500 SUMMARY OF CURRENT RESEARCHES RELATING TO 



The bacteria dealt with were B. coli and B. enteritidis sporogenes, 

 which are specially abundant in contaminated water. B. coli was de- 

 tected in dilutions of 0-005 per cent., or 1 part of sewage in 20,000 

 parts of water, and B. enteritidis in a dilution of 1 in 500,000. 



Bacterial Treatment of Sewage. * — Dr. F. Clowes describes the 

 present aspect of the bacterial treatment of sewage in an article of great 

 clearness, which is illustrated by some effective photomicrographs of 

 sewage bacteria. A system which appears to give excellent results con- 

 sists in passing the sewage over coke beds after a preliminary treatment 

 in a septic tank, or, expressed, in other words, a preliminary anaero- 

 bic treatment is followed by intermittent aerobic treatment. In some 

 places the septic tank is not employed, and in others the sewage is 

 screened and sedimented previously, in order to prevent the beds from 

 choking. The coke-fragments are about the size of walnuts, and the 

 depth of beds 4-13 ft., the deeper bed giving the more satisfactory 

 results. In the beds, aerobic aud anaerobic organisms co-operate har- 

 moniously, but not necessarily cotemporaneously ; and, provided the beds 

 are not overworked, their purifying power increases with age. This is 

 in accord with the fact that new beds require to be primed in order to 

 give them a start. The effluent from beds worked on the intermittent 

 principle, i.e. allowing one day off in seven, is found to be clear and 

 odourless, and sufficiently purified to be introduced into the tidal part of 

 a river. 



Lactic Acid Bacteria found in Ripe Cheese.f — Herr G. Leichmann 

 and Herr S. v. Bazarewski examined bacteriologically samples of Em- 

 menthal, Cheshire, and Gouda cheeses, and describe five species of bacteria, 

 the plate colonies of which presented the appearance of Bacterium Jactis 

 acidi Leichmann. Microscopical examination of milk cultures showed, 

 however, that they were quite different. Four of these bacteria are de- 

 signated Bact. casei i., ii., iii., iv., and the fifth Streptococcus casei. The 

 morphological and physiological characters are described at considerable 

 length, and the differences between this group, Bact. lactis acidi, and 

 Bact. pabali acidi i. and ii. and others are discussed. 



Gonotoxin. J — Dr. J. De Christmas, who has been studying the toxin 

 of Gonococcus, finds that when cultivated in appropriate media the 

 microbe produces toxic substances which, when introduced even in small 

 doses into the brain, rapidly cause death with the phenomena of intoxi 

 cation. The toxin is dissolved in the medium. It is a biological pro- 

 duct, and is formed only under certain determinate conditions of culture, 

 and is not diffused from the bodies of dead gonococci. It is not dia- 

 lysable; it resists heating to 60° for at least one hour; but when heated 

 to 75° for 15 minutes it begins to change. It is precipitated from the 

 culture by saturated solution of sulphate of ammonia. When injected 

 into the subcutaneous tissue of laboratory animals, an antitoxin is pro- 

 duced in the blood. This antitoxin neutralises in vitro the gonococcic 

 toxin, and when injected into the brain before the toxin, the phenomena 

 of intoxication are inhibited. It has the same effect Avhen injected into 

 the blood-vascular system. 



* Nature, lxii. (1900) pp. 128-32 (9 figs.). 



t Centralbl. Bakt. u. Par., 2 M Abt., vi. (1900) pp. 245 53, 281-5, 314-31. 



t Ann. Inst. Pasteur, xiv. (1900) pp. 331-49. 



