ENERGY TRANSFORMATION 385 



teria, 1 some thiosulfate bacteria 23 and some iron bacteria. 4 These are 

 the facultative autotrophic organisms. 



With the exception of the chlorophyll-containing plants, all organ- 

 isms derive their energy from the substances (nutrients) used for their 

 metabolism. There is a definite relation between the energy trans- 

 formation and the synthesis by the organism, depending upon the 

 nature of the nutrients and nature of the organisms. 



Lavoisier was the first to suggest that metabolism consists in the 

 oxidation of carbon compounds. This idea was further developed, in 

 two distinctly different directions, by Pasteur 5 who discovered the 

 true or anaerobic fermentations and by Winogradsky who discovered 

 the oxidation of inorganic substances. The earlier idea of Pasteur on 

 the intramolecular shift of oxygen, or as it would be termed today 

 "oxidation-reduction process," has found recently further confirmation 

 in the work of Neuberg and others on the formation of pyruvic acid in 

 alcoholic fermentation. It can be generally stated that the displace- 

 ment of oxygen within the molecule is the cause of considerable genera- 

 tion of heat of reaction. Fats cannot be, therefore, decomposed 

 under anaerobic conditions, because they contain insufficient oxygen. 



In the case of autotrophic bacteria there is a lack of correlation 

 between the oxidation of nutrients, oxygen intake and carbon dioxide 

 production. These organisms utilize inorganic substances exclusively 

 for the construction of their body tissues. This points to the fact that 

 the problem of energy transformation in microorganisms is a different, 

 problem from that of the transformation of nutrients in synthesis. 

 While an autotrophic organism may obtain its nutrients (minerals, 

 nitrogen source) from the same materials as an heterotrophic organism, 

 the energy and the carbon are obtained from two distinctly different 

 sources. 6 



The transformations of energy are based upon the fundamental 

 laws of thermodynamics. Energy cannot be destroyed, nor can it be 

 created. This law formulated by J. R. Mayer and H. Helmholz desig- 



1 Niklewski, B. tlber die Wasserstoffoxydation durch Mikroorganismen. 

 Jahrb. wiss. Bot., 47: 113-142. 1910. 

 2 Trautwein, 1921 (p. 87). 



3 Beijerinck, M. W. Chemosynthesis at denitrification with sulfur as source 

 of energy. K. Akad. v. Wetenschapen, Amsterdam, 22: 899-908. 1920. 



4 Molish, H. Die Pflanzen in ihren Beziehungen zum Eisen. Jena. 1892; 

 Die Eisenbakterien. Jena. 1910; Cholodny, 1926 (p. 94). 



5 Pasteur, L. Etudes sur la biere. Paris. 1876. 



6 Meyerhof, 0. Zur Energetik der Zellvorgiinge. Gottingen. 1913. 



