The silk is rolled on glass spools or on cores of gauze, contained in glass tubes plugged with cotton, and is then sterilized in the steam sterilizer by fractional sterilization. It is advisable always to use, for heavy ligature, silk of a uniform size, because the operator becomes accustomed to the strength of the silk and knows just how much strain it will bear. Silkworm-gut is the best material to use for suture of the abdominal incision in case the “through-and-through” or interrupted mass-suture is employed. The silkworm-gut should be of the heaviest and the longest size. It may be sterilized by boiling with the instruments before the operation. [Illustration: FIG. 200.--Large cyst-trocar.] _Catgut_ is sometimes employed for ligature and suture. The difficulty of securing certain sterilization makes it advisable to avoid using this material within the peritoneal cavity. Sterilized silk is so certainly absorbed in all cases and is so easily employed that the writer has altogether given up the use of catgut within the peritoneum. It is useful as a buried suture for the muscle and fascia of the abdominal wall. Silk is not so certainly absorbed in this position, and if the catgut should happen to be imperfectly sterilized, no worse result than suppuration of the incision will occur. [Illustration: FIG. 201.--Reiner’s needle-holder.] Various methods of sterilizing catgut have been introduced. The writer uses the following method, which bacteriological experiments and clinical experience have shown to be good: The catgut is soaked in juniper oil for one week. The oil is then washed out with ether and the catgut is soaked in ether for forty-eight hours. The gut is then rolled on glass spools and is placed in a glass jar containing pure alcohol. The alcohol is boiled in the jar for an hour at a time on several successive days. The gut is used directly from this jar, and is always boiled in the alcohol for an hour before each operation. In this way, if a considerable amount of gut is prepared at one time, it is subjected to many boilings before it is used up. The alcohol is boiled by placing the glass jar in a vessel of hot water. The following methods of sterilizing catgut are also good: _The Claudius or Iodin Method for the Sterilization of Catgut._--Cut the catgut into the desired lengths and wind on glass slides or spools. Place in a wide-mouth jar with a glass stopper containing a solution composed of iodin and potassium iodide, each one part, and distilled water 100 parts. In making this solution the iodin and potassium iodide should first be pulverized in a mortar, the distilled water should be added, and stirred with the pestle until solution is complete. At the end of eight days the catgut is sterile and ready for use. It may be kept indefinitely in the solution without deterioration. Before using take the catgut from the jar with sterile forceps and rinse in sterile water.