88 THE STORY OF THE BACTERIA. 



common decency, to say nothing of good 

 taste, is practised under conditions much more 

 flagrant than these. And then Providence or 

 Fate is shouldered with the responsibility 

 when the careless or ignorant persons them- 

 selves, or the innocent victims of their criminal 

 neglect, are stricken with typhoid fever. 



There is little doubt that the typhoid-fever 

 bacilli sometimes enter houses from sewer 

 pipes containing them, owing to defective 

 traps or leaks in the pipes. Sewer gas is in 

 itself a very bad thing to have pouring into 

 houses, and is capable of inducing a great 

 variety of disturbances of health, some of 

 which are very serious indeed, but sewer gas 

 alone cannot induce typhoid fever. For that 

 the bacillus itself must be present. It is prob- 

 able that when the traps are allowed to get 

 dry, as no doubt often happens in shut-up city 

 houses during the summer, currents of sewer 

 gas sweeping up through the pipes, on whose 

 walls the typhoid bacilli have collected, may 

 dislodge these, if the sides of the pipes are 

 dry, and carry the germs as floating dust 

 into the rooms, where they may settle, and 



