364 THE BEGINNINGS OF LIFE. 



partially preserved. The reaction of the fluid was found 

 to remain slightly acid. 



On microscopical examination of the sediment, Bac- 

 teria were found, having moderately active movements 

 though they were not very numerous. There were 

 many granular aggregations, from the midst of which 

 were growing Leptotkrix filaments, though the organisms 



FIG. 25. 



Torula, Leptothrix, and Bacteria found in simple Solution of 

 Ferric and Ammonic Citrate. ( x 800.) 



which were most abundant were Torula cells of different 

 sizes, many of which were provided with a segment 

 across their short diameter, whilst each half contained 

 a nuclear particle. These Torula cells had a uniform 

 very faint greenish hue, and homogeneous contents. 

 They often existed in groups of 1 3-20, or more. 



Experiment 2. A closed flask containing a solution of 

 ferric and ammonic citrate, together with a few minute 

 fibres of deal wood (much less than half a grain), was 

 opened 42 days after it had been hermetically sealed. 



The fluid continued clear and there was no pellicle on 

 the surface, though, after the first two weeks a slight 



