THE BEGINNINGS OF LIFE: 



153 



taken pla^^ ' 



' in size; it^ ' 



membrane, 

 properties 

 ^n those dajs 

 lowest 



I 



s ' unicelliilai 



:^^*^ 







AF 



s. 



• p 



.332- 





organisms/ closely approximating in their characters to 

 the morphological units of which the higher plants and 

 animals were compounded. But, since our knowledge 

 has increased, since we have become more familiar 

 with the various living things which now constitute 

 the lowest groups of the third organic kingdom — pro- 

 tista — the maintenance of such doctrines (leaving 

 aside all other reasons) has become impossible. Have 

 we not seen that although the Frotoplasta are amoe- 

 boid animals^ possessing the old cell characters — that 

 is, having a distinct nucleus and a definite bounding 

 membrane — there are, nevertheless, adult animals 

 entering into the composition of the lowest group 

 Monera^ some of which have no bounding membrane 

 though they have a nucleus, whilst others, simpler 

 still, are mere bits of protoplasm, naked, non-nucle- 

 ated, structureless? Yet, such minute, homogeneous, 

 and altogether indefinite bits of protoplasm, are as 

 capable of displaying the fundamental characteristics of 

 Life as are the more definite unicellular organisms, to 

 which such attributes were previously supposed to be 

 restricted. Without visible structure they nevertheless 

 assimilate materials from their environment, and grow. 

 They constantly vary their form^ and are capable of 

 executing slow movements. 



Though 



possessing no 



nucleus, they, nevertheless, are able to divide and 

 reproduce their kind. 



Dr. Lionel Beale, whilst admitting the existence of 

 a morphological unit answering to the cell of other 



