532 RESPIRATION AND FERMENTATION 



Facultative anaerobes include : certain butyric bacteria (Granulobacter lacto- 

 butyricuni) and lactic bacteria (Sect. 103); a few nitrogen-producing bacteria 

 (Burri and Stutzer, I.e.); certain thermophile bacteria 1 , Bacillus phosphorescent 3 , 

 B. prodigiosus, B. typhi-abdominalis, Spirillum cholerae asiaticae, Proteus vulgaris 

 (Fliigge, I.e.). Granulobacter poly my xa and a certain form of Bacterium termo 

 are temporary anaerobes 3 , as are species of Saccharomyces. 



Obligate aerobes : among micro-organisms are Bacillus subtilis, B. cyanogenus, 

 B. aerophilus, Photobacterium lurninosum, P. indicum (Beyerinck, 1889, 1. c.), 

 Sarcina lutea. A trace of oxygen is required by sulphur-bacteria, and Saccharo- 

 myces mycoderma, 4 and red yeast are also obligate aerobes. 



SECTION 98. The Sources of Energy in Anaerobes (Respiratory 

 Katabolism continued). 



In anaerobes as in aerobes the relation between the amount of material 

 consumed and the crop produced varies according to the specific nature of 

 each organism and the prevailing external conditions, certain organisms 

 working more economically than others (Sect. 66). Thus some anaerobes 

 arc able to exist upon a small quantity of food-material without exhibiting 

 any marked fermentative activity, whereas in the case of yeast and the 

 bacteria of lactic and butyric fermentation, growth is necessarily accom- 

 panied by fermentative activity. Many, and perhaps most anaerobes, 

 arc able to grow without exciting fermentation and in many cases are 

 apparently entirely devoid of this power (Bacillus cholerae asiaticae, B. typhi, 

 B.polypiformis, &c.) 5 . Bacillus prodigiosiis can also develop without exciting 

 fermentation, although in the presence of sugar this power becomes manifest, 

 and similarly most anaerobes can be grown upon suitable media without 

 any fermentative activity being exhibited. 



The rate of growth bears no direct relationship to the amount of 

 kinetic energy liberated : thus in the absence of oxygen yeast finally ceases 

 to grow in spite of its continued fermentative activity and the marked 

 production of heat. Indeed growth may be inhibited with comparative 

 readiness although aerobic or anaerobic respiration may remain active 

 (Sect. 104). This may occur when an obligate anaerobe is exposed to 

 a trace of oxygen, while a facultative anaerobe may under special con- 

 ditions grow more actively in the presence of oxygen than in its absence, 



1 Rabinowitsch, Zeitschr. f. Hygiene, 1895, Bd. xx, p. 154. 



a Beyerinck, Le Bact. lumin., 1889, p. i (Sep.-abdr. a. Archiv. Neerland., T. XXIll). 

 8 Beyerinck, Centralbl. f. Bact., 1897, Abth. ii, Bd. in, p. 41. 

 * Beyerinck, ibid., 1895, Abth. i, Bd. I, p. 74. 



8 Cf. Liborius, Zeitschr. f. Hygiene, 1886, Bd. I, p. 172; Fliigge, Mikrborganismen, 1896, 

 3. Aufl., Bd. i, p. 127. 



