156 PRINCIPLES OF SOIL MICROBIOLOGY 



Macfayden and Blaxall 33 in 1888, and other workers soon following 34 ' 35 

 that there are bacteria in the soil which are capable of growing at high 

 temperatures, namely at 50° to 70°C, and which refuse to grow in the 

 laboratory at room temperature. Various investigators 36 " 38 found in 

 stable manure organisms capable of growing at temperatures up 79.5°C. 

 Schloesing 39 demonstrated in 1892 that the self-heating and burning of 

 hay, cotton, manure, etc., is caused by microorganisms which he called 

 thermogenic bacteria. It may be here largely a question of thermo- 

 tolerant organisms rather than strict thermophiles. 40 Thermophilic 

 bacteria were found in sands of the Sahara Desert, 41 but are absent in 

 forest soils. The distribution of these organisms in the soil seems to 

 depend on the manure used. Garden soils heavily manured may con- 

 tain 1 to 10 per cent of the flora developing on the plate as thermophilic 

 forms, while field soils contain only 0.25 to per cent. Uncultivated 



33 Macfayden, A., and Blaxall, F. R. Thermophilic bacteria. Jour. Path. 

 Bact. 3: 87-99. 1894. 



34 Rabinowitsch, L. "fiber die thermophilen Bakterien. Ztschr. Hyg. 20: 

 154. 1895. Oprescu, V. Studien iiber thermophile Bakterien. Arch. Hyg. 

 33: 164. 1898. Schillinger, A. Uber die thermophilen Bakterien. Hyg. 

 Rundsch. 1898, p. 568. Tsiklinsky, P. On microorganisms living at high tem- 

 peratures. Russ. Arch. Pathol. 5, 1898 (Ambroz, A. tlber das Phanomen der 

 Thermobiose bei den Mikroorganismen. Centrbl. Bakt. I, Ref. 48: 257-279, 

 289-312. 1910). Sames, T. Zur Kenntnis der bei hoheren Temperaturen wach- 

 senden Bakterien und Streptothrixarten. Ztschr. Hyg. 33: 313. 1910. 



35 Blau, O. Ueber die Temperaturmaxima der Sporenkeimung und der Sporen- 

 bildung, sowie die supramaximalen Totungszeiten der Sporen der Bakterien, 

 auch derjenigen mit hohen Temperaturminima. Centrbl. Bakt. II, 15: 97-143. 

 1906. 



36 Burrill, T. J. The biology of silage. 111. Agr. Exp. Sta. Bui. 7. 1889. 



37 Schloesing, Th. Sur la fermentation formenique du fumier. Compt. Rend. 

 Acad. Sci. 109: 835-840. 1889. 



38 Dupont, C. Sur les fermentations aerobies du fumier de ferme. Ann. 

 Agron. 28: 289. 1902. 



39 Schloesing, T. Contribution a l'etude des fermentations du fumier. Ann. 

 Agron. 18: 5. 1892. 



40 Miehe, H. Die Selbsterhitzung des Heus. G. Fischer. Jena 1907. 

 Schiitze, H. Beitrage zur Kenntnis der thermophilen Actinomyceten und ihrer 

 Sporenbildung. Arch. Hyg. 67: 35-56. 1908. 



41 Negre, L. Bacteries thermophiles des sables du Sahara. Compt. Rend. 

 Soc. Biol. 74: 814-816. 1913. 



