f0i- 



^ h 



270 



THE BEGINNINGS OF LIFE. 



as Cohn ^ thinks^ the later free-swimming stage in the 

 existence of certain algx, intermediate between Tal- 

 melU and Osclllatori^ ; or lastly (4) that they are 



I 



the first and most common developmental phase of 

 newly- evolved specks of living matter^ which are capa- 

 blCj either singly or in combination, of developing into 

 many different kinds of living things. 



Ehrenberg's is an almost obsolete point of view. 

 Bacteria are no more animal than vegetal organisms 

 they are protists. And few even of the firmest believers 

 in the constancy of specific forms would now be in- 

 clined to maintain this doctrine with respect to Bacteria. 

 The opinions of Hallier and Cohn will be again referred 

 to in other portions of this chapter. 



1 have been compelled to take the fourth view, 

 and to look upon plastide-particles as the mere tem- 

 porary and initial developmental form of many or- 

 ganisms which may afterwards present distinct cha- 



racteristics of their own^ 



though 



certain of these 



particles may, through default of the necessary con- 

 ditions, never actually develop into higher modes of 

 being. But a very large number of them undoubtedly 

 give rise to the bodies known as Bacteria^ by a direct 

 process of growth and development. These Bacteria 

 vary very considerably in size, and also in the 

 quality of their rnovements. Their size seems to 



^ ' Entwickelungs-geschichfe der Mikroscop.' Algen und Pilze, 1854. 

 2 Many of what may seem to be mere plastide-particles, are only 

 Bacteria seen endwise. 



been 



m 



their m» 



i»i : and they g 



) 



D 



lie, dividin 

 Mvements are 

 sdllating, or irn 

 times they 

 fke, either dir 



s. All 



wements w!::cl 



h tilings, anc 

 alone n 



\\ 



\ 



'^e to do 



I '' should 



be 



05 



erences i 



^ lower 



in siz 



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e 



1 



Or 



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form 



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