MAKING A HOME FOR LIFE 217, 



enter into the greatest number of reactions/' :< The 

 unique properties of hydrogen, carbon, and oxygen, 

 of water and carbon dioxide, are uniquely favor- 

 able to the existence of the greatest possible 

 number, variety and quantity of components of 

 systems." 



Along with the special properties of carbon, 

 hydrogen, and oxygen, we must think of their very 

 wide distribution, which again may be associated 

 causally, as Mendeleeff indicated, with their small 

 atomic weights. 1 Continuing our story, we see the 

 interest of an idea which Professor Chamberlin 

 suggests, that the pores of the growing soil might 

 afford " an adequate mechanism for holding, 

 protecting, and preserving the products of each 

 successive step in such a way as to favor the next 

 synthetic step." And whether " spontaneous gene- 

 ration " took place in the pores of the soil, or 

 whether the appearance of living organisms was due 

 to factors which remain outside the scientific uni- 

 verse of discourse, it is certain that the natural 

 conditions were propitious. Thus the soil supplies 

 a sort of circulatory mechanism for bringing in 

 supplies and carrying away waste. There is an intri- 

 cate canal system of capillary spaces and air-ducts in 

 the soil. Nothing could be better for the young 

 forms of life, however these arose. 



Of incalculable importance has been throughout 

 the ages the persistent circulation of matter, and 

 the meteorological cycle in particular. Water 

 1 Letter to New Statesman, June 8, 1918, p. 191. 



