GREAT STEPS IN ORGANIC EVOLUTION 843 



life, it is well that the problems should be stated and the steps 

 envisaged. 



ORIGIN OF ORGANISMS.— It is probable that the earth as a 

 planet is some 2,000,000,000 years old, and it is probable that far 

 more than half of that unthinkable time was spent before the crust 

 became cool enough and moist enough to be a home for living 

 creatures. Perhaps these emerged 300,000,000 years ago, but some 

 calculations, which are not guesses, give three times more. Since 

 protoplasmic life can only continue below a certain limit of tempera- 

 ture and demands, as a sine qua non, water in a liquid form, its 

 emergence must not be pushed back beyond the time when the earth 

 fulfilled these conditions. Our question is how did organisms begin 

 to be upon the earth. Some thinkers regard it as almost impious to 

 go beyond the theological or religious answer: that "Protoplasm is 

 a handful of dust that God enchants". In other words, living 

 creatures arose in a manner beyond Science — as an expression of 

 the Creative Will. But however true this may be transcendentally, 

 it is not a scientific answer. It involves a premature abandonment of 

 the scientific quest, though it will not and cannot be affected by any 

 scientific answer that may be found. 



Another position is that of the scientifically agnostic : Ignoramus ; 

 and as a matter of fact no one knows how living creatures began to 

 be upon the earth. The problem cannot be an easy one; there is not 

 in biological experience any known exception to the conclusion — 

 omne vivum e vivo ; we are not even sure that life ever began ; perhaps 

 we are not putting the question in the right way. But admirable as 

 this scientific reserve may be, it is a little too superior. In any case, 

 while it may be too soon to answer a question, it is never too soon 

 to ask it, if we can ask it well. And that requires some trying. 



Thus after bowing to the theological and the agnostic positions, 

 we find oiurselves before two answers. The first, associated with 

 the names of Kelvin and Helmholtz, Richter and Arrhenius, and 

 therefore not to be brushed aside, is that minute germs of life may 

 have come to the earth from elsewhere, ensconced in a meteorite or 

 wafted with cosmic dust. It has been shown by Becquerel and 

 others that simple and quiescent forms of life can survive prolonged 

 exposure to extreme conditions of temperature, drought, and 

 scarcity of oxygen. Life in its simplest forms is very hard to kill, 

 audit may have come to the earth from elsewhere. But this would 

 leave quite untouched the problem of its origin "elsewhere". 



The other answer is the evolutionist one, that the living may have 

 arisen from the not-living by some process of natural synthesis, 

 comparable to the laboratory achievements of the chemist who 

 builds up compounds like grape-sugar, oxalic acid, indigo, caffein, 

 adrenalin, thyroxin, and so forth. The proteins, which are the most 



