452 SUMMARY OF CURRENT RESEARCHES RELATING TO 



survived a longer exposure than 15 hours. The same was found to be- 

 the case with Streptococcus pyogenes, B. prodigiosus, B. proleus vulgaris, 

 B. pyocyaneus, B. typhosus, B. coll communis, B. mallei, B. pestis, B. 

 tuberculosis, the bacillus of Malta fever, and Spirillum cholera Asiatica. 

 Bacteria containing spores were more resistant, e.g. B. mesenterial^ 

 vulgatus, B. mesentericus ruber, B. subtilis, B. anthracis, B. tetani, 

 Gartner's bacillus, the bacillus of malignant oedema, and the bacillu; 

 of Rauschbrand. These were not killed by less than a 72 hours' ex- 

 posure. At 10 cm. distance the radium was found to have no 

 germicidal action. It was found that when micro-organisms have been 

 exposed to radium emanations for 24 to 120 hours, they themselves 

 may become radio-active. This induced radio-activity can be demon- 

 strated by bringing the bacteria so exposed in contact with a "rapid '" 

 photographic plate, and then developing the latter. 



Accumulation Experiments with Denitrifying Bacteria.* — G. van 

 Itersen, junior, by accumulation experiments {Anhdufungsversuche) 

 claims to have established a simple method for the isolation and culture 

 of denitrifying bacteria, obtained from earth, canal-water, horse-dung, 

 etc. His method is to introduce such material into a stoppered flask, 

 filled, to the exclusion of all air, with a solution of organic salts and 

 nitrate, to incubate for several days at 28° C, and then with the frothy 

 development so obtained to incubate a second flask filled with a similar 

 solution. When this has been repeated three times the last flask will be 

 found to contain practically a pure culture. In this way were isolated 

 B. Stutzeri (Neumann and Lehmann), B. denitrofluorescens sp. n., and 

 B. vulpinus sp. n. B. Stutzeri merits attention on account of the 

 characteristic form (a rosette) of its colonies on gelatin. B. denitro- 

 fluorescens is the first example of a fluorescent denitrifying non-liquefying 

 bacterium. B. vulpinus is chromogenic, but it requires light for the 

 development of its pigment. In the presence of free oxygen B. Stutzeri 

 and B. vulpinus behave as aerobic spirilla, and B. denitrofluorescens as 

 an ordinary aerobic bacterium. The denitrifying bacteria can themselves, 

 with the smallest quantities of many organic substances, bring about the 

 disappearance, in the form of free nitrogen, of estimated quantities of 

 nitrate. In the same earth in which nitrification can take place by 

 aeration, denitrification can take place by exclusion of air. 



Ferments of Diseases of Wines.f — P. Maze and P. Pacottet, in a 

 research on this subject, succeeded in isolating the ferments of la towns, 

 la graisse and Vamer. They used wines that had been for many years in 

 bottle, such being free from yeasts, fungi, and the common bacteria. 

 Such wine gave rise to no growth when inoculated in ordinary media, 

 aerobically. Anaerobic methods were therefore employed, and haricot 

 bouillon used as a culture medium. 1 ■ 2 c.c. of the deposit at the 

 bottom of the bottles was taken up into a Ronx's pipette with 15-20 c.c. 

 of haricot bouillon, containing 3 p.c. saccharose and * 2-0 " 3 p.c. tartaric 

 acid. After many weeks a whitish deposit appeared, which microscopic - 



* Verslagen der koninkl. Akad. van Wetensch. te. Amsterdam, xi. (1002-3) 

 biz. 135. See also Centralbl. Bakt., 2 ,e Abt., xii. (1904) pp. 106-15. 

 t Ann. Inst. Past,, xviii. (1904) pp. 244-63. 



