40 
POPULAR SCIENCE REVIEW. 
in rendering it better fitted for the support of healthy life ; but 
Ozone at once restored to it active power. In this negative 
oxygen animals die as if under the influence of a narcotic ; in 
it the destruction of the products of organic decomposition is 
greatly impeded, and the presence of such products speedily 
renders it intolerably offensive ; dead animal tissue in it rapidly 
putrifies, and wounds in the bodies of living animals become 
sanious, dark, and unwholesome. 
Lastly, we gather from what has gone before a few facts 
bearing on hygienic measures, general and special. We may 
learn that as Ozone is used up in crowded localities, and as its 
presence is essential for the removal of the products arising 
from decomposing organic remains, no mere attention to 
ventilation, however important that may be, can suffice to 
make the air efficient for supporting healthy life unless the 
air be rendered active by the presence of Ozone. Hence it is 
an absurdity of the worst description to build hospitals for the 
sick in the midst of the crowded localities of the poor, and to 
ventilate them with air that has swept its way over a sea of 
ammoniacal compounds derived from the living and the dead. 
Hence, human dwellings built on the borders of lakes or 
pools charged with organic debris , or built near manure heaps, 
or over sewers, or on ground saturated with putrefying sub- 
stances, become necessarily the centres of the fever type of 
disease; not by necessity, as is vulgarly supposed, because 
the inhabitants are conscious of “ smell,” but because the air 
they 'breathe is reduced in active power, and poisons are being 
generated around them to which they are constantly exposed, 
and before which they fall a ready prey. 
The lecture is over : I have dealt with a subject that is in 
some sense a paradox, abstruse yet simple, unpractical and 
yet of all subjects the most practical when it is well known. 
In time there will be no paradox, but the hard and most 
mysterious labours of the scientific investigator will resolve 
themselves into a few easy propositions which all will under- 
stand. Then we shall take care to conserve Ozone where it 
should be conserved, to supply it like light in places where it 
cannot be always secured naturally ; and to neutralize it if, like 
the Roman centurion's soldiers, it comes when we do not want it. 
In Ozone another generation may actually see an article of 
commerce, and even now an “ Ozone Company ” might prove 
itself not merely a useful, but, as a sequence, a paying concern. 
Such a company could bleach, deodorize, disinfect, preserve 
meat and vegetables, and give sea air to every household 
that required it ; its “ supply ” could be as manageable as gas, 
and as cheap as water ; and with due precaution the lieges 
might make use of the agent as safely in their households as I 
and other men of science make use of it in the laboratory. 
