io6 BACTERIAL ASSOCIATIONS 



because of its active fermentation. Filtrates had no effect. These changes they be- 

 lieved were due to a synergism between B. putrificus and certain aerobes. B. coli 

 either helped the bilirubin production or hindered it, depending on the presence or 

 absence of fermentable material. They further demonstrated the development of hem- 

 atoporphyrin from blood by a similar synergism and that sugar or bile inhibited it. 

 A particularly important instance of bacterial association was reported by Speakman 

 and Phillips.' During the war, acetone and butyl alcohol were produced on a large 

 scale by fermentation of cereals and carbohydrates. Serious difficulties developed in 

 the plants, owing to the contamination of the cultures of B. granulohacter-pectin- 

 ovorum by the aerobic bacillus B. volutans. The acetone yield, as a result of the 

 mixed culture, dropped or disappeared and the development of lactic acid increased. 

 This increase was due to an altered metabolism of the acetone producer so that it 

 formed more lactic acid and less acetone. The results varied with the relative numbers 

 of each organism present. They considered it due to an inhibitory substance from the 

 nitrogen metabolism. In actinomycotic granules there is found a bacterium named 

 by Klinger^ B. actinomycetum coniitans, the presence of which was confirmed by 

 Colebrook^ in 80 per cent of his twenty cases. The significance of this associate is 

 not known, but Colebrook suggested a possible genetic relationship. There are many 

 other examples of anaerobic and aerobic associations in the natural metabolism of 

 the sulphur bacteria; in silage fermentation, the heat of which was definitely shown 

 by Hunter'' to be due to bacterial action and not to cell respiration; in sewage decom- 

 position and cellulose destruction in which Groenewege^ believed a symbiosis occurred 

 but stressed the action of the aerobes and Khouvine*" gave chief importance to a 

 strict anaerobe discovered by him, B. cellulosae dissolvens (n.sp.), but pointed out 

 that five times as much cellulose was de5tro3'ed when in association as when alone. 

 There are other examples in the natural breakdown of organic materials of all kind 3 

 and in innumerable other bacterial activities in nature. 



THE ACroURIC GROUP (aND CERTAIN THERAPEUTIC USES) 



The effects of the aciduric group of bacteria on other bacteria has been closely 

 Studied. They are usually facultative aerobes, and their action is considered as chief- 

 ly antagonistic. Because of their use for therapeutic purposes there has collected an 

 extensive literature brought together by Rettger and ChepHn^ and Kopeloff.* Certain 

 points, however, may be briefly reviewed. Starting from the work of Metchnikoff 

 with B. bulgariciis it was soon found that this organism could not be implanted in ih^ 

 intestinal tract and B. acidophilus, a normal inhabitant, was substituted. B. bijidus 



' Speakman, H. B., and Phillips, J. F.: /. Bad., 9, 183. 1924. 

 » Klinger, R.: Centralbl.f. BaktcrioL, I, Orig., 62, 191. 1912. 

 3 Colebrook, L.: Brit. J. Expcr. Path., 1, 107. 1920. 

 ••Hunter, O. W.: /. Agric. Research, 10, 75. 1917. 

 s Groenewege, J.: reference in J .A.M. A., 76, 279. 1921. 



* Khouvine, Y.: Ann. de Vlnst. Pasteur, 37, 711. 1923. 



7 Rettger, L. F., and Cheplin, H. A. : The Intestinal Flora with Special Reference to the Implantation 

 of "Bacillus acidophilus." Yale University Press, 1921. 



* Kopeloff, N.: "Lactobacillus acidophilus." Williams & W'ilkins Co., 1926. 



