THE SIMPLEST FORMS OF LIFE 31 



particle of plasm. As the embryonic development roughly 

 reproduces the past history of a species, we take it that the 

 initial stage represents a very early ancestor of all species. 

 In any case, no biologist conceives the first living things to 

 have been more advanced than the lowest organisms we 

 have to-day. 



We must, therefore, take one of the simplest of living 

 organisms and carefully examine its life. And here I must 

 emphasise once more, for the sake of the inexpert reader, 

 that no evolutionist supposes the first living things were even 

 so far advanced in organisation as the tiniest and simplest 

 things that now live. No one supposes that one fine day an 

 alga or a bacillus made its appearance suddenly in the 

 primitive ocean. In that event we should indeed have a 

 very difficult problem to face in the origin of life. We 

 assume that a vast number of stages preceded that linked 

 the living particle of plasm to the natural compounds of the 

 inorganic world. It is a matter of assumption, remember, 

 on any hypothesis. The theologian, Sir Oliver Lodge, and 

 all the rest of us have to assume our starting-point. Life 

 began in some form unknown to us, but certainly not in a 

 form more complex than the simpler forms we know. For 

 the moment, I merely want to insist that the early forms 

 may have been even simpler, infinitely simpler. Very much 

 simpler forms would have little stability, like Mr. Burke's 

 radiobes, and would disappear. But some biologists hold 

 that they are being reproduced daily. 



Let us take, to begin with, one of the simpler forms of 

 life known to us and analyse its structure and life. You will 



