190 BACTERIOLOGY. 



the air and sunlight. In many cases when cleanliness 

 has been observed, surface disinfection of halls, bedding, 

 and furniture may be all that will be required. 



There is always a very slight possibility of a deeper 

 penetration of infection than that believed to have 

 occurred; it is, therefore, better to be more thorough 

 than is considered necessary rather than less. 



Sulphur dioxide without the addition of moisture has, 

 as already stated under the consideration of disinfect- 

 fants, very little germicidal value upon dry bacteria. 



Public Steam Disinfecting Chambers. 



These should be of sufficient size to receive all neces- 

 sary goods, and may be either cylindrical or rectangular 

 in shape, and are provided with steam-tight doors open- 

 ing at either end, so that the goods put in at one door 

 may be removed at the other. When large the doors 

 are handled by convenient cranes and drawn tight by 

 drop-forged steel eye-bolts swinging in and out of slots 

 in the door frames. The chambers should be able to 

 withstand a steam-pressure of at least one- half an at- 

 mosphere, and should be constructed with an inside 

 jacket, either in the form of an inner and outer shell or 

 of a coil of pipes. This jacket is filled with steam dur- 

 ing the entire operation, and is so used as to bring the 

 goods in the disinfecting chamber up to the neighbor- 

 hood of 220 F. before allowing the steam to pass 

 in. This heats the goods, so that the steam does not 

 condense on coming in contact with them. It is an 

 advantage to displace the air in the chamber before 

 throwing in the steam, as hot air has far less germicidal 

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

 a vacuum pump is attached to the piping, whereby a 



