20 Living and Dead Matter and 



of bacteria which oxidize thiosulphate to sulphuric 

 acid. They will develop if some Na 2 S 2 3 is added to 

 sea water. These bacteria can only develop if C0 a 

 from the air is admitted or when carbonates are pre- 

 sent. For these organisms the CO 2 cannot be replaced 

 by glucose, urea, or other organic substances. Such 

 bacteria must therefore possess the power of producing 

 sugar and starch from C0 2 without the aid of chloro- 

 phyll. Similar observations were made by Beijerinck 

 on a species of fresh-water bacteria. x 



Finally the case of iron bacteria may briefly be 

 mentioned though Winogradsky's views are not accepted 

 by Molisch. 



We may, therefore, consider it an established fact 

 that there are a number of organisms which could 

 have lived on this planet at a time when only mineral 

 7 constituents, such as phosphates, K, Mg, S0 4 , CO 2 , 

 \ and O 2 besides NH 3 , or SH 2 , existed. This would 

 lead us to consider it possible that the first or- 

 ganisms on this planet may have belonged to that 

 world of micro-organisms which was discovered by 

 Winogradsky. 



If we can conceive of this group of organisms as 

 producing sugar, which in fact they do, they could 

 have served as a basis for the development of other 

 forms which require organic material for their develop- 

 ment. 



1 Beijerinck, M., Folia Microbiologica, 1914, iii., 91. 



