THE PRACTICE OF DISINFECTION 155 



with a perforated tray or wire basket, supplied with 

 handles, to enable one to lift the steriHzed instruments, 

 etc., out of the boiling water. The addition of 2 per 

 cent, of ordinary washing soda to the water increases its 

 disinfecting action, and at the same time prevents in a 

 measure the rusting of metal instruments. 



This method of sterilization is particularly well 

 suited for soiled hnens, for dishes, trays, pans, etc., 

 that have come in contact with infectious material, for 

 glass and metal instruments, such as catheters, irriga- 

 tion tubes, forceps, etc. It is not so well suited for the 

 sterilization of knives and scissors, since it spoils their 

 keen cutting edge. For this reason some surgeons pre- 

 fer to have these instruments kept in pure carbohc acid 

 and transferred to sterile water before the operation. 

 Catheters are to advantage boiled in water to which 

 have been added 2 teaspoonfuls of liquid vaselin. This 

 forms a thin, even coating of a sterile lubricant over the 

 entire surface. Soiled linen should not at once be put 

 into boiling water, since this fixes any stains; it may be 

 put to soak for a few hours in cold water containing a 

 pound of green soap in 25 gallons, and then may be 

 heated in this to 70° or 80° C. These suds are then 

 allowed to run off and are replaced by fresh, in which 

 the linen is boiled fifteen to twenty minutes. 



Steam. — A second method of using moist heat is in 

 the form of live steam in a steam sterilizer, of which the 

 Arnold sterilizer, already described, is a good example. 

 This type of sterilizer is extensively used in bacteriologic 

 laboratories for the sterilization of culture-media, and 

 in hospitals for sterilizing dressings, mbber gloves, etc. 

 Heating to 212° F. (100° C.) for an hour is enough to 



