159 



1889-90.] NATURAL HISTORY OF GROUND WATERS. 



this gas has a specific influence in preventing the increase of microbes was 

 proven from the fact that if replaced by a current of hydrogen there 

 occurred a rapid increase in the number of microbes. 



Whether or not, however, anaerobies or microbes which multiply in 

 the absence of oxygen, can multiply in these deeper layers, experiment 

 IS as yet lacking to determine. Certain it is that these waters flowino- in 

 the tertiary zone or stratum of supersaturation with a slow uniform 

 movement depending upon their depth, the weight of water and dip of 

 theunderlying impervious bed, end by arriving at the surface as springs 

 or in wells (either dug or driven) in a sterile condition. Arrived here' 

 the water comes in contact with air, sometimes with light, also with 

 infected soils as of the mould of the surface or the organic matter which 

 finds Its way into wells, and, the conditions of sterility having disappeared 

 It becomes again inoculated with microbes. 



As may be readily understood, the farther from such underground 

 conditions a water proceeds the greater are the possibilities of its inocu- 

 lation and of the variety as well as the number of the microbes in it 

 As natural waters in different regions vary in temperature and in the 

 amount and character of the organic and mineral constituents in 



. ""I'W T^' """'"'"^ '^'^' ^'^''■""^ ^P^^^^^ °f these microscopic plants 

 should be characteristic of different waters. Winogradsky has studied 

 the species of sulphur water, while Fazio and others have found species 

 peculiar to the waters of Naples, Castellamare, etc. 



How extended are these differences of species and what the peculiar 

 influences favorable to each, has not yet been investigated. Indeed it 

 may be said that this study of species is little more than begun When 

 classification has become possible, the still more difficult matter of decid- 

 mg which are pathogenic and which are innocuous will yet remain. 



Work with a view to determining under what circumstances these 

 sterile underground waters can be obtained pure for drinking purposes 

 has recently been carried on by Carl Fraenkel of Berlin, and some inter- 

 esting results have been obtained. I shall take the liberty of introducing 

 here a condensed abstract of his experiments, as they are found to be 

 wholly in accord with the views, which reasoning, based upon the physical 

 characters of underground waters in relation to geological conditions and 

 to the known facts regarding bacterial life, has led us to deduce. 



Fraenkel's investigations were undertaken to determine if it were pos- 

 sible at all to remove with complete success infective material which had 

 once gotten into a well. 



