'FUNGUS' IN SEWAGE CONTAMINATED WATER 73 
Leptomitus, Sphaerotilus, the zooglea forming bacteria, and Carchesium Lach- 
manni, all indicate a water which contains special food stuffs derived from sewage ; 
they also indicate aeration. Leptomitus indicates the least amount of contamination 
and the greatest amount of aeration ; the zooglea masses are present in concentrated 
sewage, and Sphagrotilus and Carchesium hold intermediate places. 
These organisms perform a very important function — they follow up and 
complete the work of the bacteria in breaking up organic matter ; they are succeeded 
by higher forms of fHii 1 1 1 .1l- life — the Diatomaceae and the Green Algae, whilst these »~t^^*^v 
in their turn give place to the fishes and green plants. The 'sewage fungus,' 
therefore, plays a very considerable share in the self-purification of water. 
K 
