458 



Annals New York Academy of Sciences 



impregnation by the method of Zettnow. Both bacteria found in the Pre- 

 cambrian seem to be closely related to each other. 



A list of biochemical data of the isolated germs from paleozoic salts is given 

 in TABLE 1. 



# 



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W%Bi 



I V 



Figure 4 (Top). Bacterium from the Silurian, strain XV/1, enlargement 1200:1. 



Figure 5 (Bottom). Bacterium from the Precambrian salt, strain XXX/1, enlargement 

 1200:1. (The pictured bacteria are probably the oldest known living organisms with their 

 approximate age of 650 million years.) 



I have not yet examined salts from the Carboniferous. The bacteria from the 

 Precambrian, Silurian, and some from the Devonian show only few biochemical 

 properties. The "younger" these germs are, the more they are able to perform 

 biochemically, only to lose this ability in later life, as shown in the comparison 



