ORIGIN OF LOWEST ORGANISMS. 



b. That they represent subordinate stages in the 

 life-history of other organisms (fungi), from some 

 portion of which they have derived their origin, and 

 into which they again tend to develop. 



c. That they may have a heterogeneous mode of 

 origin, owing to the more complete individualization 

 of minute particles of living matter entering into the 

 composition of higher organisms, both animal and 

 vegetal. 



d. That they may arise de novo in certain fluids 

 containing organic matter, independently of pre- 

 existing living things (Archebiosis). 



I shall make some remarks concerning each of these 

 views, though the evidence I have to adduce mainly 

 concerns the possibility of the origin of Bacteria and 

 Torukz in the way last alluded to, viz., by Archebiosis. 



The third mode of origin is what is called He- 



o 



terogenesis ; whilst the first and second modes are 

 the representatives of more familiar processes, in- 

 cluded under the head of Homogenesis. Thus, in 

 accordance with the first view, Bacteria may be 

 regarded as low organisms having a distinct indi- 

 viduality of their own and multiplying by a process 

 of fission thus affording instances of what I propose 

 to term direct Homogenesis. Whilst, in accordance 

 with the second view, Bacteria are supposed to repre- 

 sent merely one stage in the life-history of higher 

 organisms, which are therefore reproduced by an in- 

 direct or cyclical process of Homogenesis. 



