“Gum Boils” or “Canker Sores”

So-called “gum boils” or “canker sores” are little ulcer-like sores which at times appear in children’s mouths, caused by disarrangement of the stomach. Local applications, such as borax or powdered alum, shrink the sores and give a little relief; but the child should be given a dose of calcined magnesia at night or citrate of magnesia in the morning. (Never give a small dose of citrate of magnesia; a child of twelve years should take a tumblerful.)

Source: The Mary Frances First Aid Book, Jane Eayre Fryer