As the condition becomes more serious, a slight crowing sound is heard each time the child draws its breath, the fits of difficult breathing are much more severe; they last longer, and sometimes end in general convulsions. The breathing now does not return at once to its natural frequency, but continues hurried for a few minutes after the occurrence of each fit of difficult breathing, and is sometimes attended with a little wheezing. The slightest cause is now sufficient to bring on an attack; it may be produced by a current of air, by a sudden change of temperature, by slight pressure on the windpipe, by the act of swallowing, or by momentary excitement. The state of sleep seems particularly favourable to its occurrence, and the short fitful dozes are interrupted by the return of impending suffocation, in one paroxysm of which longer and severer than the others the infant may fall back dead. It scarcely need be said that the great majority of cases have no such sad ending as I have described, but still, whenever this spasm exists, even in a slight degree, there is always the possibility, never to be forgotten, of a sudden catastrophe. Usually, after some tooth has been cut which caused special irritation, or as disorder of the bowels has been set right, the symptoms abate by degrees, and then cease altogether, though liable to be reproduced by the same causes as those to which they were originally due. The seeking out and removing the exciting causes must be the care of the medical man, but there are some special precautions which come within the mother's own province to observe. First of all, as sudden excitement, and especially a fit of crying, are likely to bring on the attack, and since there is a possibility that any attack may prove fatal, the greatest care must be taken in the management of the child to avoid all unnecessary occasion of annoyance or of distress. Although the benefit that accrues from fresh air, or from a change of air, is often very great, yet it is very important that the child should not be exposed to the cold or wind, for I have seen such exposure followed by a severe attack of difficult breathing, or by the occurrence of general convulsions. Another reason for caution in this respect is that the occurrence of catarrh is almost sure to be followed by an aggravation of the spasmodic affection, which, though previously slight, may thereby be rendered serious or even dangerous.