BACTERIA DECOMPOSING UREA 211 



urea at low temperatures, even below 0°C, were isolated from water and 

 curative muds. 15 



Bacteria decomposing calcium cyanamide. Calcium cyanamide is 

 decomposed with the formation of ammonia by Bad. erythrogenes, 

 Bart, kirchneri as well as other non-spore-forming bacteria present in 

 the soil. 16 For the isolation of the organisms, the following media can 

 be used: meat peptone gelatin, soil extract gelatin (10 per cent gelatin, 

 reaction alkaline) or cyanamide solution with the addition of 10 per cent 

 gelatin, then made alkaline after boiling. Certain bacteria can use 

 dicyandiamide as a source of nitrogen, in the presence of glucose. The 

 amide, however, is decomposed to a very inappreciable extent and no 

 ammonia is formed. 17 



Uric and hippuric acid bacteria. Uric acid, which is an important 

 constituent of the manure of birds and snakes and is also present to 

 a slight extent in the urine of mammals, is also decomposed by bacteria, 

 urea being the chief product. 18 A solution of uric acid inoculated with 

 putrid urine was found to be completely decomposed in a few days to 

 ammonium carbonate with the formation of CC>2. 19 When the process 

 was interrupted before the uric acid was completely decomposed, urea 

 could be demonstrated. Bart, ureae and Bart, fluorescens were found to 

 be responsible for the process. Gerard 20 found that the decomposition 

 of uric acid goes on in two stages. The uric acid is first decomposed 

 into urea and tartronic acid, the urea is then hydrolized to ammonium 

 carbonate. Ulpiani and Cingolani 21 isolated from chicken excreta an 

 aerobic, motile, slime-forming streptococcus, not producing any spores 



15 Rubentschik, L. Tiber die Lebenstiitigkeit der Urobakterien bei einer 

 Temperatur unter 0°C. Centrbl. Bakt. II, 64: 116-174. 1925; 66: 161-180. 

 1926. 



16 Lohnis, F., and Sabashnikoff, A. Ueber die Zersetzung von Kalkstickstoff 

 und Stickstoffkalk. II. Centrbl. Bakt. II, 20: 322-332. 1908. 



17 Perotti, R. Uber die Dicyandiamidbakterien. Centrbl. Bakt. II, 21: 

 200-231. 1908. 



18 Lex, R. Uber Fermentwirkungen der Bakterien. Centrbl. Med. Wiss. 10: 

 292, 513. 1872. 



19 Sestini, F. and L. Tiber die ammoniakalische Garung der Harnsiiure. 

 Landw. Vers. Sta. 38: 157-164. 1890. 



20 Gerard, E. Fermentation de l'acide urique par les microorganismes. 

 Compt. Rend. Acad. Sci. 122: 1019-1022. 1896; 123: 185-187. 



21 Ulpiani, C. Uber das Bakterium der Harnsaure. Cingolani, M. Chem- 

 ische Gleichung der Garung der Harnsiiure. Ref. Chem. Centrbl. 2: 1287. 1903; 

 Gaz. Chim. Ital. II, 33: 93-98, 98-124. 1903; Atti Roy. Accad. Lincei, Roma, 

 (5) II. 12: 236-240. 1903. 



