THE PRACTICE OF DISINFECTION 155 



further exhausted by means of an exhaust valve (D). 

 When a partial vacuum has been created (5 inches, as 

 registered by the gauge) the exhaust valve is shut off, 

 and through another valve (E) steam from the steam 

 chamber is admitted. As this steam finds a partial 

 vacuum it eagerly penetrates any pervious material 

 placed in the sterilizing chamber. Dressings and all 

 material to be sterilized are put into the apparatus as 

 soon as the heating is started, and are, therefore, gradu- 

 ally warmed; consequently, when steam is admitted, 

 it does not condense and does not wet the dressings. 

 When the dressings, etc., have been in contact with the 

 steam (the temperature of which varies according to the 

 pressure under which it is produced) for twenty to 

 thirty minutes the exhaust valve is again operated, for 

 the purpose of sucking the excess of steam out of the 

 material and leaving it very nearly dry. 



When the door of the apparatus is to be opened, the 

 vacuum must first be destroyed by admitting air into 

 the steam chamber through another valve (F), which is 

 plugged with cotton. 



The large municipal or private steam disinfecting 

 plants act on the same principle, and differ only in size 

 and details of construction. 



This method of disinfection can be used for all ordi- 

 nary cotton and woolen garments, bedding, rugs, mail 

 from infected ports, etc., but it is not suited to rubber 

 articles, furs, leather, delicate silks, or articles manu- 

 factured with glue, such as books. Experiments con- 

 ducted at the New York Quarantine Disinfecting Station 

 with self-registering thermometers have shown that 

 when a temperature of 110 F. is maintained in the dis- 



