1909] STONE—ELECTRICITY AND MICROORGANISMS 373 
in the preceding series. In all instances corresponding jars were 
employed in the normal and electrically treated yeast, and the condi- 
_ tions were identical so far as they could be made in every way in all 
cases. From o.5 to 5 or more of yeast were placed in each jar in 
the various experiments, and either a solution of molasses (about 5 
per cent.) or a standard nutrient solution was used. The nutrient 
solution was made up as follows: 
Grams 
Calcium nitrate? 35.) 2.4 a Se 6.0 
Potassium nitvate: 2 525 1:5 
Magnesium sulfate...............-.. $25 
Neutral potassium phosphate........ 1.5 
Sodium chiorid |. S2.A aa is 
Cane sugar. a ae ee 125.0 
Distilled water. 2202 3 2500.0 
This solution was not chosen on account of its being the best 
adapted for this purpose, but it proved to be satisfactory. 
The yeast used in these experiments was from the ordinary com- 
) mercial yeast cakes, which were cut into cubes and carefully weighed. 
__ The yeast was then put into mortars containing the nutrient solution 
_ and the cells carefully separated by repeated stirring. After the yeast 
_ Cells were well separated they were placed in their respective bottles. 
The mortar was thoroughly rinsed and care was taken to have the 
_ Same amount of yeast in each. The bottles containing the yeast were 
_ completely filled and connected by means of glass tubes to graduated 
: cylinders or burettes containing water, and as CO, was given off, the 
: displacing of water was noted at intervals and recorded. The follow- 
ing table gives the results of some experiments with yeast. 
: The experiments (see table XIII) had a duration of 1.5 hours to 
_ 4 days, and in all instances the amount of CO, given off was greater 
_ in the electrically treated than in the normal or those not stimulated. 
4 The experiments were conducted on different days and at different 
4 temperatures, most of them being at room temperatures, and as there 
_ Was no heat on in the laboratory at the season of the year in which 
| many of these experiments were conducted, the temperature was 
naturally somewhat variable. Ina, b,c, g, and h, however, the bottles 
Containing the yeast were in water baths and were kept under condi- 
tions nearer to the optimum for yeast (32—38° C.), hence the per- 
