216 REPORT— 1876. 



are not spoiling a useful process by an unintelligible application of it — one of tlie 

 great dangers of improvement. 



The second point which I have mentioned— the facilitation of contagious or 

 infectious disease by mere proximity — is obvious enough in its generality. Its 

 details belong to Section D. 



The atmosphere is probably a much greater carrier of noxious germs than water ; 

 but, as Dr. Tyndall has judiciously remarked, the aerial germs appear to be some- 

 times in a le«s forward, and sometimes, perhaps, in a more effete, state of develop- 

 ment than those which are met with in water, or which liave once taken root upon 

 moist tissues. On the average, therefore, resistance to them is probably easier. 

 However this may be, it is clear that we camaot subject the supply of atmospheric 

 air, which is necessary for our lungs and skin, to the same complete chemical or 

 mechanical treatment as we can, and do, when necessaiy, our supply of drinking- 

 water. Any attempt at the disinfection of air of doubtful purity must necessarily 

 be of the crudest and most empirical kind. In the present state of our know- 

 ledge and resources it can hardly be of interest to the engineer. 



The third point affords a remarkable example of what I have just mentioned as 

 the greatest danger of all improvements — their unintelligent use. No one can 

 deny that the watercloset and the sewer are great mechanical improvements ; yet 

 they ha^e been great carriers of disease. As applied to the particidar problem of 

 getting rid of waste products, especially solid products, I do not think they were 

 any improvement at all on much that we already had. In many towns in Great 

 Britain, where there previously existed a well imderstood and well carried out 

 scavenging system, I thinlv they have done more in saving trouble than in con- 

 ducing to health. I think the real key to the problem of getting rid of the nuisance 

 of waste products is to be found in the old aphorism that dirt is simply mntter out 

 of place. Hence the first step is to take care that such products shall not become 

 waste; and one condition of this is, that they should not be carelessly mixed. The 

 greater part of the sewage difficulty is, I think, simply tlie result of neglecting this 

 truth. It is especially the case with London sewage. With our water supply, our 

 watercloset system in houses, our drainage of houses, factories, and streets all 

 together, we ha^e accumulated a ri\er of filth, the complex admixture and 

 enormous mass of which lia\e rendered it most difficult and dangerous to control 

 effectually. I tliink we sliall yet be driven to meet the difficulty at its source in 

 tlie way suggested — by dealing with it in detail, subdividing both fi'om house to 

 house and I'rom kind to kind, and allowing notliing but the mere washings of the 

 streets to get into our sewers at all. So far as the getting rid of waste products is 

 concerned, I belie-\e we must be content to write off the whole cost of our Metro- 

 politan Main Drainage. 



There is another undoubted improvement which the legislature has decided upon 

 applying to London, concerning which I feel no small amount of mii^givbg lest it 

 should be applied without intelligence ; and that is, the constant supply of water in 

 place of the intermittent cistern supply. Asa mere mechanical convenience it 

 will be a very great improvement ; but I foresee two dangers, one of sewage con- 

 tamination through the waterclosets, the other the waste of an article already 

 becoming scarce. The first is no idle fear. The experience of Croydon and other 

 places has shoAvn that it is possible to make the water supply and the sewage a 

 circulating system, with fever or cholera as its inevitable consequence. It has 

 been bad enough in several places of moderate size ; but in London, whether we 

 regard it with reference to the mass of contaminating material, or to the quantity 

 of human life to be affected by it, the risk has a much more serious aspect. I shall 

 be sorry to see the constant supply established in London without taking some 

 effectual seeiuity, either by the mterposition of cisterns or otherwise, to prevent 

 the possibility of back draught from the cess to the drinldng- water. Without some 

 such precaution, I think the mechanical impro%oraent may be a fatal gift. 



I have said that the problem of the crowd, if I may venture so to call that of 

 maintaining purity in the supply of a deuse population, is now presenting itself in a 

 new and very difficult form. That is so notably in the matter of water supply ; 

 because until now it has generaDy been possible, by some expenditure in aqueducts 

 and care in the selection of tlie sources, to obtain a sufficient supply of thoroughly 



