(_b_) Putrid sore mouth is an aggravated stage of the above affection; it begins on the borders of the gums as inflamed patches coated with a thin layer of yellow mucus. The slightest touch of the ulcerated places causes bleeding, and the affection can be recognized at quite a distance from the mouth by the sense of smell. The disease is contagious and may be imparted from one child to another. Carious teeth are the predisposing agents; mercury or _calomel_ in repeated and large doses produces a similar effect. A very simple and efficient remedy for this affection is a saturated solution of chlorate of potassa, in the proportion of a teaspoonful to a teacupful of boiling water; with this solution wash the mouth out every two hours, and allow a little to be swallowed at the same time; children under one year of age can swallow ten drops; under two years, twenty drops; under three, thirty drops, and larger ones can take a teaspoonful. (_c_) Thrush, sprue, or soor is another type of sore mouth that falls to the lot of some children. It resembles catarrh of the mouth, but must be considered a different disease, inasmuch that it is proven to be due to a fungus growth. The disease begins with a change of color from the natural bright red, to a livid, dark red color; the entire mucous membrane of the mouth is uniformly discolored; the discoloration never occurs in spots, and the surface presents the appearance as if a thick coat of raspberry syrup had been smeared upon it. The mucous membrane becomes dry and sticky and the secretion of the mouth is acid. On inspecting the mouth the fungi can be seen, at first as small white points if only existing a few hours, but their growth is very rapid, and they soon form large white patches, which may run together and cover the entire mouth. The treatment is directed towards removing the cause in the first place; if the child has been using the sugar teat that must be discontinued, and even a milk diet should be suspended for a few days, on account of its containing sugar and cheesy matter, and instead the child should be fed with a little thickening of arrow root or wheaten flour. The mouth must be kept sweet and clean with a solution of borax applied with a small camel’s hair brush; if the disease is obstinate, dissolve the borax in creosote water obtained from a druggist, and apply this every hour or two as above.