THE BEGINNINGS OF LIFE. 357 



fluid itself a number of medium-sized, unsegmented 

 Bacteria, whose movements were somewhat languid l . 



Experiment 2. A closed flask containing a filtered 

 infusion 2 of turnip, was opened five days after it had 

 been hermetically sealed. 



On the second day after the flask had been sealed, 

 the previously clear solution began to exhibit a cloudy 

 appearance. The next day a reticulated scum was seen 

 on the surface of the fluid, which gradually became 

 more manifest on the two following days. When the 

 neck of the flask was opened, its contents were found 

 to emit a most foetid, sickly odour. 



Microscopical examination revealed Bacteria, and a 

 very large number of Vihnones mostly without joints 

 some straight and others bent, some motionless and 

 others exhibiting languid movements. These, mixed 

 up with a thickly interlaced network of Leptothrix 



1 This experiment was one of a series of six, in which the same hay 

 solution was employed (see Appendix C, pp. xlii-xlvi). A flask in 

 which the hay solution had been boiled without any addition of carbolic 

 acid, and which had been sealed after the solution had become cool and 

 the flask was full of ordinary air, yielded no organisms. 



2 This and other infusions of a similar nature have been prepared by 

 cutting a portion of white turnip into small thin slices, and then pour- 

 ing warm water upon them (in a suitable vessel) up to rather above 

 the level which they alone had reached. The infusions were then 

 allowed to stand near a fire for three or four hours, so as to keep them 

 at a temperature of from iio-i3OF. Nothing is easier than to obtain 

 negative results in such experiments : it is only necessary to use weak 

 infusions, more especially if, during their preparation, they have been 

 kept for a prolonged period at a temperature near to that of boiling 

 water, instead of at a heat which can be supported by the finger. 



