756 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Luminous Bacteria.* — J. E. Barnard and Allan Macfadyen have 

 studied these organisms, chiefly marine. They advocate the addition of 

 3 p.c. NaCl to the culture media. This favours luminosity, which appears 

 to be essentially a vital phenomenon. Dead cells are non-luminous. A 

 supply of free oxygen is necessary, for the luminosity, though not for 

 the life of the cell. Exposure to low temperature — that of liquid air — 

 did not destroy the luminosity of the organism. 



The Bactericidal Action of some Ultra-Violet Radiations as 

 produced by the Continuous-Current Arc.f — J. E. Barnard and H. de 



R. Morgan experimented to determine the effect on the vitality of 

 certain bacteria of exposure to the arc spectra of carbon and of various 

 metals. The spectrum was projected on to an agar film, contained in 

 an ordinary Petri dish, over the surface of which had been spread with 

 a sterilised brush an active culture of the organism. The plates were 

 exposed to the light directly after inoculation, and were then incubated 

 for 24 hours at 37° C. It was found that the bactericidal action was 

 entirely confined to the ultra-violet region. The active radiations lie 

 in that portion of the spectrum between the wave-lengths 3287 and 

 2265. Neither the extreme ultra-violet rays nor those nearest to the 

 visible violet appeared to be active. 



Experiments were also made with hanging-drop preparations, when 

 with the distance of the arc from the drop at 10 cm., and the current 

 used 11 amperes, the organisms were killed in from 15-30 minutes, 

 according to the metal employed. 



Agglutination by Blood of Emulsions of Microbes, with special 

 reference to Specificity .J— E. Klein found that the blood of different 

 typhoid cases varied in agglutinating power. He failed to obtain 

 agglutination by typhoid blood of any of the varieties of B. coli isolated 

 by him from typhoid stools, or of B. coli communis obtained from 

 various other sources. He found that typhoid blood had an agglu- 

 tinating reaction on the Gartner bacillus and on the Danysz rat bacillus, 

 though this was less than the reaction of the same blood on B. typhosus. 

 Experimenting with the blood of " Danysz-immunised " guinea-pigs, 

 the author found that it had the power of agglutinating B. typhosus, 

 as well as Gartner and Danysz. A like result was obtained with the 

 blood of " Gartner-immunised " guinea-pigs. 



La Garotilha.— E. Marchoux and A. Salimbeni,§— following Chapot- 

 Prevost, and Gomez and Terni — have demonstrated that the disease of 

 cattle known in Brazil as la Garotilha is anthrax, and they believe that 

 the vultures so numerous in that country are responsible for its spread. 

 They fed one of these birds on an infected guinea-pig, and readily 

 isolated the B. anthracis from the excreta. 



Researches on the Fermentation of Milk. — H. Tissier and E. 

 Gasching (] kept samples of milk under observation for 8 to 10 months. 



* Kep. Brit. Assoc, 1902, p. 801. 



+ Proc. Roy. Soc, lxxii. (1903) pp. 126-8. 



% Rep. Med. Off. Local Gov. Board, l'JOl-2, pp. 440-54. 



§ Ann. Inst. Pasteur, xvii. (1903) pp. 564-8. 



II To-n. cit, pp. 540-63. 



