I04 BACTERIAL ASSOCIATIONS 



dered sublethal doses of this anaerobe fatal for rabbits, and he himself found that the 

 injection into guinea pigs of B. proteus and his new anaerobe {B. oedcmatiens) resulted 

 in rapid death and an enormous growth of the anaerobe in the animal body. The 

 overgrowth was absent with pure cultures. He further was able, by adding B. proteus 

 and other aerobes, to grow his anaerobe in the presence of air. Passing over numer- 

 ous similar results we find Sturges' devising a method, based on bacterial association, 

 for isolating spore-bearing anaerobes on open plates by growing them with B. coli 

 or Staphylococcus aureus. Rhein^ used B. fecalis alcaligenes in bouillon for anaerobic 

 growth because of the lack of saccharolytic and proteolytic activity in this aerobe. 

 Inoculation of the mixed cultures into animals he considered practical because the 

 aerobe is not toxic, but I believe from the work of many others that this procedure 

 might well give faulty results. Barrieu^ noted that B. proteus and certain non-patho- 

 genic spore-bearing aerobes found in wounds exalted, by their proteolytic activity, 

 the virulence of pathogenic bacteria. Pringsheim^ grew Frankel's bacillus {B. welchii) 

 with B. fecalis alcaligenes for ten transfers on agar slants and could see in the growth 

 of the latter the opaque colonies of the anaerobe, A hquefying sarcina allowed B. 

 welchii and B. hutyricus to grow in open tubes. After six days' growth the sarcina had 

 disappeared from the B. butyricus culture, and he suggested this as an easy method 

 to obtain a pure culture. Weinberg and Otelesco^ considered that many war-wound 

 infections, looked upon as of pure anaerobic origin, may be due to an association with 

 B. proteus since this latter organism increased the virulence of B. perfringens, V . 

 septique, and others. Animals injected with B. sporogenes and B. proteus did not de- 

 velop putrid lesions. This combined growth of aerobes and anaerobes on surface cul- 

 tures I observed on a number of occasions in France while studying the bacterial flora 

 of war wounds. Colonies picked from aerobic plates were not infrequently found to 

 be mixed with anaerobes. 



Stillman and Bourn^ reported in 1920 the production of gas by 16 of 119 non- 

 hemolytic strains of B. influenzae in i per cent dextrose agar with a little blood ex- 

 tract. Four of 29 hemolytic strains also produced gas. Jordan and Reith^ also found 

 gas production in certain of their strains. About four years ago, when working with 

 cultures of a tiny anaerobe resembling B. pneumosintes^ (probably Staphylococcus 

 parvulus of Veillon and Zuber), I mixed a culture of this anaerobe with a culture of 

 B. influenzae and planted the mixture on blood-agar slants. A good growth of B. in- 

 fluenzae occurred, and after five transfers I had no difficulty in recovering the gas- 

 producing anaerobe in cooked-meat media. This anaerobe is practically always present 

 in the oral cavity, and could easily contaminate cultures of B. influenzae. It can be 



' Sturges, Jr., W. S.: Ahslr. Bad., i, 63. 1917. 



^ Rhein, M.: Prcsse mcd., 27, 504. 1919. 



3 Barrieu, A. R.: ibid., 28, 40. 1920. 



"I Pringsheim, E. G.: Ccnlralbl. f. Bakleriol., II, 51, 72. 1920. 



5 Weinberg, M. and Otelesco, I.: Compl. rend. Soc. de biol., 84, 535. 1921. 



* Stillman, K. G., and Bourn, J. M.: /. Exper. Med., 32, 665. 1920. 



7 Jordan, E. O., and Reith, A. F.: 7. Infect. Dis., 34, 239. 1924. 



8 Holman, W. L.: .im. J. Ilyg., 3, 4S7. 1923. 



