SANITARY RELATIONS OF THE SOIL. 473 



high degree were reached at any place on the premises, as, for example, 

 in a cesspool, that concentration would cease and a favorable degree 

 of dilution would take its place, somewhere in the neighborhood, at a 

 greater or less distance from the focus of filth. We should therefore 

 always insist upon the degree of cleanliness which we understand to 

 promote the greatest possible prevention and dilution of filth, as our 

 hygienic aim ; and we shall furthermore do well, if we remove not 

 only from our houses, but from the neighborhood, and keep removed, 

 all that seems to us to be dirt, and offends our innate aesthetic feelings. 



The mycologists have further taught us that no germs escape from 

 fluids and moist objects by mere evaporation, but that they only pass 

 into the air in the form of dust, or when gases are generated and puff 

 out, or when something adheres to things that are washed with such 

 moist objects. We might be tempted to conclude from this that noth- 

 ing more is necessary, to make and keep our abodes free from disease, 

 than to keep everything propei'ly moist. But, aside from the fact that 

 damp houses and damp soils are positively disadvantageous to health, 

 it would not be possible to maintain such a degree of moisture or other 

 conditions that it should never be too dry, that there should never be 

 any spurts of gas, and that no germs should ever be washed off. We 

 can judge of the uselessness of such efforts from the fact that no one 

 has ever found air, either out-of-doors when it has rained incessantly 

 for a long time, nor in a house where it is still moist, that was free 

 from mold. We attach more importance to the fact, likewise estab- 

 lished by mycologists, that all germs flourish only in fluids and damp 

 media, and that moist walls, not dry ones, become moldy. 



If moisture really afforded protection against the escape of germs, 

 we mio-ht imagine the drains and sink-holes connected with our houses 

 to furnish the best kind of drainage, because they are always moist, and 

 contribute something to the required moisture in the soil. I consider 

 these sinks close to the house to be dangerous neighbors, even when 

 they are designed only to carry off rain-water. I proceed upon the 

 time-honored experience of physicians that certain malarious diseases 

 prevail most actively in damp spots in houses and villages situated in 

 hollow places or at the foot of slopes, after inundations. A sink is an 

 artificial trough, an artificial flood-region for each house, into which is 

 concentrated the drainage from the roof and from the surrounding 

 ground. By it a certain part of the house-ground is exposed to occa- 

 sional floods, which can have no other results for the house than the 

 occasional inundations in a larger region have for the places lying 

 within it. When such pits are unavoidable, it is well to have them as 

 far as possible from the house ; but it would be better to conduct the 

 water coming from the roof or elsewhere to some place where it can 

 no longer prejudice our health. I look upon the removal or great 

 diminution of these sinks as constituting the chief advantage of the 

 sewerage of cities. The hygienic value of sewerage may have been 



