ORIGIN OF LOWEST ORGANISMS. 89 



and in forty-eight hours there was a slight bluish-white 

 turbidity. In seventy-two hours the turbidity was well 

 marked, and there was a very thin pellicle on the sur- 

 face. When examined microscopically the fluid was 

 found to contain multitudes of very active Bacteria, 

 and the pellicle was also composed of an aggregation of 

 Bacteria. On the thirteenth day the opacity had some- 

 what increased ; there was also a well-marked pellicle, 

 and an obvious deposit. The pellicle was found to be 

 composed of Bacteria, and in the fluid there were mul- 

 titudes of medium-size Bacteria and Vibriones, with here 

 and there a small Toriila cell.* 



* On comparing the corresponding experiments of series 

 XLVIIL LI. with those of series LIII. LVI. less difference 

 is found than might have been expected by many. The com- 

 parison of the numbers of each series with one another, also 

 reveals the interesting fact, that the mere presence of N, C, O, 

 and H, is not all that is required, even for the growth and nutrition 

 of the lower living things. These elements seem to lapse into 

 the new combinations constituting living matter of various kinds, 

 more easily from certain pre-existing states of combination than 

 from others. Solutions of ammonic tartrate are much more 

 favourable starting points for the new combinations than solu- 

 tions of ammonic acetate. The comparison of experiment No. 

 LI. with No. LI I. is extremely interesting in reference to the 

 dogma that phosphorus is a necessary ingredient in living matter. 

 Solutions of the ammonic tartrate in distilled water have been 

 twice analyzed for me by a skilled chemist, without revealing the 

 least trace either of phosphorus or sulphur. This result is very 

 remarkable when compared with the amount of living matter 

 which may so soon appear in such a solution : the number 

 of the organisms and the rapidity of their evolution, being 

 almost equal to that which occurs in a similar solution to which 

 a phosphate has been added. However much, therefore, phos- 

 phorus may aid the development of organisms in many fluids, 

 there is still an important difference between many and all, 



which 



