IGO TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. I. 



He notes the two forms of wells, so called kettle wells (kesselbrunnen) 

 from which the water is obtained by bucket or pump, and the artesian 

 wells (rohrenbrunnen). These two forms are exposed to different methods 

 of infection. 



The kettle wells are exposed first to infection from above ; secondly 

 they never possess walls of such a character as to exclude infection from 

 the surrounding soil. Experienced well-diggers assure us that no kettle 

 well, even those with the best cement or asphalt walls can be depended 

 upon to remain absolutely tight. They constantly act in relation to the 

 surrounding soil as powerful drains which not only receive the ground 

 water, but also the surface water. They are protected of course to a cer- 

 tain extent from surface infection by the filtrating power of the soil. 

 Superficial layers, however, are much more loosened up (artificially and 

 naturally) than lower layers, consequently the power of filtration is not 

 so great. 



Tube or artesian wells are not exposed to such danger of infection 

 from upper openings as kettle wells. From the outside, from the 

 nature of their construction, they are completely free from dangers of 

 infection. 



Both kinds of wells may be infected, if such infection exists, from the 

 ground water. 



He reviews the subject of the germ contents of ground water, considers 

 the results as unsatisfactory and consequently in this paper takes up the 

 question anew. 



The artesian wells, which were used for the experiments, were two in 

 number, situated in the court of the Berlin Hygienic Institute, in a part 

 of the city which has been inhabited for a number of centuries, and 

 within a few hundred metres of the Spree. Both had been placed in 

 position about two years and a half previously, and had been little used. 

 At the time of investigation the wells had not been touched for several 

 months ; the ground water stood at 4'48mm, average day temp. 12 ° C. 



Water first removed contained in i ccm. 10,800 germs. This large 

 number is explained by the stagnant condition of the water. 



April loth, 1888. 



