IVAN C. HALL 203 



Among the micro-aerophilic aerobes are Bad. abortus (Bang),' the fowl diphtheria 

 organism of Miiller,^ and certain pyogenic streptococci of Graf and Wittneben.^ Rose- 

 now* beUeves that his success in cultivating streptococci with selective pathogenicity 

 depends upon varying oxygen pressures. Wherry and his associates^ have concluded 

 from experiments with the gonococcus, Entameha buccalis, Leptoihrix innominata, 

 C. diphtheriae, and M. tuberculosis, that reduced oxygen tension is more important in 

 disease processes than is ordinarily supposed. A slight reduction facilitates the growth 

 of the meningococcus according to Cohen and Markle,^ and Cohen and Fleming^ have 

 stated that the optimum is represented by an atmosphere of 10 per cent CO2 and 90 

 per cent air. But Kohman* has shown that the buffer action of CO2 is more important 

 than the slight reduction of oxygen tension, and this viewpoint has been extended to 

 other species by Rockwell and his collaborators,' who have shown that carbon dioxide 

 is necessary for the growth, not only of many aerobic but also several obligately an- 

 aerobic bacteria. 



While some organisms are favored by decreased oxygen, Moore and Williams"* 

 found that many aerobic bacteria may be cultivated in nearly pure oxygen. But al- 

 though M. tuberculosis and B. pestis were apparently oxyphobic, being completely 

 inhibited by 80-90 per cent of this gas, yet Novy and Soule" have demonstrated that 

 M. tuberculosis grows readily in concentrated oxygen if sufficient moisture be pro- 

 vided. 



The physico-chemical conception holds that obligate anaerobes differ from the 

 aerobes by the fact that small amounts of oxygen are inhibitive to their growth and 

 toxic to their protoplasm. It is the toxicity of the oxygen which in practical usage 

 separates them from the aerobes by their failure to grow on the slanted surface of 

 solid media exposed to the air through the cotton plug of a culture tube, 



BIOLOGICAL THEORIES OF ANAEROBIOSIS 



Aerobe-anaerobe symbiosis. — The remarkable fact that obligately anaerobic bacte- 

 ria occur abundantly in soil, water, and decaying substances, apparently in contact 

 with the oxygen of the air, was perhaps first correctly explained by Pasteur" on the 



' MacNeal, W. J., and Kerr, J. C: /. Infect. Dis., 7, 469. 1910. 



* Miiller, R.: Centralbl.f. Bakteriol., Abt. I, Orig., 41, 515 and 621. 1906. 

 3 Graf, H., and Wittneben, W.: ibid., 44, 97. 1907. 



4Rosenow, E. C: J. A.M. A., 65, 1687. 1915; /. Infect. Dis., 32, 41, 72, 144, 384. 1923. 

 s Wherry, W. B., and Oliver, W. W.: J. Infect. Dis., 19, 288, 299. 1916; 20, 28. 1917; Wherry, 

 W. B., and Ervin, D. M.: ibid., 22, 194. 1918; Wherry, W. B., and Ray, V.: ibid., p. 554. 1918. 



* Cohen, M. B., and Markle, L.: J. A.M. A., 67, 1302. 1916. 

 'Cohen, M. B., and Fleming, J. S.: /. Infect. Dis., 23, 337. 1918. 

 'Kohman, E. F.: J. Bad., 4, 571. 1919. 



'Rockwell, G. E., and collaborators: J. Infect. Dis., 28, 249 and 352. 1921; 32, 98. 1923; 35 

 581. 1924; 38, 92. 1926. 



'"Moore, B., and Williams, R. S.: Biochem. J., 4, 177. 1909; s, 181. 1910; Brit. M. J., 2, 873. 

 1909. 



" Novy, F. G., and Soule, M. H.: /. Infect. Dis., 36, 168. 1925. 



" Pasteur, L.: Compt. rend. Acad, de sc, 56, 416-1192. 1863. 



