W. L. HOLM AN 115 



a diseased cow, but gave typical results after injection of the cultures isolated from 

 the soil. I have collected the literature on this subject, but it will not be included here. 

 The explanation of the results rests largely on the fact that the anthrax spores are 

 phagocyted by the leukocytes attracted to the site of injection by the other bacteria 

 before they start developing and then are destroyed or eliminated. A most important 

 discussion on the principles of such infections may be found in an article by Bail.' 



GAS SYNERGISM 



Holman and Meekison^ reported certain findings in gas production by bacterial 

 synergism and have reviewed the literature on this phase of bacterial association and 

 attempted to show that inhibition and stimulation are both based on the combined 

 metabolism of the bacteria in the mixtures and that the same bacterium may use 

 various methods in acting on the substances offered, depending on the environment. 

 Sears and Putnam-' and Castellani^ have given many instances of its occurrence. 

 Castellani has further discussed the whole subject of close association of different 

 species and particularly its importance in the causation of certain diseases and their 

 symptoms. He does not, however, review the literature. 



ALTERATION BY ASSOCIATION 



Dissociation of bacteria has been gradually attracting more and more attention, 

 and since bacterial association is so important to appreciate the analysis of the re- 

 sults obtained, a word or two may be added here. I have already given a number of 

 examples of important alterations in the biochemical activities of certain bacteria 

 living in association with others. Sometimes such changes were lasting on transfer, 

 at other times fleeting. Rosenow^ claimed that he was able to change a hemolytic 

 streptococcus to the viridans type by growth in symbiosis with B. subtilis. This P 

 was unable to confirm, and I have reviewed the literature on the longevity of strepto- 

 cocci in symbiosis and have shown the many chances of error from mixed cultures, 

 particularly with closely similar forms, Pneumococci may live in intimate contact 

 with non-hemolytic streptococci for long periods, and the demonstration by Alivi- 

 satos' of the occurrence of mixed colonies of streptococci with staphylococci gives ad- 

 ditional weight to the importance of such sources of error. The more sensitive organism 

 will die out first, and retests may give quite different results from those found with 

 the mixture. This danger was also emphasized by us^ for the gram-negative group 

 of aerobic intestinal bacteria. Nevertheless, bacteria are living, reactive beings and 

 as such are subject to alterations of many kinds. Bail' has shown how important this 

 is in the infectiousness of bacteria (the change to the so-called "animal form"), and 



'Bail, O.: Ztschr. des. ges. Expcr. Med., 50, 11. 1926. 

 ^Holman, W. L., and Meekison, D. M.: loc. cit. 

 3 Sears, H. J., and Putnam, J. J.: /. Infect. Dis., 32, 270. 1923. 



■• Castellani, A.: Brit. M. J., 2, 734. 1925; Proc. Soc. E.xper. Biol. & Med., 23, 481. 1926; 

 J.A.M.A., 87, 15. 1926. 



5 Rosenow, E. C: /. Infect. Dis., 14, i. 1914. 



* Holman, W. L.: ibid., 15, 293. 1914. . * Holman, W. L., and Meekison, D. M.: loc. cit. 



' Alivisatos, G. P.: loc. cit. » Bail, O.: loc. cit. 



