r: \CTICAL DISIXFECTION AND STERILIZATION 131 



germicidal value than steam of the same temperature. To do this, a 

 vacuum pump is attached to the piping, whereby a vacuum of fifteen 

 inches can be obtained in the chamber. The steam should be thrown 

 into the chamber in large ajnount, both above and below the goods, 

 and the excess should escape through an opening in the bottom of the 

 chamber, so as to more readily carry off with it any air still remaining. 

 The live steam in the chamber should be under a pressure of two to 

 three pounds, so as to increase its action. 



To disinfect the goods, we place them in the chamber, close tight the 

 doors, and turn the steam into the jacket. After about ten minutes, 

 when the goods have become heated, a vacuum of ten to fifteen inches 

 is produced, and then the live steam is thrown in for twenty minutes. 

 The steam is now turned off, a vacuum is again formed, and the cham- 

 ber again superheated. The goods are now thoroughly disinfected and 

 dry. In order to test the thoroughness of any disinfection, or any new 

 chamber maximum, thermometers are placed, some free in- the cham- 

 ber and others surrounded by the heaviest goods. It will be found 

 that, even under a pressure of three pounds, live steam will require ten 

 minutes to penetrate heavy goods. 



The Disinfection of Hands, Instruments, Ligatures, and Dressings 

 for Surgical Operations. 



Instruments. All instruments, except knives, after having been 

 thoroughly cleansed, are boiled for three minutes in a 1 per cent, solu- 

 tion of washing soda. Knives, after having been thoroughly cleansed, 

 are washed in sterile alcohol and wiped with sterile gauze and then put 

 into boiling soda solution for one minute. This will not injure their 

 edges to any great extent. 



Gauze. Gauze is sterilized by moist heat either in an Arnold steam 

 sterilizer for one hour or in an autoclave for thirty minutes. It is placed 

 in a perforated cylinder or wrapped in clean towels before putting in 

 the sterilizer, and only opened at the operation. 



lodoform gauze is best made by sprinkling sterile iodoform on plain 

 gauze sterilized as described above. 



Ligatures Catgut. Boil for one hour in alcohol under pressure at 

 about 97 C. It is often put in sealed glass tubes, which are boiled 

 under pressure. These remain indefinitely sterile. The alcohol does 

 not injure the catgut. If desired, the catgut can be washed in ether 

 and can be soaked a short time in bichloride before heating in alcohol. 

 Boeckman, of St. Paul, suggested wrapping the separate strands of cat- 

 gut in paraffin paper and then heating for three hours at 140 C. This 

 procedure prevents the drying out of the moisture and fat from the 

 catgut, so that it remains unshri veiled and flexible after its exposure. 

 Darling, of Boston, tested this method and found it satisfactory. Dry 

 formaldehyde gas does not penetrate sufficiently, and is not reliable. 

 Silver wire, silk, silkworm gut, rubber tubing, and catheters are boiled 

 the same as the instruments. 



