Conditions Prejudicial to Growth of Bacteria 43 



non-resistant forms of bacteria even if the temperature 

 is artificially kept below 37 C. The effect is due to the 

 formation of germicidal electrolytic products in the culture. 

 Anthrax spores are killed in two hours. Subtilis spores 

 were still alive after the current was passed for three hours. 



4. A continuous current passed through bouillon cultures 

 of bacteria produces a strongly acid reaction at the positive 

 pole, due to the liberation of chlorin which combines with 

 oxygen to form hypochlorous acid. The strongly alkaline 

 reaction of the bouillon culture at the negative pole is due 

 to the formation of sodium hydroxid and the liberation 

 of hydrogen in gas bubbles. With a current of 100 milliam- 

 peres for two hours it required 8.82 milligrams of H 2 SO 4 

 to neutralize i c.c. of the 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 sub- 

 tilis spores remained alive for four hours. 



5. The continuous current alone, by means of Du Bois- 

 Reymond's method of non-polarizing electrodes, and exclu- 

 sion of chemic effects by ions in Kruger's sense, is neither 

 bactericidal nor antiseptic. The apparent antiseptic effect 

 on suspension 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 chemic effects (the production of bactericidal 

 substances by electrolysis). 



6. A magnetic field, either within a helix of wire or be- 

 tween the poles of a powerful electro-magnet, has no anti- 

 septic 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 cur- 

 rents 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 dis- 

 tance of 20 mm. from the tube. 



10. Suspensions of bacteria in agar plates and exposed 



