Really acute inflammation of the brain is of so rare occurrence except as the result of accident or injury, and its symptoms are of so serious a character, even from the first, that medical advice is obviously needed at once. I shall, therefore, pass it over here, and endeavour to describe two forms of inflammation of the brain which are much more frequent, and at their commencement more likely to be overlooked. =Water on the Brain.=--One of these is the form of inflammation commonly known as _water on the brain_, a term which, though incorrect medically, has the advantage of being well understood. This, now, is not a simple disease, occurring in a previously healthy child, but it is a disease dependent on the same state of constitution as gives rise in other children to consumption, or scrofula, or disease of the mesenteric glands. It is this circumstance which renders the disease so serious, and recovery from it so extremely rare. This it is also which makes it so desirable to become acquainted with its symptoms, both that you may be alive to the approach of danger, and also not indulge in needless alarm when brain symptoms occur from other causes which have no relation whatever to those which give rise to water on the brain. The disease comparatively seldom comes on in a child who had previously seemed in perfect health; a state of vague ailing usually precedes its outbreak. The child loses flesh and strength, and the look of health, and the lustre of the eye, and the silky softness of the hair. The appetite becomes uncertain, the bowels irregular, with a tendency to constipation; there are little feverish attacks for a few hours, subsiding of their own accord. The sleep is not sound, the temper uncertain, the child tires even of its favourite toys; the brightness of the little face is changed for a strange, weird, wistful look--an unnatural earnestness; the child sits for moments gazing upward on vacancy, as though it saw, or sought something beyond.