Cold water sponging is a convenient and grateful method of moderating febrile heat of the surface, provided undoubted powers of reaction be present in the system. It is frequently ordered, therefore, to be employed in eruptive fevers, as measles, scarlet fever, smallpox, and other fevers; and also in some local inflammations, particularly of the brain. Vinegar may be added to the water under these circumstances with advantage. It should at first be used tepid or cool, but afterwards cold. As a general rule, the more dry and parched the heat of the surface, the more urgent the necessity for the application of the cold, and the more frequently and fearlessly ought it to be renewed,--every hour or half-hour not being too often. Should the child fall asleep during the process, and begin to perspire, it must be intermitted, but resumed again on a recurrence of the parching heat. Ice and iced water are most frequently employed in affections of the brain. The former is most conveniently applied in a well-cleaned pig's bladder, which should be half filled with broken fragments of the ice. The bladder prevents moisture about the clothes, and, from its smooth and pliant nature, readily accommodates itself to every part of the child's head. If iced water is used, care must be taken that the cloths are sufficiently large to cover the whole of the head, and they should be doubled to prevent their getting rapidly warm. Indeed, in applying cold locally, as in inflammation of the brain, one rule it is of the utmost importance to observe, viz. that the application of the cold shall be continuous; therefore a second set of cold cloths or bags of ice should be applied before the former has become warm. This plan, especially pursued during the night, along with judicious internal treatment, will save many children from perishing under the most insidious and fatal disease of childhood--water on the brain. If neither water of a sufficiently low temperature, nor ice, can be procured, then recourse may be had to refrigerating mixtures, of which the following is a good form:-- Common water, five pints; Vinegar, two pints; Nitre, eight ounces; Sal ammoniac, four ounces. THE WARM BATH.