487 
of Edinburgh, Session 1885-86. 
amount per gramme of the original sewage. The following are 
examples of results obtained from London sewage : — ■ 
Colonies per grin. 
London sewage, June 1885, .... 1,490,000 
London sewage, July 1885, .... 4,226,804 
London sewage, November 1885, . . . 773,800 
It is therefore evident that the sewage is considerably influenced 
by season, containing more in the summer than in the winter 
season, hut for the most always yielding colonies approaching to or 
