On examination of the insurance reports upon this question, we find that 96 per cent of all the fires originate inside of the houses. The most important cause of these fires is defective chimney construction. Bad fireplace design, careless flue construction, and poor masonry work in the chimney are responsible for many a tragic fire and a total loss of furniture, clothes, and household goods of well-meaning citizens. It is true that this is a cause of fire which may be prevented by building good chimneys and fireplaces, but there are other causes that are not so easily regulated, such as explosions from kerosene, short circuits in the electric iron or vacuum cleaner, careless throwing around of burned matches and cigarettes, and many other accidents which are bound to occur in spite of all precautions. When such fires start, there is only one thing to do: extinguish them in the quickest possible manner. But this cannot be done easily if the walls and the floors of the house are so built that they act as hidden passages and flues for the flames to creep insidiously throughout the building, breaking out in the most unexpected places and entrapping the unwary in dangerous positions. The way that many dwellings are constructed makes it possible for a fire to start in the cellar over the smoke-pipe from the furnace, in the dead of night, creep silently through the floors and up the interior partitions to the attic and second floor, until suddenly, bursting forth in all its fury, it has the sleeping inhabitants ensnared in a box of fire that has cut off their escape. The terrible heat has eaten away the strength of the bearing partitions, the floors collapse, the stairs are encircled with a writhing flame, and smoke and fire issue from everywhere as suddenly as though they had been spontaneously produced. There is no time to fight such a fire as this; about all that can be done is to escape in safety, and then the history of such conflagrations tells of the tragic death of many children left behind in the excitement. It is this fearful danger of the secret entrapping of fire that it is possible to eliminate from the wooden house. At least we can make this demon element come out into the open, where we can see to fight him. We can set safeguards against his passage through floors and walls, up stairs, and behind wainscots. In most cases where houses are so protected a fire can be quickly extinguished by the fire department or by a chemical fire-extinguisher kept in the house. This business of setting up fire-stops when the house is being constructed should be known. The closing of the passage between the plaster, furring strips, and masonry wall, the blocking of continuous ways through exterior stud walls and interior bearing partitions, the filling in of the hollow spaces behind wainscots, the protecting of the under side of stairs, and many other precautions can be provided for in the plans and specifications without adding much to the expense.