■276 Decomposition of Organic Compounds. 



collected and transferred to a condenser. Since C0 2 is the only gas liberated 

 in alcoholic fermentation there is assumed to be no oxidation of the 

 platinum electrodes. The charge, as measured by a ballistic galvanometer, 

 was found to correspond to an E.M.F. of 0-3 to 0-5 volt between the 

 fermenting and non-fermenting fluids. A difference of potential also occurs 

 ■during hydrolysis, either by enzymes or by weak acids. 



Various metallic electrodes can be used in conjunction with a condenser for 

 the estimation of the E.M.F. produced. Non-polarisable electrodes, however, 

 give no voltage with a condenser and are unsuitable for this method. 

 Distinct electric currents are found whichever form of electrode is used. 



The electrical effects are an expression of the activity of the micro- 

 organisms and are influenced by temperature, concentration of the nutrient 

 medium, and the number of active organisms present. These effects are only 

 found within the limits of temperature suitable to the micro-organisms and 

 under conditions which are favourable to protoplasmic activity. 



The maximum voltage recorded was 0-3 to 05 volt, and a voltage of this 

 order was never exceeded in any of the experiments undertaken with micro- 

 organisms. 



LITEEATUEE. 



Haacke, O. "TJeber die Ursachen electrischer Strome in Pflanzen," 'Flora,' 1892, 

 vol. 75. 



Klein. B. "Zur Frage iiber die elektrischen Strome in Pflanzen," 'Berichte der 

 Deutschen Botanischen Gesellschaft,' 1898, vol. 16. 



Potter, M. C. "On the Difference of Potential due to the Vital Activity of Micro- 

 organisms,' 'Durham Univ. Phil. Soc. Proc.,' 1910, vol. 3. 



Waller, A. D. 'The Signs of Life,' 1903 ; 'Californian Lectures/ 1910. 



