EFFECTS OF OZONE ON THE AIR. 259 



" Each time that cholera has disappeared from 

 amongst us, it has been rapidly followed by 

 influenza. At the meeting of the British Asso- 

 ciation at Swansea, Dr. MofFatt communicated 

 the remarkable fact, that the prevalence of in- 

 fluenza and the spread of catarrhal affections were 

 invariably connected with an excess of ozone in 

 the atmosphere." 



From these considerations it may be gathered 

 that, upon this theory, the presence of cholera 

 is connected with the absence or deficiency of 

 ozone ; while the presence of influenza and epi- 

 demic catarrhs, is due to the excessive pre- 

 sence of ozone in the air. Also, that a certain 

 amount of ozone is necessary in order to sus- 

 tain -the entire salubrity of the atmosphere, 

 in consequence of its promoting the property 

 of destroying noxious occasional ingredients in 

 the air. It has been noticed that Birmingham 

 and Berlin have generally escaped the severity 

 of the infliction of cholera; and this has been 

 attributed to the metal manufactories of these 

 towns, which are abundant sources of ozone. 

 But in the recent epidemic, Birmingham was 

 visited with it, though only to a moderate ex- 

 tent. A great mystery still hangs, over the 

 cause and nature of this as well as of all pesti- 

 lences, but light may be expected to be thrown 

 on the subject as we advance in knowledge. 

 Known or unknown, we must not fail to ac- 



