to professional character for a physician to hold a patent for any surgical instrument or medicine." Much the same feeling exists with regard to patenting or otherwise attempting to obtain exclusive control of means for preventing disease, for supplying fresh air or pure water, for disinfection, or for the removal of the foul and dangerous substances necessarily produced by human beings in daily life; and, while the physician, the architect, or the engineer may make use of patent ventilators, filters, traps, or closets, purchasing them as manufactured articles, because they will serve the purpose, and it is easier and cheaper to buy them than to make original designs, yet they avoid giving certificates or recommendations in favor of any such patented article, and distrust those who do so. I state this as a fact, without discussing the question as to whether it is right or wrong, wise or unwise; it is given merely as one reason why in this paper I do not discuss the merits of particular forms of patented appliances for house-drainage, since it is sufficient for my purpose to show that convenience, cleanliness, and safety can be secured without the use of any particular form or piece of apparatus. At the same time it should be distinctly understood that I do not condemn all such patents or patented articles. On the contrary, I believe that the improvements which have been made in house-drainage during the last twenty-five years have been due, to a considerable extent, to the competition of business interests, urged on and directed by scientific investigations made by men who would themselves have never patented an appliance or engaged in its manufacture.
It is to be remembered that, when a system of house-drainage has been made satisfactory, it will not remain so unless it is properly used and looked after. Rust and grease will tend to obstruct the pipes, the tops of lead bends will corrode, cloths and rubbish will be thrown into the fixtures, fresh-air inlets will become plugged by snow or mud, the open top of the soil-pipe may be closed by accumulated ice. One of the most frequent dangers arising from want of care is that which results from leaving the apparatus unused for several weeks or months, as when the family shuts up the house for the summer and goes to some health resort. In a few weeks, sometimes in two weeks, the water in the traps so far evaporates that they are unsealed, and then follows a stream of air into the house, bearing with it micro-organisms which gradually settle in the layer of fine dust which gathers on floors, shelves, ledges over doors, gas-fixtures, etc. If, now, the family returns and occupies the house, using only the ordinary processes of sweeping, dusting, etc., which do not destroy the germs but merely scatter them about, there is serious danger of sickness. On leaving a house in this way, arrangements should be made to
