VARIOUS BACTERIA 



126 



TABLE 24 

 Electrode Potentials in Cultures of Members of Salmonella Group (Eh in volts) 



Burrows and Jordan have attempted to fit an equation of the y = ax -f b type 

 to these curves of potential drift, but, beyond stating that the different species 

 behave differently, little more can be expected from a mathematical analysis of 

 systems containing so many variable factors. 



B. megatherium. — Knaysi and Dutky (1934) and Wood, Wood and Baldwin 

 (1935) present different evidence upon the effect of electrode potentials on the 

 initiation of growth of this organism. 



Anaerobes. 



The factors concerned in anaerobic growth have already been discussed in 

 general terms. 



CI. welchii and CI. tetani. — Lepper and Martin (1930) found that a low level of 

 potential was attained by these organisms in media containing meat. In the latter 

 case, at any rate, gas formation (hydrogen) did not account for the low potential 

 reached. Plotz and Geloso (1930), Fildes (1929), and Knight and Fildes (1930) 

 have investigated the upper limit of potential inhibiting the proliferation of CI. tetani 

 and its spores. 



CI. hotulinum and CI. sporogenes. — Plotz and Geloso (1930) described the low 

 level of potential attained in cultures of these organisms. (See also Hanke and 

 Bailey, 1945.) 



Non-sporulating anaerobes. — In cultures of those anaerobic bacteria which do not 

 form spores, a very wide range of potentials is reached. (Dack and Burrows, 1935.) 



B. saccJmrobutylicus. — From observations on an anaerobic strain of the butyric 

 acid bacillus it was concluded by Messing (1934) that the growth of this anaerobe 

 is dependent upon the metabolic activities of the organism, and not solely upon the 

 electrode potential of the culture medium. 



M. lysodeiliticus. — This aerobe was found to grow more readily and even attain 

 more intense reducing potentials when the culture was vigorously aerated. Some fall 

 of potential was otssrved when the organisms were lysed by addition of lysozyme 

 (Hewitt, 1931.) 



B. subtilis and B. mycoides. — These were examined by Gillespie (1920) but were 

 not found to attain the low levels of potential reached by soil organisms. The slow 

 fall in potential of B. subtilis cultures was observed also by Cannan, Cohen and Clark 

 (1926). 



