BACTERIAL CONTENTS OF VARIOUS WATERS 89 



Thus Miquel l found as many as 40,000,000 per c.c. 

 in the water which had been used for the soaking of 

 clothes prior 'to the use of soap in the floating laundries 

 of the Seine. 



Blasius 2 found 2,980,000 in a water used for manu- 

 facturing purposes. 



In an investigation of the drainage of Essen, Wahl * 

 found from 1,686,000 to 5,248,000 in a c.c. 



Eaw sewage was found by one of us to contain as 

 many as 26,000,000 per c.c. ' 



During the last few years a very large number 

 of experiments have been made to ascertain the bac- 

 terial contents of different rivers from which cities 

 and towns derive their water supplies. It will be in- 

 teresting in the first place to consider some of these 

 examinations before entering into more detail concern- 

 ing the treatment which such waters receive before 

 distribution. 



Rivers. London, as is well known, derives the 

 greater portion of its water-supply from the rivers 

 Thames and Lea. These rivers were first made the 

 subject of careful bacteriological observation by one of 

 us, 4 and at the request of the Local Government Board 

 these investigations were carried out systematically, 

 and were published in the monthly reports furnished 

 by the Board. The following table gives the number 

 of micro-organisms found in the Thames and Lea, above 

 the intakes of the several companies drawing from 

 these sources, for each month during the years 1886, 

 1887, and 1888. 



1 ' De la Eichesse en Bacteries des Eaux d'Essangease,' Revue 

 d'Hygiene, vol. viii. p. 388. 



~ MonatsTieft fiir offentliclie Gesundlieitspflege, no. 5 and 6, 1885. 

 Braunschweig. 



3 Centralblatt fiir allgemeine Gesundlieitspflege, vol. i. Bonn, 1886. 



4 Local Government Board Beports, 1885, 1886, 1887, 1888; also 

 ' Secret Friends and Foes,' Percy Frankland, 1893. 



