FERMENTATION BACTERIOLOGY. 813 



Fixation of atmospheric nitrogen by dead leaves, L. D£trie (Bui. Soc. Cent. 

 Forst. Belg., 5 {1898), No. l,pp. 36-38). 



The proteolytic enzym of Nepenthes, S. H. Vines (Ann. Bot., 11 (1897), No. 44, 

 pp. 563-584). — The author believes the proteolytic digestion which takes place in 

 pitcher plants is due to an enzyrn and not to bacteria. In Nepenthes he found tbat 

 fibrin was digested in the presence of 1 per cent of hydrocyanic acid and that the 

 activity of the ferment is retained for several weeks in pure glycerin. 



A new bigeneric hybrid, S. Korsiiixskv (Bid. Acad. Impe'r. Sci. [St. Peter sbourg], 

 5. set-., 6 (1897), No. 4, pp. 322-324, pi. 1).—A. hybrid of Citciimis melo and Citrullus 

 vulgaris is described. 



FERMENTATION— BACTERIOLOGY. 



The bacteriological flora of the air in stables, A. W. Bitting 

 and C. E. Davis (Proc. Indiana Acad. Sci., 1896, pp. 172-184, ph. 5).— 

 The authors report studies conducted to determine the number of bac- 

 teria found in the air of stables, and to determine whether a relation- 

 ship exists between the number of germs found in air and the sanitary 

 condition of the place. Ten barns and stables were selected, represent- 

 ing different sanitary conditions, and 15 tests of the air were made 

 inside the buildings and a corresponding number in the open air at the 

 same time. The average number of colonies developed per liter from 

 the air inside the stables was 80, as compared with 27 from the outside 

 air. Thirty tests were made by Petri dish exposures for 2 minutes 

 each in the air inside the stables and 15 tests in the open air. The 

 average number of colonies on the plates exposed inside the stables was 

 174, and 55 on those exposed outside. 



It was found tbat the number of germs per liter of air could not be 

 taken as an index of the sanitary surroundings, as the dust caused by 

 feeding, moving of bedding, currying, etc., have more to do with the 

 number of germs which will be drawn into a Hesse tube or fall on a 

 Petri dish than lack of ventilation has. 



Detailed descriptions are given of 18 forms of bacteria collected in 

 the different stables. 



Studies on nitrification, II. Weissenberg ( Arch. Hyg., 30 (1897), 

 Fo. 3, pp. 274-289; abs. in Chem. Ztg., 21 (1897), Wo. 85, Repcrt., p. 231).— 

 Studies of the Bacillus denitrificans I and II of Stutzer and Burri, or, 

 adopting the nomenclature of Lehmann and Neumann, B. denitrificans 

 and B. stutzeri, were made under varying conditions in different culture 

 media. It appears from these studies that, as Stutzer and Burri claim, 

 the first of these organisms denitrifies only when acting in symbiosis 

 with other organisms which reduce nitrates to nitrites, such as Bacillus 

 coli or B. typhi. The second organism, B. stutzeri, in comparative tests 

 with B. pyocyaneum from different sources behaved like the latter in 

 every case, denitrifying nitrates directly without the intervention of 

 other organisms. In the reduction of the nitrates the oxygen is seized 

 by the organism, the nitrogen escapes, and sodium hydroxid is 

 formed, increasing the alkalinity of the medium. This process is 

 checked by the introduction of a liberal supply of air (oxygen). In 



