78 Transactions of the 



all others in whicli fevers and other contagious diseases 

 effect such awfal ravages. 



In August 1855, tests for ozone were applied in each of 

 the wards of the military hospital at Metz for twenty-four 

 hours, and were for several consecutive days without afford- 

 ing the slightest trace ; while, when suspended outside the 

 windows, it was immediately detected. Similar results have 

 been obtained under like circumstances. Dr. Berigny in the 

 Versailles hospitals found that test papers which, for fifteen 

 days inside the wards would give no trace, exposed outside, 

 and even in an empty ward, gave instantaneous indications. 

 At the same time ozone was remarkably deficient in Paris — 

 the tests exposed at the Conservatoire des Arts et Metiers 

 giving no trace. Thus it appears that the vitiated state of 

 the atmosphere is sufficient to account for the lack of ozone. 

 The amount of animal matter in air is tested by the 

 exposure of a solution of permanganate of soda, which is de- 

 colourized and decomposed by organic matter (the perman- 

 ganate being reduced first to manganic acid, and subse- 

 quently to the dioxide by the oxidation of the animal matter). 

 May we not from this infer that the hearLh-giving influences 

 of a country walk are due to the presence of ozone, since 

 ozone exists wherever there is active vegetation ? Fi-om these 

 considerations it has been concluded, that the presence of 

 cholera and other diseases of a sporadic nature, is due to the 

 absence or deficiency of ozone, while the presence of influenza 

 and other epidemic catarrhs is due to an excess of ozone. 

 Such a conclusion is somewhat hasty, and has lately met 

 with some severe criticism. ' Are these epidemics,' says 

 M. Naquet, 'owing to the disappearance of ozone, which 

 being no longer in sufficient quantity to destroy the mias- 

 mata, enable these to accumulate, or are they not owing to 

 the production of such a quantity of miasmata that the ozone 

 is not sufficient to destroy them ? ' In short, ' Are epidemics,' 

 says he, ' the cause or result of the disappearance of ozone ? ' 

 This is at present undetermined ; opinion inclines towards the 

 supposition that these epidemics are the cause and not the 

 result of the disappearance of ozone. Dr. Moffatt has made 

 some researches at great length upon the medico-meteorolo- 

 gical effects of ozone, and has demonstrated that the quantity 

 of ozone present in the atmosphere is greater when the baro- 

 metrical pressure is below the mean than when above ; that 

 it is more abundant on the sea coast than inland, on the 

 west than east of Great Britain, on elevated than on low 

 situations, in south-west than noi'th-east winds, on the wind- 



