THE BEGINNINGS OF LIFE. 455 



twenty- four hours, both varieties of 'Bacteria had 

 notably increased in quantity, and had become some- 

 what larger, though their movements were not at all 

 more active. 



Experiment o. An infusion of hay, which had become 

 slightly darker by the exposure to heat, and in which 

 a fine flocculent sediment had been thrown down. 



The flask was opened at the end of the seventh 

 week, the vacuum being still well preserved. The 

 reaction of the fluid was then found to be acid, and its 

 odour was hay-like though somewhat altered in character. 

 No organisms of any kind were discovered in the fluid, 

 or amidst the minutely granular deposit. 



Experiment p. An infusion of turnip (not neutralized 

 but in its natural slightly acid condition) was found to 

 have assumed the colour of pale sherry when removed 

 from the digester. There was also a small amount of 

 light flocculent sediment. 



The flask was opened eight weeks afterwards; the 

 vacuum having been well preserved. The reaction of 

 the fluid was still acid, and its odour was that of baked 

 turnip. There was a considerable quantity of granular 

 matter at the bottom of the flask, but after careful 

 microscopical examination, no organisms of any kind 

 could be detected x . 



1 Compare the results of this experiment with those of Nos. a and 

 g. The very slight addition of dilute liquor potassae to the latter 

 fluids seems to have been the immediately determining cause of their 

 productiveness (see p. 383). Some other experiments recorded in 



