THE SIMPLEST FORMS OF LIFE 41 



energies, it becomes difficult to draw the line. When a man 

 is convinced on other grounds that there is a spiritual 

 principle in living things, he can, no doubt, make capital 

 of the temporary gaps in the biological scheme. It is not 

 logical, though it may be impressive. But one would like 

 to hear of the competent biologist who would admit the 

 mechanical nature of thousands of the earliest species of 

 living things, and then postulate a spiritual principle for the 

 rest. Defective as our knowledge is, it makes such a 

 suggestion seem ridiculous. We have so nearly complete 

 an evolutionary scheme that there are few biologists living 

 who doubt that all the actual animals and plants have been 

 developed from the primitive unicellular organisms. The 

 next chief stage is a cluster of cells, each of which lives its 

 own life, and may even detach itself and live like an amoeba. 

 One would hardly say that it needed an immaterial principle 

 to bring in the obvious advantage of sticking together. The 

 next chief stage (as in the Pemmatodiscus) is that the cluster 

 which is hollow, each cell having to be at the surface to 

 get its nourishment doubles in on itself, like an india-rubber 

 ball. The inner cells then confine themselves to digestion 

 and reproduction ; the outer to locomotion and reaction on 

 stimuli. This is well within the range of natural selection. 

 The simple worm-like body is a natural development from 

 this ; and we have an illuminating series of forms between 

 that and the fish, the fish and the mammal, the lower 

 mammal and man. 



But, before we press the subject any further, it will be well 

 to invade Sir Oliver Lodge's own science, and ask the 



