116 The Bible of Nature 



The belief rested on misinterpretations not un- 

 natural at times when microbes were unknown, or 

 when the life-histories of common parasites were 

 very dimly discerned, or when no one dreamed 

 of the minuteness and ready transportability of 

 the germs of even worms. It was supposed that 

 thistles arose de novo from the dust, that bees 

 sprang from dead oxen, that frogs were engendered 

 from the mud. 



But though many thoughtful biologists, such as 

 Huxley and Spencer, Nageli and Haeckel, have 

 accepted the hypothesis that living organisms of 

 a very simple sort were originally evolved from 

 not-living material, they have done so rather in 

 their faith in a continuous natural evolution, than 

 from any apprehension of the possible sequences 

 which might lead up to such a remarkable result. 

 The hypothesis of abiogenesis may be suggested 

 on a priori grounds, but few have ventured to 

 offer any concrete indication of how the process 

 might conceivably come about. To postulate 

 abiogenesis as if it were a matter of course betrays 

 an extraordinarily easy-going scientific mood. 



Some Concrete Suggestions. One of the few con- 

 crete suggestions is due to the physiologist Pfluger 

 (1875), whose views are clearly summarized in 

 Verworn's "General Physiology." Pfluger sug- 

 gested that it is the cyanogen radical (CN) which 

 gives the " living" proteid molecule its character- 



