110 MICRO-OKGANISMS IN WATEll 



Herzegovina. This lake is situated about 403 metres 

 above tlie Adriatic Sea, and is partially surrounded by 

 high mountains, from which it is fed with snow-water. 

 The average of a number of examinations showed that 

 when the water was abstracted from the surface of the 

 lake about 200 m. distant from the shore, 4,000 micro- 

 organisms were found in 1 c.c. ; whilst close to the 

 shore, in the immediate neighbourhood of water-reeds, 

 which abound all along the banks, as many as 16,000 

 in a c.c. were present. Karlinski also examined the 

 water at different depths, and here great differences 

 were observable. These examinations were conducted 

 anaerobically as well, so that the maximum number 

 of microbes was detected. Whilst on the surface 

 4,000 were present, at a depth of 5 m. hardly 1,000 

 were found in the c.c. At a depth of 10 m. there were 

 rarely more than 600, and still lower down, 12 to 16 

 m., there were only from 200-300 present in the c.c. 

 At the bottom of the lake, when the mud was stirred 

 up, there were as many as 6,000 in the c.c. The above 

 figures were obtained from an average of sixty observa- 

 tions. 



The Lake of Zurich, according to Cramer,^ was 

 found to contain during the months of October and 

 December in the year 1884, and January, 1885 (taking 

 the average of fifty examinations), 168 in a c.c. In 

 June, 1884, an average of forty-two investigations 

 yielded only 71 in a c.c. 



The Lake of Lucerne was found to contain from 8 

 to 51 in a c.c. The latter number was obtained from 

 a shallower part of the lake, where the water was also 

 disturbed by steam-boat trafiic. 



Loch Katrine water, as delivered in Glasgow, was 



^ Die Wasserversorgung von Zurich. 



