12 Action o/B cloacse (Jordan) on Citric and Malic Acids. 



(d) Citric acid is decomposed by B. cloacce in the presence of oxygen into 

 the same products as malic acid. 



The values found for the respiratory coefficient and for the molecular 

 ratio CO2/C2H4O2 are intermediate between those required for the following 

 equations : — 



(2) 4C 6 H 8 7 + 40 2 = 7C 2 H 4 O 2 + 10CO 2 +2H 2 O. 



(3) 4C 6 H 8 7 + 2H 2 + 20 2 = 8C 2 H 4 2 + 8C0 2 + 2H 2 0. 



This is probably due to the difficulty of maintaining complete aeration of 

 the medium during the experiment, the decomposition being therefore partly 

 anaerobic and partly aerobic in character. 



(e) It is possible that the decomposition of citric acid by B. cloacae, takes 

 place in the same way in the presence or absence of oxygen, according to 

 equation (1), but that in the presence of oxygen a variable portion of the 

 acetic acid is subsequently oxidised. 



(/) Methylacetylcarbinol, which is produced by the action of B. cloacce on 

 mannitol and glucose, is not formed in the fermentation of malic acid or of 

 citric acid by this organism. 



REFERENCES. 



1. O. Emmerling, 'Ber.,' 1899, vol. 32, p. 1915. 



2. Bosworth and Prucha, ' Journ. Biol. Chem.,' 1911, vol. 8, p. 479. 



3. Thompson, 'Roy. Soc. Proc.,' 1912, B, vol. 84, p. 500. 



4. G. Ritter, < Central, fur Bakt., II,' 1907, vol. 20, p. 21. 



