Manchester Memoirs, Vol. Iviii. (1914), No. 8. 19 



tamination. In Thresh," we read that peaty water 

 may contain -oi parts per 100,000 of free ammonia, 

 associated with more albuminoid ammonia, and yet 

 be pure, and an analysis of peaty water given there 

 shows 001 of free ammonia and 024 of albuminoid 

 ammonia per 100,000 parts of water. We take it, 

 therefore, that Thresh means to convey that in peaty 

 water the albuminoid ammonia is always in excess of the 

 ammonia. This is borne out by an analysis of peaty free 

 waters given by Dachnowski.^^ For pure bog waters 

 his figures are -519 parts of free ammonia and i"034 

 parts of albuminoid ammonia per 100,000 parts of 

 water, and for lake water on the same island as the 

 bogs and presumably influenced by them the figures 

 are "295 and "45 parts per 100,000 respectively. In 

 both these cases the albuminoid ammonia is in excess 

 of the free ammonia, though not to the extent that 

 Thresh's figures give, where the albuminoid ammonia was 

 twenty-four times as great as the free. Still they bear 

 out Thresh's statement that, in cases of vegetable con- 

 tamination, the albuminoid ammonia is in excess of the 

 free. In the present instance, the amounts of free and 

 albuminoid ammonia are more or less equal, and there is, 

 therefore, an excess of free ammonia, over and above that 

 due to the peat contamination, to be accounted for. We 

 believe that this excess of free ammonia is derived from 

 the action of the bacteria of putrefaction, which, acting 

 upon decaying organisms, liberate free ammonia. We 

 have already pointed out that Rostherne Mere is very 

 rich in planktonic organisms, and these, dying and sink- 

 ing to the bottom, provide the material upon which the 



""The Examination of Water and Water Supplies," 2nd edit. 

 London, 1913. 



'* Botanical Gazette, July, 1911. 



