ORIGIN OF LOWEST ORGANISMS. 73 



interlaced Leptothrix filaments. Bacteria also existed 

 abundantly in the fluid, though their movements were 

 very languid. 



c. Fluid in a Bent Neck Flask, having Eight acute Flexures. 



No. XVIII. Simple Turnip Infusion after forty-eight 

 hours showed no change. It was kept in water-bath for 

 twelve days, and during the whole of this time the 

 fluid remained quite clear. The tube was then broken 

 \\ inch above the bulb (which was re-immersed in the 

 bath), leaving the fluid exposed to the air through the 

 straight open tube. The fluid at this time was odour- 

 less, and its re-action was still faintly acid. 



The infusion remained thus exposed for six days 

 without undergoing any apparent change. On the 

 eighth day a very slight whitish sediment was noticed, 

 which had increased in quantity by the tenth day, 

 though there was still no trace of general turbidity. On 

 the eleventh day some of the sediment was examined 

 in a drop of the fluid, and it was found to be wholly 

 composed of rather large Torulcz cells the largest being 

 about -g-oVo" in diameter, though all the smaller sizes 

 were abundantly represented. Not a single Bacterium 

 or Vibrio could be detected, and the fluid was still 

 quite odourless.* 



This again is a most instructive experiment when compared 

 with Nos. XVI. and XX., in which portions of the same infusion 

 were employed. The results in No. IX. would lead us to believe 

 that a vegetable infusion which does not ferment, does, never- 

 theless, undergo some changes in molecular composition, and 

 this notion seems to derive confirmation from the present ex- 

 periment. Some of the same solution which has been kept for 

 a time (twelve days) from contact with atmospheric particles, 

 subsequently, even when fully exposed to the air, undergoes no 



