1911.] Decomposition of Organic Compounds. 



275 



Other Electrodes. — Although platinum wires were employed as the standard 

 electrodes throughout this investigation, trials were also made with other 

 metallic wires such as gold, nickel, tin, zinc, and aluminium. All these 

 metals when used as electrodes, as well as carbon plates from Leclanche" cells, 

 showed the existence of a difference of potential between the yeast-glucose 

 solution and the glucose solution, and also the existence of an electric current 

 passing in the cell from the yeast-glucose to the glucose. The amount of the 

 E.M.F., however, was found to vary with the different electrodes used ; but 

 an inquiry into the causes of this variation leads into the domain of physical 

 chemistry and lies outside the scope of the present investigation. 



It may be mentioned that a battery of six cells with carbon electrodes 

 connected in parallel gave a current of T25 milliampere. 



In this preliminary investigation only commercial yeast of the kind 

 known as " German yeast " was used, and at present no experiments have 

 been made with pure cultures of the different races of Saccharomyces. So far 

 cane sugar and ordinary glucose dissolved in distilled water have provided the 

 nutrient media for the yeast, but evidence is not wanting that very slight 

 differences in chemical composition directly affect the character of the results 

 obtained. Enough has been done to show that this electrical method may be 

 conveniently utilised to study the vital activity of yeast and other organisms 

 when growing under special cultural conditions. It will be a matter of 

 interest to compare the E.M.F. produced by the different races of 

 Saccharomyces in the various kinds of sugars, and also to study the effect of 

 inorganic salts, such as phosphates, nitrates, &c. To follow up the question 

 as it affects enzymes opens up a large field of work, and this subject presents 

 a problem in itself. The action of bacteria in producing electrical effects also- 

 awaits more detailed investigation. 



I desire to express my thanks to Dr. A. D. "Waller for the interest he has 

 shown in this research and for the opportunity he kindly afforded me of 

 repeating my results in the Physiological Laboratory of the University of 

 London. My thanks are also due to Dr. W. M. Thornton for the kind help 

 he has given me in the revision of the proofs. 



Summary and Conclusions. 



The disintegration of organic compounds by micro-organisms is accompanied 

 by the liberation of electical energy. 



The difference of potential was investigated by the employment of a 

 special type of galvanic cell with platinum electrodes, by means of which the 

 electrical charges set free in the vital processes of the micro-organisms were- 



