KATHERINE.--We can tell you all about your complaint, for we can speak from personal experience, having been liable to the condition for many years. The disease is called "herpes labialis." It is one of a large group of affections which consist of small blisters on a red base and occur on various parts of the body. That variety of herpes which occurs on the side of the trunk is called herpes zoster or shingles. Herpes labialis is a very common complaint. It frequently recurs in those liable to it and often occurs on both sides of the mouth at once. It is very erratic and scarcely ever occupies the same site in two or more successive attacks. Of its cause we know but little. It is very common in typhoid fever and other infectious diseases, and is almost constantly present in pneumonia. In some people it occurs after every slight disturbance of digestion, after alterations of diet, or after change of residence from one place to another. It frequently recurs at regular intervals of time. Its origin is unquestionably nervous. It begins with a sharp smarting pain in a limited region of the lips or chin. The smarting increases, the place gets red, and in a few hours vesicles make their appearance. In a day or two the vesicles dry up and a scab forms which eventually drops off, leaving a red mark which persists for a week or more. It is purely superficial and never leaves a scar. To prevent this condition is by no means easy. Find out, if possible, what causes it, and then, if you can remove the cause, the condition will probably cease. During an attack, thickly dust the place over with zinc oxide and cover it with cotton wool. No drug has the slightest effect on the condition, and indeed the same may be said of every form of treatment. Like so many other nervous diseases, it runs its course uninfluenced by treatment. Often the liability to the condition disappears as if by magic and never again returns. MARGUERITA.--No, there is not any danger in threadworms. An injection of salt and water will remove them. A dose of one grain of santonin followed by a mild purge is sometimes sufficient to get rid of them. ONE IN TROUBLE.--Of course, if a person next door contracted typhoid fever from bad drains, you do stand a risk of catching the disease from the same source. Typhoid fever is not infectious in the usual sense of the term; that is, it is not caught from one person by another. Washing the soiled linen of typhoid patients may produce the disease unless the clothes have been disinfected. If the vegetables that you grow are cooked before you eat them, they will not produce typhoid, for the organism of typhoid is killed by boiling water. If the men have not yet removed the old pipes from your garden, you should certainly complain to the sanitary inspector of the district about it, and have the pipes removed at once, for they are not only unsightly but positively dangerous, both to yourself and to the whole neighbourhood.