INLETS FOR INFECTION. 



77 



In the course of my investigations I entered a wash-house belong- 

 ing to one group of the houses in question. I was followed in by its 

 owner, an old lady, who sought at once to satisfy my curiosity by 

 assuring me that the building was rarely used ; indeed, that the last 

 time it was used was six weeks ago, at which date she had washed 

 some linen there for a young man who had been very ill, and who 

 lived some distance away. I had before this noticed that all the cot- 

 tages were provided with sinks in their living-rooms, and that by means 

 of these sink-pipes, which were in unbroken communication with a 

 drain outside, offensive effluvia at times made their way into the dwell- 

 ings, these having been especially noticed toward evening, when the 

 houses were shut up and the fires were lighted. It at once occurred 

 to me that if the sick man referred to had suffered from enteric fever, 

 and if the drains for the several parts of the square all communicated 



Fig. 2. 



with the sewer by which the liquid refuse from the wash-house was 

 conveyed away, then a specifically contaminated sewer-air had replaced 

 the ordinary foul efiiuvia, and that in this way infection had been 

 " laid on " to the several households. I found that the young man 



