268 THE BEGINNINGS OF LIFE. 



which we shall subsequently speak, are very often found 

 in both situations. 



With regard to the mode of origin and nature of 

 'Bacteria^ much difference of opinion still exists. They 

 have been supposed by some persons to result from the 

 coalescence and fusion of plastide-particles ; whilst 

 the longer and more developed bodies, called Vtbriones^ 

 have been thought to result from a similar union of 

 "Bacteria. 



This is the view of M. Dumas and of Dr. Hughes 

 Bennett, though it is doubted by Pouchet and most 

 other observers. It seems much more probable that 

 both Bacteria and Vibriones are only later stages in the 

 growth and development of certain primary plastide- 

 particles. Dr. Bennett 1 states that he has actually 

 seen the union above referred to taking place ; but, 

 judging from my own experience, I should say that it 

 is an occurrence of the most extreme rarity. During 

 a very long series of observations I have never per- 

 ceived such a coalescence. 



The most discordant opinions have always existed 

 as to the nature of these 'Bacteria. Naturalists have 

 been in doubt as to whether they should be regarded 

 as independent living things of the lowest grade, 

 having an individuality of their own ; or whether, 

 rather, they should be looked upon as developmental 

 forms of some higher organisms either animal or 

 vegetal. There seem to be four principal views con- 



1 'Pop. Science Rev.,' Jan. 1869. 



