354 Toxic Action of Electric Discharge upon B. coli communis. 



No. 

 1 

 2 

 3 

 4 

 5 

 6 

 7 



per hour. 

 0-000197 grm. 

 0-000085 „ 

 0-000051 „ 

 0-000019 „ 

 0-000046 „ 

 0-000112 „ 

 0-000195 „ 



Total amount of H 2 2 

 No. per hour. 



8 0-000099 grm. 



9 0-000114 „ 



10 0-000029 „ 



11 0-000174 „ 



12 0-000677 „ 



13 0-001459 „ 



The variation is probably due to the different amounts of oxygen present, 

 and although quantitative determinations of the relative proportions were not 

 made,, the amounts of oxygen present in Nos. 12 and 13 were certainly larger 

 than in the other cases. 



Herein, then, may lie the explanation of the discrepancy alluded to above, 

 the unsuspected presence of small quantities of oxygen serving to produce 

 hydrogen peroxide in amount sufficient to cause the death of the bacteria. 

 From the foregoing results we are led to conclude that in the destructive 

 action of the discharge upon bacteria, the current itself plays no part, but that 

 the gaseous products of such a discharge in air are the actively toxic agents, 

 Causing the death of the organisms, independently of the current. 



v . : Summary. , . . 



l«j Electric discharge in air is fatal to bacteria exposed to its action. 

 . 2. The effect is due to the products of the interaction of the constituents of 

 the air, namely nitric and nitrous acid and ozone. 



3. Discharge in air-free hydrogen has no deleterious effect on the organisms, 

 but the presence of small quantities of air allows the formation of a toxic 

 substance, probably hydrogen peroxide, which again exerts a bactericidal 

 Action, tttiu .., . vj ; ; .j ! M • •■ ■ .• [ v • ^ 



4. It, . therefore, follows that electric discharges in which the current 

 density does, not exceed 10 -5 ampere per square centimetre do not exert any 

 directly i toxic action upon micro-organisms, a result which is contrary to 

 the statements made by some previous investigators.; :■:,;! 



