CHAPTER VI 



Anaerobic Bacteria 



Oxygen tension in the growth of bacteria. Pasteur 1 was the first to 

 demonstrate that there are organisms, among them yeasts, which can 

 live in the presence of only small traces of oxygen. Since the growth of 

 the microorganisms is so abundant that the small amount of oxygen 

 present is rapidly used up, it can be assumed that the greater part of 

 their development takes place in the absence of free oxygen. Pasteur 

 has further shown that, in the case of yeasts, growth in the absence of 

 oxygen takes place only in the presence of sugar utilizable by these 

 organisms. Those organisms which are able to grow both in the pres- 



1 Pasteur, L. Animalcules infusoires vivant sans gaz oxygene libre et deter- 

 minant des fermentations. Compt. Rend. Acad. Sci. 52: 360. 1861; Experi- 

 ences et vues nouvelles sur la nature des fermentations. Ibid., 1260; 56 : 416, 1189- 

 1863; 75: 784. 1872; 80: 1875. 



PLATE X 

 Heterotrophic Aerobic and Anaerobic Bacteria 



50. Bac. mycoides, X 660 (from Conn). 



51. Bac. cereus, X 660 (from Conn). 



52. Bac. megatherium, X 660 (from Conn). 



53. Bac. simplex, X 660 (from Conn). 



54. Bad. vulgare, X 660 (after Omeliansky). 



55. Bad. pyocyaneum, X 660 (after Omeliansky). 



56. Bad. fluorescens, X 600 (after de Rossi). 



57. Bac. butyricus: a, non-spore forming; b, spore forming, X 660 (from 

 Omeliansky). 



58. Bac. sporogenes: a, 24 hour culture upon glucose bouillon; b, flagella, stained 

 by Loeffler's method (from Weinberg and Seguin). 



59. Bac. pulrificus, 48 hour old colony in deep glucose agar (from Weinberg and 

 Seguin). 



60. Bac.probatus: A, non-sporulating bacilli of a fresh agar culture; B, sporu- 

 lating bacilli of an agar culture 4-8 days old; C, spores with adhering membrane 

 of a 2 to 3 week old culture upon potato, X 1300 (after Viehoever and de Rossi). 



61. Sarcina ureae, X 660 (after Omeliansky). 



62. Bac. nitroxus, 3-day old culture, grown at 30°, X 480 (after Beijerinck and 

 Minkmann and de Rossi). 



63. Spirillum desulfuricans, X 660 (after Beijerinck and Omeliansky). 



160 



