Constituents of Thames Mud. By Lionel 8. Beale. 17 



in which it is to be practically dealt with is decided. I have often 

 wondered whether, besides the Thames, there is another river in the 

 world, on the mud-banks of which could be found in equal quantity, 

 particles of faecal matter, fragments of muscular fibre in every stage 

 of disintegration, fibres of yellow elastic tissue, spiral fibres from 

 vegetables, and many other constituents of food which have passed 

 through the human intestinal canal, with other organic matters in a 

 state of decomposition, discharged as sewage, to undergo disin- 

 tegration in the river, and there become resolved at last into harmless 

 matter. 



It is said with truth that London is the healthiest city in the 

 world, but the possibility that our river may any summer seriously 

 damage our reputation must not be lost sight of : year by year 

 the proportion of sewage to the water increases, and the particular 

 point at which the sewage contamination becomes dangerous to 

 health is unknown, for there is no experience to guide us, while so 

 many circumstances contribute to the maintenance of its present 

 harmless condition on the one hand, and such comparatively slight 

 departures from the ordinary conditions might cause disaster on the 

 other, that the problem is one of the most complex and difficult 

 that could be presented for solution ; while it is doubtful whether 

 the precise changes that would endanger the public health could be 

 discovered by experiment and determined beforehand. In fact there 

 is much uncertainty, though little ground for satisfaction. 



Granting for a moment the correctness of all that has been said 

 in favour of the state of the river at this time, granting that at 

 present the sewage is carried away, there remains the important 

 question whether without very considerable changes the removal of 

 the sewage in the course of a few years will be as efficiently 

 carried out as it is now. The amount of sewage is constantly in- 

 creasing, the amount of water by which it is diluted remains the 

 same. Must not the time come when the proportion of sewage to 

 the water becomes so large that its disintegration and harmless 

 decomposition within the proper time will be impossible ? 



As long as the sewage is passed into and immediately mixed 

 with a very large volume of water, our drainage system is no doubt 

 very effective, possibly as near perfection as can be expected in 

 a case where the removal of the sewage of a population of four 

 millions has to be provided for. During the greater part of the 

 year the sewage is no doubt sufficiently diluted as it passes along the 

 sewers, while these are well scoured by the flow through them ; but 

 when little rain-water is added to the water supplied by the com- 

 panies, what will be the state of the sewage ? So far, therefore, from 

 the surface rain-water being diverted and prevented from passing 

 into the sewers, every arrangement ought to be made to facilitate 

 its flow into and exit from them. 



Ser. 2.— Vol. IV. 



