46 GENERAL PHYSIOLOGY OF BACTERIA 



culture fluid at the negative pole, and all the most resistant forms of 

 bacteria were destroyed at the positive pole, including anthrax and 

 subtilis spores. At the negative pole anthrax spores were killed also, 

 but subtilis spores remained alive for four hours. 



" 5. The continuous current alone, by means of DuBois-Reymond's 

 method of non-polarizing electrodes and exclusion of chemical effects 

 by ions in Kruger's sense, is neither bactericidal nor antiseptic. The 

 apparent antiseptic effect on suspensions of bacteria is due to electric 

 osmose. The continuous electric current has no bactericidal nor 

 antiseptic properties, but can destroy bacteria only by its physical 

 effects heat or chemical effects, the production of bactericidal 

 substances by electrolysis. 



" 6. A magnetic field, either within a helix of wire or between the 

 poles of a powerful electro-magnet, has no antiseptic or bactericidal 

 effects whatever. 



"7. Alternating currents of a three-inch Ruhmkorff coil passed 

 through bouillon cultures for ten hours favor growth and pigment 

 production. 



"8. High frequency, high potential currents Tesla currents have 

 neither antiseptic nor bactericidal properties when passed around a 

 bacterial suspension within a solenoid. When exposed to the brush 

 discharges, ozone is produced and kills the bacteria. 



"9. Bouillon and hydrocele-fluid cultures in test-tubes of non- 

 resistant forms of bacteria could not be killed by Rontgen rays after 

 forty-eight hours' exposure at a distance of 20 mm. from the tube. 



" 10. Suspensions of bacteria in agar plates and exposed for four 

 hours to the rays, according to Rieder's plan, were not killed. 



"11. Tubercular sputum exposeu to the Rontgen rays for six hours 

 at a distance of 20 mm. from the tube, caused acute miliary tubercu- 

 losis of all the guinea-pigs inoculated with it. 



" 12. Rontgen rays have no direct bactericidal properties. The 

 clinical results must be explained by other factors, possibly the pro- 

 duction of ozone, hypochlorous acid, extensive necrosis of the deeper 

 layers of the skin, and phagocytosis." 



J. GRAVITY, OSMOTIC PRESSURE, AGITATION, CHEMOTAXIS. 



1. Gravity. The majority of bacteria suspended in liquids are 

 not killed even by four hours' exposure to direct pressure of from 2000 

 to 3000 atmospheres (one atmosphere of pressure is equal to approxi- 



