. This is rare, however. It is nevertheless true that the onset is generally preceded by some derangement of the general health. There has been for a day, or perhaps only for an hour or two, a slight cold, a little hyperæmia of the respiratory mucous surfaces, or disturbances of the digestive tract, or the child has been unusually fatigued or excited from play or study. The secretions have in other cases been deranged. No one of these causes has perhaps been of sufficient gravity to attract the attention of the mother or nurse. The indisposition, if it has been noticed at all, has been regarded as only one of the many ephemeral troubles that so often occur in infancy, and no anxiety has been felt. Of all these possible causes, the one most frequently invoked after the attack is a cold, slight, it is true, but nevertheless, in the light of the subsequent history, evidently a mild form of inflammation of the laryngeal mucous membranes. SYMPTOMS.--Spasm of the glottis usually takes place at night. It is true that some authorities deny that this is the case. Stefen says "that it is quite as likely to occur during the day as night." In a great majority of instances, however, it will be found that the attack occurs after the child has been asleep. During the day there has been perhaps a slight disturbance of the general health, a little inclination to cough, or there has been a catarrh of the fauces or bronchial mucous surfaces; nothing, however, of a serious character has been observed. At midnight or later the little one awakes with a crowing or {71} whistling inspiration. It starts up in bed, and evidently experiences great difficulty in breathing; this difficulty is manifestly in inspiration; expiration is easy and free. The eyes are prominent, the lips blue, the surface often bathed in perspiration; pulse frequent, small, at times irregular; there is, if the child be old enough to reason in the matter, great alarm; there is often cough, and this cough is characteristic: it is a hoarse, metallic, barking, peculiar cough, described as croupy. If the spasm is limited to the larynx, the other muscles not being affected, the patient clutches at whatever it can reach, and often seizes the throat as though there was something there to tear away. The general surface becomes cyanotic and all the symptoms of asphyxia are present. The voice, though not generally extinct, is altered; it becomes hoarse, or husky, as it is called; in a few minutes the severity of the attack is passed, and the little sufferer sinks exhausted into a sleep more or less disturbed. A second attack may occur the same night, or there may be nothing more to alarm the attendants till the next night. The second attack, if it