OZONE. 355 



the country air, while air in the crowded parts of large cities 

 has no ozone at all, nor has the air of inhabited rooms. 



So far as we have gone, we might be disposed to speak 

 unhesitatingly in favour of the effects produced by ozone. 

 We see it purifying the air which would otherwise be loaded 

 by the products of decomposing matter, we find it present in 

 the sea air and the country air which we know to be so 

 bracing and health-restoring after a long residence in town, 

 and we find it absent just in those places which we look 

 upon as most unhealthy. 



Again, we find further evidence of the good effects of 

 ozone in the fact that cholera and other epidemics never 

 make their dreaded appearance in the land when the air is 

 well supplied with ozone or in what the meteorologists call 

 " the ozone-periods," And though we cannot yet explain 

 the circumstance quite satisfactorily, we yet seem justified 

 in ascribing to the purifying and disinfecting qualities of 

 ozone our freedom at those times from epidemics to which 

 cleanliness and good sanitary regulations are notedly 

 inimical. 



But there is a reverse side to the picture. And as we 

 described an experiment illustrating the disinfecting qualities 

 of ozone before describing the good effects of the element, 

 we shall describe an experiment illustrating certain less 

 pleasing qualities of ozone, before discussing the deleterious 

 influences which it seems capable of exerting. 



Dr. Richardson found that when the air of a room was 

 so loaded with ozone as to be only respirable with difficulty, 

 animals placed in the room were affected in a very singular 

 manner. " In the first place," he says, " all the symptoms 

 of nasal catarrh and of irritation of the mucous membranes 

 of the nose, the mouth, and the throat were rapidly induced. 

 Then followed free secretion of saliva and profuse action 

 of the skin perspiration. The breathing was greatly 

 quickened, and 'the action of the heart increased in pro- 

 portion," When the animals were suffered to remain yet 

 \onger within the room, congestion of the lungs followed, 



