As a postoperative precaution, all materials which can be destroyed after use in a septic case should be burned. If this be not practicable, they should be soaked for twenty-four hours in a strong solution of corrosive sublimate, say 1 to 500. At the conclusion of operation there should be no opportunity left for dissemination of infection.
Sponges.
—In place of sponges, gauze or absorbent cotton wrapped in gauze are now generally in use, prepared as above. There are some purposes for which sea-sponges are very convenient if they can be made reliable. Those which are received fresh from the dealer should be freed from sand by beating in a mortar, placed in a solution of 1 to 500 of potassium permanganate, and then transferred to a solution of sodium sulphite containing 5 per cent. by volume of pure hydrochloric acid; in this they remain until they are bleached out, which will take but a few minutes. They are then thoroughly washed in sterile water and stored in 5 per cent. carbolic solution.
Suture Materials, etc.
—Wire, silkworm-gut, horse-hair, and silk or linen thread may be sterilized, if not rolled too tightly, by twice boiling for a half-hour, and then being allowed to dry, or preserved in 5 per cent. carbolic solution or in sterile alcohol. Disappointment often comes from rolling these materials so tightly upon spools that sterilization of the deeper layers is not complete. This is true of catgut as well as of the other animal sutures.
Catgut.
—Catgut, so called, is usually made from the intestine of the sheep, and must be freed from anthrax germs or spores. It should be rolled loosely on spools or rods, each layer separated from that beneath by a piece of gauze. The writer prefers to free it from animal fat by a preliminary soaking in ether or benzene. After this it may be sterilized by boiling in alcohol, preferably absolute, which must be in a container not tightly closed. This is placed in water, raised gradually to boiling, and should boil for two hours. This process should be repeated at least once after the expiration of twenty-four hours. This is the simplest of all procedures and generally proves reliable. Other methods are those of exposure, for instance, to cumol, a volatile paraffin oil, in which it is boiled under pressure in a special apparatus, the temperature being raised considerably above the boiling point of water (300° F.). When the receptacle is opened the cumol is drawn off or evaporates and the catgut is left dry and sterile. It should be either kept dry in a sterile jar or in alcohol. Some prefer to add to the latter a small amount of oil of juniper, which has a little hardening effect upon the animal material.
Catgut should be tested repeatedly to be assured of its sterility. Special methods of preparing catgut are as follows:
Formalin Gut
is prepared by placing the gut, wound as mentioned, in a 3 per cent. formalin solution for three hours. If the sterility of that which is used be not assured, then this preparation should be boiled in water for fifteen minutes. Catgut of large size should be immersed in a solution stronger than the above. It will probably be sufficient to give this a final boiling at the time of operation. This is almost as lasting as chromicized gut.