The results which may follow carelessness or incompetency of design in plumbing systems are illustrated by the condition of affairs lately discovered in a New York house where the pipes were being overhauled to make alterations for the remodeling of some plumbing which had been done within three years. It is not stated that the workmanship or material were found defective, but the arrangement, while conforming to most of the ordinary specific requirements, was so bad as to permit and produce an unsanitary condition of operation, entirely nullily the trap ventilation and effect a discharge to the sewer in an improper manner, which was never intended, and was not suspected until revealed by the alterations. The waste from the kitchen sink was trapped below the floor, and the back-air pipe also run below the floor, nearly horizontal to its riser, so that when the kitchen-sink waste became stopped by the collection of grease below its trap the discharge was forced through the back-air pipe, and at first escaped through the foot of its riser, which also vented the cellar-sink waste, and through that waste into the sewer. After a time the vertical riser also became obstructed with grease just above the cellar-sink trap, and cutting off the discharge through it backed the water up until it escaped through another higher branch from the riser that vented the trap of the laundry tubs, through which the sink water was thus compelled to flow to the soil pipe and thence to the drain. A considerable body of dirty untrapped water was thus always standing in the vent pipe, which it filled completely up to the inlet from the laundry-tubs, and the ventilation of the kitchen and cellar sinks was entirely destroyed. The use of a grease trap would have prevented the grease from obstructing the pipes, and the location of the sink vent-pipe branch above the overflow, as is carefully provided for in every case in good practice, would have made it impossible for discharge to have taken place except through the waste pipe.