6 Transactions of the Society. 



Commission appointed to consider the question of Thames Pollution. 

 I have received permission to communicate the results to the 

 Society, and to publish them. 



The observations made by me relate chiefly to the organized 

 constituents of the sewage which can be demonstrated in the mud 

 of the Thames by microscopical examination. Many of the particles 

 found in the mud have been identified as substances which had 

 entered into the formation of human excrements. I have en- 

 deavoured to ascertain what changes some of the most important 

 of the fsBcal constituents undergo in their passage from the houses 

 along the drains into the river until their disintegration is at last 

 completed or they have been deposited and form part of the mud 

 banks of the Thames. 



The broad and important fact which is, in my judgment, fully 

 established by the investigation is this — that several constituents of 

 human faeces are present in all the specimens of mud submitted to 

 examination. The amount of these differs considerably, though no 

 adequate means have been discovered of making an accurate 

 estimate of the quantity of any one of them, or of instituting more 

 than a very rough comparison between the muds obtained from 

 dijBferent banks. 



It must be borne in mind that the river mud is continually 

 undergoing change in its character, the surface of the bank being 

 often washed away, and old matters being mixed up with the 

 elements of recent sewage ; these being deposited together in other 

 and perhaps distant banks, as determined by the varying quantity of 

 water, the rate of its flow, and a number of other circumstances. 

 Thus the mud of any given bank will vary considerably in its 

 characters at different periods of the year, and it is quite supposable 

 that a bank, which at one time would be found to consist of nearly 

 pure sand, at another might seem to be almost entirely composed, 

 at least on its surface, of the blackest and foulest organic matter 

 undergoing rapid putrefactive changes. 



It is well known that the quantity of organic matter in the 

 mud is small. If a certain portion of the mud be dried and then 

 exposed to a red heat for a time, the loss in bulk owing to the total 

 destruction of the organic matter and the dissipation of all volatile 

 substances is very shght. On the other hand it is to be remarked 

 that neither the disagreeableness nor the danger to health of 

 organic matter in a state of decomposition is dependent upon or 

 varies according to the amount present. From a quantity of certain 

 forms of organic matter so small that it would fail to turn the most 

 delicate balance, as for example a fraction from the specimen of 

 sewage taken from an outfall near Trinity Ballast Office, an odour 

 of a most detestable character might emanate and be diffused over 

 a considerable area. But it must be borne in mind that as regards 



