62 Mr. A. G. R. Foulerton and Dr. A. M. Kellas. [Mar. 30, 



The current being discharged over the emulsion from the brush, it was 

 conducted away by means of a short length of platinum wire which was 

 sealed through the bottom of the test-tube and dipped into a layer of 

 mercury -at the bottom of a beaker of water in which the test-tube was 

 suspended for cooling purposes, the level of the water in the beaker being 

 kept well above the level of the bacterial emulsion in the test-tube. From 

 the layer of mercury in the beaker an " earth wire " passed to a gas supply 

 pipe. 



In some of the experiments carried out with this arrangement of 

 apparatus the cooling beaker was not used, and the electrical current was 

 allowed to escape into the air as a brush discharge from the platinum wire 

 which passed through the bottom of the test-tube. 



(&) In another set of experiments there was a layer of mercury at the 

 bottom of the bacterial emulsion in the test-tube, but no wire passing from 

 the tube. In these experiments the results were not satisfactory, for the 

 current appeared to diffuse in various directions after its discharge, and 

 apparently but a small proportion of it passed through the emulsion. 



(c) In another type of tube which was used, a cap of tin foil encapsuling 

 the lower end of the tube was substituted for the length of platinum wire 

 passing through the bottom of the tube ; a few turns of copper wire were 

 wound round this metal cap, and the efferent end of the wire was attached 

 to a gas pipe. This type of tube also was found to give unsatisfactory 

 results ; when using it the current seemed to discharge itself chiefly towards 

 the side of the glass tube at the upper level of the emulsion and then to 

 pass down the side of the tube to the metal cap without passing through the 

 emulsion itself. 



In the experiments detailed in what follows it is to be understood that the 

 arrangement for conducting the current after its discharge above the 

 emulsion was that described under (a), and, unless the contrary is stated, 

 the platinum disc brush was used. The arrangements described under (b) 

 and (c) are mentioned for the reason that the apparently different course of 

 the current subsequent to discharge which was observed with their use 

 served to confirm our opinion that with the use of arrangement (a) the 

 current after its discharge did actually pass directly through the emulsion. 



For the course of these experiments it seemed probable that the bacterial 

 emulsion was subjected to the influence of two factors : first there was the 

 action of the discharge on the surface from the platinum brush, and then 

 there was the action of such part of the current, if any, which subsequently 

 passed through the fluid. 



And as it appeared to us that the passage of a maximum portion of the 



