INFLUENCE OF PHYSICAL AGENTS. 163 
estimating the power of this agent to destroy the vitality of bacteria. 
The current was passed through a spiral wire which was wrapped 
around a test tube of glass, containing the microdrganism to be tested, 
suspended in distilled water. In a first experiment Bacillus prodigi- 
osus, suspended in sterilized distilled water and contained in test 
tubes having a capacity of two hundred and fifty cubic centimetres, 
was subjected to a current having an energy of 2.5 ampéres X 1.25 
volts for twenty-four hours. The temperature did not go above 
30° C. No development occurred when the microdrganism tested 
was subsequently planted in nutrient gelatin. Further experiments 
gave a similar result. It was found that stronger currents were 
effective in shorter time; but in no case was sterilization effected in 
less than an hour. 
Pressure.—D’ Arsonval and Charrin (1894) submitted a culture 
of Bacillus pyocyaneus to a pressure of fifty atmospheres, under car- 
bon dioxide. At the end of four hours cultures could still be ob- 
tained, but the bacillus had lost its power of pigment production. A 
few colonies were developed after six hours’ exposure to this pressure; 
but after twenty-four hours no development occurred. 
Agitation.—Meltzer (1894) has shown that the vitality of bacteria 
is destroyed by protracted and violent shaking, which causes a molec- 
ular disintegration of the cells. 
