98 PRINCIPLES OF SOIL MICROBIOLOGY 



of pure carbon by bacteria, certain investigations 100 point to positive 

 results and others 101 to negative results. 



Bacteria oxidizing carbon monoxide. Carbon monoxide is produced, 

 in large amounts, in the incomplete combustion of carbon compounds 

 and, in small amounts, in the decomposition of manure. 102 It can be 

 oxidized, not only chemically, but also by microorganisms. B. obligo- 

 carbophilus (Carboxydomonas oligocarbophila Orla-Jensen), isolated 

 from the soil, could purify the laboratory air rich in CO. 103 The organ- 

 ism was cultivated on simple inorganic media free from any other carbon 

 sources. It was found to be a small rod (0.7 to 1.0 by 0.5/x), non- 

 motile, the cells being united into irregular masses by a slimy substance. 

 The CO is utilized as a source of energy and is oxidized to C0 2 . 104 

 It is interesting to note that the organism developing under these condi- 

 tions was later found to be an actinomyces. 105 



Bacteria oxidizing hydrogen. Hydrogen can be oxidized both aero- 

 bically and anaerobically. De Saussure 106 demonstrated in 1838 that 

 moist soil will transform hydrogen readily into water, while soil heated 

 or treated with antiseptic substances is unable to do so. A number of 

 bacteria were isolated 104 - 107 from soils which were able to oxidize hy- 

 drogen autotrophically with the formation of water. The organism 

 isolated from the soil by Kaserer {Hydrogenomonas pantotropha (Kaserer) 

 Orla Jensen) was an aerobic, short, motile rod, 1.2 to 1.5 by 0.4 to 0.5^ 

 in size, occurring singly or in chains, encapsulated. It was motile by 



100 Galle, E. Uber Selbstentzi'vndung der Steinkohle. Centrbl. Bakt. II> 

 28: 461-473. 1910. 



101 Schroeder, H. The bacterial content of coal. Centrbl. Bakt. II, 41: 

 460^69. 1914. 



102 Lohnis, 1910, p. 542. 



103 Beijerinck, M. W., and Van Delden, A. tjber eine farblose Bakterie, deren 

 Kohlenstoffnahrung aus der atmospharischen Luft herrnhrt. Centrbl. Bakt. II, 

 10: 33-47. 1903. 



104 Kaserer, H. Die Oxydation des Wasserstoffes durch (Mikroorganismen. 

 Centrbl. Bakt. II, 16: 681-696, 769-775. 1906. 



108 Lantzsch, 1923 (p. 298). 



106 de Saussure, Th. Action de la fermentation sur le melange des gaz oxygene 

 et hydrogene. Mem. Soc. phys. Hist. Nat. Geneve, 8: 163-190. 1839. 



107 Niklewski, B. Ein Beitrag zur Kenntnis wasserstoffoxydierenden Mikro- 

 organismen. Centrbl. Bakt. II, 20: 469-473. 1908; Niklewski, B. tlber die 

 Wasserstoffoxydation durch Mikroorganismen. Jahrb. Wiss. Bot. 48: 113-142. 

 1910. Nabokich, A. J., and Lebedeff , A. F. t)ber die Oxydation des Wasserstoffes 

 durch Bakterien. Centrbl. Bakt. II, 17: 350-355. 1906; Biochem. Ztschr. 7: 

 1-10. 1908. 



