10 THE ORIGIN OF LIFE 



nature is great and insurmountable, and still more 

 so during the close of the nineteenth century has it 

 been supposed, not without good reasons, that biology 

 was sharply marked off from the a-biological sciences. 

 The boundary between living and dead matter was 

 supposed to be adequately defined, whereas we think 

 it now appears it can no more be laid down than that 

 between biology and psychology, or biology and 

 sociology. Between biology and physics it seems to 

 be indefinable. When we bear in mind the gradual 

 and continued simplification as we descend from the 

 most complex forms t6 the simplest atoms, it cannot 

 fail to attract the attention of the acute observer that 

 so also this continual dropping off of properties means 

 something. That the process is in the limit continu- 

 ous. This is the doctrine we propose to consider, 

 and which we may in the end be forced, whether 

 willingly or unwillingly, to accept as the most con- 

 sistent and scientific one. 



The processes we have to keep before our minds 

 are not merely those of metabolism, but also those of 

 continuity and continuous change. 



It is therefore not inconsistent with the idea of 

 biogenesis in its ultimate aspect, although it in- 

 volves heterogenesis in an extended sense ; or trans- 

 mutation, admitting that complex forms can be 

 evolved from simpler ones. Thus the theory of the 

 universality of potential life in matter may be 

 admitted without implying that such a change as 

 that involved in abiogenesis has taken or is taking 

 place. 



