I dwell on this subject the more because there is in a fit of _convulsions_ something so intensely painful to behold that it is easy to exaggerate its danger, and to lose all presence of mind in panic. First, then, it is well to bear in mind that real disease of the brain rarely, very rarely, I do not say never, begins with convulsions; and next, that their real danger is in general in exactly opposite relation to the frequency of their occurrence. Convulsions now and then return thirty, forty, or more times in twenty-four hours, and continue to do so sometimes for three or four days together. They are, indeed, not without peril, for the perpetually returning disturbance of the circulation may give rise to an overfilling of the vessels of the brain, or to a stagnation of the blood within them, or the spasm may affect the muscles which open and close the entrance to the windpipe, and the child may die choked as in a paroxysm of whooping cough, or in a fit of spasmodic croup, or lastly the violent and frequently repeated muscular movements may at length exhaust its feeble frame. But still, such frequently recurring convulsions are in themselves no evidence that the brain is diseased; they do but show that the irritability of the spinal cord is increased to a degree which the brain is no longer able to control, and which therefore manifests itself in violent convulsive movements. It is thus that the poison of scarlet fever or of small-pox sometimes displays its influence over the whole system by producing violent convulsions at the outset of those diseases; thus that they follow on some indigestible article of food, or that the mother, over-heated by violent exertion, or overwhelmed by the news of some unexpected calamity, sees her babe, to whom she is in the act of giving the breast, suddenly seized by a violent convulsion.