Januaet 12, 1906.] 



SCIENCE. 



57 



respective sections, by taking for my ad- 

 dress a subject that does not call for the 

 speculative thought of theoretical chem- 

 istry, but rather the careful consideration 

 of some one subject in my own field of 

 work. I have, therefore, chosen as my 

 topic 'The Sanitary Value of a Water 

 Analysis. ' 



A question of great importance to a com- 

 munity is the character of its water supply, 

 and of equal importance to the individual 

 is the purity of the water that is used in his 

 household, whether it comes from a city 

 main, or an isolated well in the country. 

 That this was not always so considered 

 hardly requires mention, for it is not a 

 great many years since disease was consid- 

 ered a direct visitation of providence. The 

 first investigation that attracted public at- 

 tention to the fact that there might be a 

 connection between the use of polluted 

 water and disease may be said to be what 

 is known in sanitary science as the 'Broad 

 Street Well Investigation.' In the epi- 

 demic of cholera in London in 1854, the 

 parish of St. James, Westminster, which 

 in previous epidemics had suffered, on the 

 whole, less than many other parts of Lon- 

 don, suffered most severely, the death rate 

 reaching two hundred in ten thousand. 

 The whole parish was not equally affected, 

 and the center of infection, or the special 

 cholera area was in the neighborhood of 

 Broad Street, and attention was drawn to 

 the fact that, though city water was sup- 

 plied to this district, a well situated on 

 Broad Street was used to a very large ex- 

 tent for household purposes. An investi- 

 gation followed and it was shown that of 

 the deaths that occurred during the first 

 week of the outbreak among persons living 

 in this neighborhood, 82 per cent, were 

 known to have used the water from this 

 well, and that houses and factories in the 

 same radius where the water from this well 



was not used seemed to be exempt from the 

 disease. 



A strong case between cause and effect 

 was thus made out, and when a subsequent 

 examination showed that there was direct 

 leakage from an open privy into this well, 

 it established as clearly as could be done 

 by circumstantial evidence that the epi- 

 demic in St. James parish in 1854 was 

 caused by polluted water. 



A further striking proof that sewage 

 polluted water may become the effective 

 vehicle of the actual poison of disease was 

 furnished through the cholera epidemic in 

 London in 1866, but the theory that water 

 is one of the most dangerous carriers of 

 infection of cholera and of typhoid fever 

 may be said to date from 1872, and to have 

 been the result of the careful investigation 

 of the typhoid fever epidemic in that year 

 in Lausen, Switzerland. To-day we recog- 

 nize as one of the best established theories 

 of sanitary science that both cholera and 

 typhoid fever are water-borne diseases, and 

 that the primary cause of the large death 

 rate from typhoid fever is due to the use 

 of polluted waters. 



The late Professor Thomas M. Drown 

 divided all waters into two classes, namely, 

 normal and polluted waters, and stated, as 

 regards normal waters, that although they 

 differ very widely in character from the 

 pure colorless mountain brook to the dark- 

 colored water from swampy ground, they 

 are all characterized by never having re- 

 ceived any contamination connected with 

 man, and although often far from pure 

 waters, differ from a polluted water in one 

 most important respect, in that they are 

 not capable of producing, as far as known, 

 any specific germ disease. 



It is true that many normal waters, on 

 account of the large amount of vegetable 

 matter they contain, are unfit for house- 

 hold use, although they may be sanitarily 

 safe waters in the sense of not being the 



