194 Profs. P. F. Frankland and Marshall Ward. 



§ II. On some Relations between the Bacteriological Contents of Water 

 and the Environment. 



Although the evidence on which the above statements are founded 

 is of unequal value in different cases, it may be regarded as estab- 

 lished that the germs of pathogenic Schizomycefces do occasionally 

 occur in waters used for domestic purposes, and the records of medical 

 literature f ally bear out this conclusion.* 



The next point for discussion is, How do these germs find their 

 way into potable waters ? 



It seems capable of proof that water, as such, does not necessarily 

 contain any bacteria at all, for if it is examined at the source of deep 

 springs, or in the deep subterranean layers tapped by artesian well- 

 pipes, it is found to be either wholly or practically free from 

 organisms at or near the source. Moreover, it is an axiom that, 

 in cases where the water-supply is drawn from rivers, there are more 

 bacteria as we go towards the mouth, and fewer as we ascend the 

 heights of the watershed ; whilst the gain in bacteria, both as 

 regards forms and numbers of individuals, is marked below each 

 town or inhabited area through which the river flows. f 



We now proceed to the questions, Why are the deep waters below 

 the sub- soil free from germs ? How do they become contaminated 



# Especially for typhoid. See Vaughan and Novy (' Med. News,' 1888, p. 92), 

 Charrin ('Ann. d'Hyg. Publique et de Med. Legale, 1887, pp. 520— 529) , Brouardel 

 efc Chantemesse (' Ann. d. Hyg. Publ. et de Med. Leg.,' 1887, No. 12), Hauser and 

 Kreglinger (' Die Typhus Epid. in Triberg in den Jahren 1884 und 1885,' Berlin, 

 1887), and the literature already quoted. 



f Eor more details in support of these statements, consult : — Burdon Sandersor 

 ('Rep. of the Med. Officer of the Privy Council,' 1870 and 1872), Angus Smith 

 ('Rep. Med. Officer Local G-ov. Board,' 1884), Eol and Dunant ('Arch, des Sc. 

 Phys. et Natur. de Greneve,' 1884 and 1885), Di Yestea and Tursini ('Recherches 

 sur les Eaux de Naples,' 1885), Cramer (' Die Wasserversorgung von Zurich,' 1885), 

 Percy F. Frankland (' Monthly Reports to the Local Government Board on the 

 Bacteriological Examination of the London "Water Supply,' 1885 — 1888 ; also 

 ' Journ. Soc. Chem. Industry,' 1885 and 1887 ; ' The Present State of our Knowledge 

 concerning the Self-Purification of Rivers,' Internat. Congress of Hygiene and 

 Demography, 1891), Gr. Bischof (" Notes on Dr. Koch's Water Test," 'Journ. Soc. 

 Chem. Industry,' 1886), C. Fraenkel (" Unters. ii. Brunnendesinfection u. d. 

 Keimgehalt d. Grundwassers," ' Zeitschr. f. Hyg.,' vol. 6, 1889, pp. 23—61), Koch 

 (' Die Bekampfung der Infections-Krankheiten : Rede zur Stiftungsfeier der 

 Militararztlichen Bildungsanstalten,' 1888, p. 25), Plagge and Proskauer (' Zeitschr. 

 f. Hyg.,' vol. 2, 1887, p. 401), Wolff hugel ( <£ Erfahrungen ii. d. Keimgehalt 

 brauchbarer Trink- u. Nutz-Wasser," ' Arb. a. d. Kaiserl. Gresundheitsamt,' vol. 1, 

 1886, pp. 546 — 566), G-. Frank (" Die Veranderung des Spree-Wassers innerhalb und 

 unterhalb Berlin, &c," 'Zeitschr. f. Hyg.,' vol. 3, 1888, pp. 355—403), Schlatter 

 (' Der Einfluss des Ab-wassers der Stadt Zurich auf den Bacteriengehalt der 

 Limmat," 'Zeitschr. f. Hyg.,' vol. 9, 1890, pp. 56—58). See also 'Ann. d. l'lnstit. 

 Pasteur,' vol. 3, 1889, pp. 559 — 569 and our Appendix A, infra. 



