44 THE BIOLOGICAL APPROACH 



in the dark before the door but is looking for it under the lamp-post, 

 because he can see better there (Winkler, 1960). But although he 

 also uses dead remains to study life, he himself has killed the living 

 organisms only a couple of moments before, by techniques known 

 to him and selected to provide the least distorted picture. 



NON-LIVING AND LIVING IN GEOLOGY 



The tools of geology, this must be stated quite clearly, are so much 

 coarser that for us this distinction between living and non-living is 

 not a practical question at all. The best we can hope for is to find 

 fossilized remains of organisms which formerly lived on earth. Only 

 very rarely do we have some idea of how these forms died — for 

 instance, when they were buried by volcanic ash, or slid into an 

 asphalt pool. Moreover, apart from the fact that we generally do 

 not know how our fossils-to-be died, we also have only the vaguest 

 ideas of why and how they were preserved, and how and when the 

 fossilization process, the replacement of the original organic material 

 by mineral matter, took place. Apart from the fossilized remains 

 themselves, we can study, as a further indication, the environment 

 in which these remains were buried in the rock and from these make 

 a considered guess about the environment in which the organism 

 that later became preserved as a fossil, had lived. 



To be at all recognisable as remnants of former living organisms, 

 fossils must have preserved some clearly organized shape or structure, 

 recognizable as such by the eye, by a hand lens or by with the aid 

 of a normal microscope. These remains of former living organisms, 

 preserved from the geologic past, are not merely dead, but long since 

 dead and fossilized. They can no more yield the fresh preparations 

 biologists study under the electron microscope or the extracts they 

 prepare in an ultracentrifuge. Our remains, let it be stated again, 

 are dead and fossilized. 



Organisms capable of being detected in a fossilized state by a 

 geologist after billions of years may well belong to the 'lower' organ- 

 isms, to unicellular forms as bacteria or certain algae; in short, to 

 microbes. But the organization of such forms has progressed already 

 a long way from that borderland between living and non-living the 

 biologist is interested in. Fossilized remains from the early history 

 of life must already show some cellular structure. There is little 



