360 APPLIED BACTERIOLOGY 



The sawdust should be rubbed on the bare boards, so 

 that the bacteria may stick to it, and then swept up and 

 burned ; after this the floor should be well scrubbed with 

 hot soap and water, the ceiling limewashed, and the walls 

 repapered before the room is reinhabited. 



Where it is not allowable to strip the wall-paper, the use 

 of a disinfectant spray as described below is indicated. 



Disinfection by Sulphur. — The burning of sulphur in 

 rooms is probably entirely without effect, unless everything 

 has first been made thoroughly damp by boiling away a 

 quantity of water in an open vessel, and the same is pro- 

 bably true of chlorine. Both of these procedures cause 

 injury to metal-work, and hence we give preference to the 

 method indicated above, which would certainly be far 

 more effective as regards destroying the vitality of the 

 greater number of bacteria. 



Those who advocate the use of burning sulphur for the 

 disinfection of a room consider that 1 pound of sulphur 

 should be burned for every 1,000 cubic feet of space ; this 

 will produce a little over 1 per cent, of sulphurous acid 

 gas in the air. Instead of burning sulphur, liquid sul- 

 phurous acid may now be bought. It is sold compressed 

 in tins, with a small metal pipe that can be cut off with a 

 knife, thus allowing the gas to vaporize slowly. 



Disinfection by Chlorine. — According to Koch, very large 

 quantities of chlorine are required to be effective, as much 

 as 15 pounds of bleaching-powder being necessary for 

 1,000 cubic feet, while to liberate the chlorine from this we 

 should need either 22 pounds of hydrochloric acid or 

 7 pounds of sulphuric acid. The sprinkling or spraying of 

 infected rooms with germicidal solutions is more frequent 

 abroad, and is a more scientific method to employ than the 

 liberation of gases, as we are not dealing with an unknown 

 virus any longer in the case of most diseases, but with 



