192 Air and Water Poisoning 



increasing amount proceeding from soakage. Few of the 

 cesspits are well constructed ; indeed, it is difficult to make 

 a cess-pit watertight. Even cement is acted on by the liquid 

 contents. Nitric acid is formed during the decomposition 

 of the urine, &c., and a portion of the lime of the cement is 

 reduced to a soluble condition, leaving the rest in 

 a porous state. To so great an extent does this occur 

 that a process founded on these changes has long been em- 

 ployed for the manufacture of nitric acid. By the soakage of 

 cess-pits the soil of a large portion of the city has become 

 so saturated with sewage that although many of the final 

 results of decomposition are odourless, the characteristic 

 smell often appears directly the ground is broken. Very much 

 of the disgusting smell which pervades some of our 

 thoroughfares is traceable to this source. An illustrative 

 case has already been cited. 



The morbific character of the matters under consideration the 

 health officer has already dealt, and 1 need not therefore dwell 

 much on them. But I may remark (as the determination of 

 this point was one of the principal questions submitted to me) 

 that between the filthy practice of flushing and the more 

 refined process of filtering, there is not so much difierence 

 as has been supposed. Very little matter, and that not the 

 most noxious, is retained by the filters, as has been seen ; 

 but the discharge being so largely diluted, rarely ofiends the 

 senses, and so escapes notice ; but this very condition spreads 

 it over a wider area, and were it not that the stream is con- 

 stant and washes the matter rapidly away, it is doubtful 

 whether the evil would not be magnified. The eonstructors 

 of filters have evidently been under the impression that the 

 charcoal would act as a disinfectant, but the power of char- 

 coal to absorb gases is limited, and almost entirely ceases 

 when it is wetted. As an absorbent of sewer gases it is, in 

 the dry state, invaluable, but even then it requires frequent 

 renewal. 



In my report to the Health Committee, I ofiered the 

 following suggestive remarks : The percolation of liquid 

 sewage through the soil, and the difficulty of keeping even 

 well-built cesspits water-tight in the presence of urine have 

 already been noted. It is clear that the storing of urine 

 in the cesspit is a question fraught with annoyance as well 

 as danger. " What," it will be asked, "is to be done with 

 the liquid when we have no sewer-pipes ? " I reply that 

 its discharge into the gutters in the first instance is a far less 



