204 life's beginning on the earth 



material. We find that living tissue also contains crystal- 

 line units. It is now less surprising that ordinary salt- 

 crystals may assume life-like forms. They have taught us 

 an important truth, as they leave the stage, but we want to 

 learn more. 



The invisibly small viruses or "living molecules" seem 

 promising. They teach us how life may have arisen, how 

 chemistry rules and regulates it. But we ought to be 

 able to make such molecules artificially, to make a living 

 pure substance, or "self-reproducing enzyme." Why can't 

 chemistry do it? The research chemist tells us this is 

 asking too much. "Give me several more centuries," he 

 says, shrugging a shoulder; "it is a short period in view of 

 the fact that life started on the earth a billion years ago." 

 The parade passes on. 



"Life came from the ocean" is the catch-word of the next 

 group that passes in the parade; "study salt and water, 

 as well as the forms which they produce, and you will find 

 the secret of life." We follow their advice faithfully, and 

 are indeed rewarded. We learn about the expanding and 

 constricting force of osmotic pressure. How these ambi- 

 tious osmotic structures stretch and grow! Do they not 

 look like real plants? Even expert botanists are fooled. 

 We acclaim them enthusiastically. Still there is the air of 

 failure about them; they are too brittle, too transient; their 

 their poor mineral bodies cannot compete with organic 

 structures. So the suggestion comes to us: why not make 

 osmotic structures of real organic material, preferably by 

 means of enzymes? But before we can explore the sug- 

 gestion the parade has passed on. 



Enter the last group, to show why and how living things 

 move 1 around. Indeed those little oil-drops are quite suc- 

 cessful in teaching us the elements of motion in the living 

 world; bul the essence of the action of a real muscle remains 

 obscure. We invoke that modern goddess, electricity, to 

 explain to us how the nerves may function: she shows us 



