234 MICRO-ORGANISMS IN WATER 



111 the great majority of the experiments referred to, 

 the waters in which bacterial multiplication took place 

 were kept in vessels to which the air had free access 

 through cotton-wool stoppers, and although there is 

 still deficient information on this point, we have reason 

 to believe that the free access of air in this manner is 

 favourable to such multiplication, and that if the waters 

 are kept in closed bottles filled nearly to the stopper 

 the multiplication may be much less marked. Thus a 

 sample of Thames water was recently taken by one of 

 us at Hampton in a Winchester quart bottle nearly filled 

 to the stopper, and in this bottle the water was allowed 

 to remain untouched for seven days, the average tem- 

 perature to which it was exposed during this interval 

 being about 10 C. At the end of the seven days the 

 water exhibited 300 bacteria per 1 c.c., it was then dis- 

 tributed in sterile flasks plugged with cotton-wool, and 

 these flasks were maintained at 8 C. and 19 C. in a 

 refrigerator and incubator respectively, and on being 

 submitted to bacteriological examination from time to 

 time yielded the following results : 



Number of Bacteria in 1 c.c. of Thames Water (Hampton) 

 (Percy Frankland) 



Kept in flask plugged \vith cotton-wool 

 .Juno, is'.c; 8 C. 19 C. 



On the 6th day 560,000 45,000 



,. 12th 166,000 30,000 



.. 19th 58,000 31,000 



It is thus obvious that during the sojourn of the 

 water in the stoppered bottle practically no multiplica- 

 tion can have taken place, whilst on introducing this 

 water into flasks plugged with cotton-wool extensive 

 multiplication ensued. This multiplication must have 

 been very rapid and have been followed by a very 



dcs Sciences liolor/ujiicK. publiees par 1'Institut imperial de Medecine 

 experimentale, a St 1'etersbourg, 1892 ; "Warington, Chem. Soc. Journ. 

 1891, 484. 



