RESPIRATION AT THE EXPENSE OF MINERAL SUBSTANCES 1 53 



know that some bacteria are able to use coal, peat, paraffin oil 

 and other substances which are very hard to assimilate. With- 

 out doubt in these cases there is a synthesis of sugar which then 

 serves as respiratory material. The products of the oxidation 

 of methane are not different from the normal products of respira- 

 tion in the case of sugar nutrition. 



Oxidations of other mineral substances might perhaps be 

 utilized for respiration by some bacteria and new discoveries 

 in this field are not precluded. It is worthy of note that bac- 

 teria which effect chemical synthesis respire at the expense of 

 mineral substances. The simple oxidations of mineral sub- 

 stances, which do not form the basis of compHcated proc- 

 esses of many stages and which proceed as ionic reactions with 

 a velocity too great for measurement, appear to be especially 

 peculiar in furnishing the extraordinarily large amounts of 

 energy which are necessary for the accomplishment of chemical 

 synthesis. 



