[Illustration: FIG. 203.--Syringe for cleaning drainage-tube.] All fluid should be withdrawn from the drainage-tube. The dam should be carefully cleansed by wiping with cotton wet with the solution of bichlorid of mercury. A fresh cotton plug should be inserted in the tube, and the dam should be folded and pinned over a handful of cotton. The whole should then be covered with a sterile towel. The tube should be emptied or cleaned as often as it becomes filled. It is often necessary at first to clean it every fifteen, thirty, or sixty minutes. If free bleeding is taking place, it is most quickly arrested by frequent cleaning of the tube. Unless the nurse is experienced, the operator or assistant should watch the drainage-tube for the first hour after operation, in order to direct the nurse in regard to the required frequency of cleansing. A record should be kept of the amount of fluid withdrawn. The intervals between cleansings are gradually increased until once every six or twelve hours becomes sufficient. It is not often necessary to keep the tube in the abdomen longer than two or three days. The tube should be removed when the fluid discharged becomes serous in character and small in amount--about one dram every four or five hours. Before removing the tube the flannel binder should be opened and the wound should be exposed. When the glass tube is withdrawn, it is best to replace it by a small rubber tube. This may be done by inserting the rubber tube to the bottom of the glass tube, which is then withdrawn. If we were certain that the tube-tract were aseptic, the introduction of the rubber tube would be unnecessary, and we might close the lower angle of the incision immediately by suture. This procedure, however, may be followed by fluid-accumulation and the formation of abscess in the tube-tract. It is therefore safest always to use the rubber tube. The rubber tube should be withdrawn gradually, an inch or two every day, so that the tract will close from the bottom. In order to prevent the rubber tube slipping altogether into the drainage-tract, it is advisable to insert a small safety-pin through the extra-abdominal end. The end of the rubber tube should be surrounded and covered by several layers of gauze and the abdominal pad.