360 BOTANICAL GAZETTE [NOVEMBER 
usual bacterial methods were employed throughout these tests. All 
platings were made in Petri dishes in standard agar-agar, and the usual 
dilution methods were followed. The agar cultures were incubated 
at the usual temperatures, but the experiments were conducted at 
room temperatures in most cases, which ranged from 60° to 70° F." 
TABLE I 
Showing the influence of electrical stimulation (galvanic currents) on the bacteria 
in water. First cultures made 24 hours after treatment. 
NUMBER OF BACTERIA IN 1°° 
DATE OF MAKING 
ULTURE 
Normal | Trested 
June TO Vis fas GA0Z 43,642 
BO es 3435 108,785 
The experiment shown in the preceding table was made with 
two rectangular jars with approximately 
the following interior dimensions: height 
16°™, width 12°™, diameter 4°™. These 
jars were filled with water obtained from 
a pond contaminated to a greater or less 
extent with sewerage. One was a normal 
or untreated jar, and the other contained 
electrodes composed of copper and zinc 
respectively, which were connected with 
wires and generated a current. The 
electrodes were of the same diameter 
as the jar, and one was placed in each 
end. A jar of this type constitutes 4 
galvanic element (water cell), although 
the strength of current produced in this 
Fic. 1.—Jar, ieondal with case is very weak, averaging about 0.1 
cotton ohag and copper and zinc milliamperes. Samples of the water were 
electrodes, used i in electrical ex- plated i in agar-agar 24 hours after treat- 
periments with milk and water. ment. On the second day, however, the 
experiment was discontinued. The results given in table I show 
In carrying on these experiments the writer is under special obligation to Mr. 
N. F. Monanan, a former assistant in our laboratory, who supervised most of 
details of the work. 
