A HISTORY OF SCIENCE 



ours, though never absolutely identical, yet pass at 

 some stage through so similar an epoch that on each 

 and every one of them there is developed something 

 measurably comparable, in human terms, to what we 

 here know as living matter; differing widely, perhaps, 

 from any particular form of living being here, yet still 

 conforming broadly to a definition of living things. 

 In that case the life-bearing stage of a planet must be 

 considered as having far more general significance; 

 perhaps even as constituting the time of fruitage of the 

 cosmic organism, though nothing but human egotism 

 gives warrant to this particular presumption. 



Between these two opposing views every one is free 

 to choose according to his preconceptions, for as yet 

 science is unable to give a deciding vote. Equally open 

 to discussion is that other question, as to whether the 

 evolution of universal atoms into a " vital" association 

 mass from which all the diversified forms evolved, or 

 whether such shifting from the so-called non- vital to 

 the vital was many times repeated perhaps still goes 

 on incessantly. It is quite true that the testimony of 

 our century, so far as it goes, is all against the idea of 

 "spontaneous generation" under existing conditions. 

 It has been clearly enough demonstrated that the bac- 

 teria and other low forms of familiar life which formerly 

 were supposed to originate "spontaneously" had a 

 quite different origin. But the solution of this special 

 case leaves the general problem still far from solved. 

 Who knows what are the conditions necessary to the 

 evolution of the ever-present atoms into "vital" asso- 

 ciations? Perhaps extreme pressure may be one of 

 these conditions; and, for aught any man knows to the 



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