60 



Dr. A. Bansome and Mr. A. G. B. Foulerton. 



ehromogenic bacteria, their function of pigment production. The patho- 

 genic action of a broth sub-culture of B. mallei, after the ozonisation, was 

 tested by intra-peritoneal inoculation of a male guinea-pig ; an ordinary 

 infection with characteristic lesions followed, the animal dying within 

 forty-eight hours. 



Experiment III. — "We now decided to subject the bacteria to a rather 

 more severe test than had been involved in the two preceding experi- 

 ments. The ozone was produced by passing oxygen under pressure 

 from a cylinder over a powerful " ozoniser," enclosed within a glass 

 cylinder, and then into the main feeding tube, as in the previous 

 experiment. The current used was an alternating one direct from the 

 street main. Small pieces of porcelain were, after inoculation with 

 the following bacteria, placed in the culture tubes : — 



1. Sarcina ventriculi. 



2. Micrococcus melitensis. 



3. Micrococcus candicans. 



4. Bacillus mallei. 



5. Bacillus diphtherial. 



6. Bacillus anthracis 



(from twenty-four hour old 

 culture in broth, non- 

 sporing). 



7. Bacillus anthracis 



(from old sporing culture on 

 potato). 



8. Bacillus typhosus. 



9. Bacillus coli communis. 



10. Bacillus pyocyaneus. 



1 1 . Bacillus pneumonice. 



1 2 . Bacillus prodigiosus. 



Duplicate tubes of each species were used for the experiment, the 

 first attempt to carry out which resulted in failure, owing to the 

 action of the ozone on the pieces of india-rubber tubing by which 

 the branches of the main feeding tube and the inlets into the culture 

 tubes were held in contact. Before the mixture of ozone and oxygen 

 had been passed into the series of culture tubes for ninety seconds, 

 every piece of india-rubber tubing was cut through, as if with a knife. 

 The joints were, therefore, made with pieces of bored cork, and the 

 experiment repeated. The mixture of ozone and oxygen was passed 

 through the tubes at the rate of 1*5 litre per minute for a period of 



N 



thirty minutes ; the yield of ozone, as estimated by titration with _ 



iodide solution, amounted to 0*072 gramme per minute. The percent- 

 age amount of ozone was therefore about 2*4 by volume. At the end 

 of thirty minutes the pieces of porcelain were dropped into tubes of 

 nutrient broth and incubated. On comparison with the various con- 

 trols it was obvious that the ozone had not affected the bacteria in such 

 a way as to impair either their capability for growth, or, in the case of 

 the ehromogenic organisms, their power of producing pigment. The broth 

 sub-culture of B. anthracis (non-sporing) after forty-eight hours' incuba- 

 tion at 37° C. was tested on a white mouse, and proved to be of normal 



