386 THE BEGINNINGS OF LIFE. 



hermetically sealed, these solutions were thus sufficiently 

 protected, to prevent the access of much dust from the 

 neighbouring fire. The fluid in one of the bottles was 

 allowed to remain neutral, whilst to that of the other 

 four or five drops of acetic acid were added, so as to 

 make it yield a faintly acid reaction to test paper. The 

 results were quite different in the two cases. Towards 

 the end of the fourth day the originally unaltered neutral 

 solution began to assume a cloudy appearance ; this in- 

 creased in amount during the next day, and at the close 

 of the sixth day a thin pellicle was found on the surface, 

 and beneath it there were some irregular, flocculent, 

 whitish masses buoyed up by small air bubbles. Ex- 

 amined microscopically, the pellicles and also the 

 flocculent masses beneath were found to be made up 

 of medium-sized plastide-particles and Bacteria, mixed 

 with crystals of triple phosphate. There were also 

 many scattered cells of a Torula, varying from -oVo" to 

 roWo" i n diameter. By this time (close of the sixth 

 day), however, the companion solution which had been 

 slightly acidified, had undergone scarcely any appreciable 

 change. It was still quite clear and transparent, and 

 there was no pellicle on the surface, though there was a 

 very slight whitish flocculent stratum at the bottom of 

 the bottle. Even on the twenty-first day this solution 

 continued in much the same condition still showing 

 no trace of a pellicle. The fluid itself was clear, and 

 there had been only a very slight increase in the thick- 

 ness of the white flocculent layer at the bottom of the 



