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 Mendeléeff indicated, with their small 
atomic weights.* 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 
‘Letter to New Statesman, June 8, 1918, p. 191. 
