1884] The Exhalation of Ozone by Flowering Plants. 477 
deleterious substances due to human respiration, insufficient ven- 
tilation, the presence of sewer gases, and many other causes. 
That the hygienic conditions of the air of living rooms is almost 
universally abominable is admitted by the best authorities, and it 
is also true that this bad air of our dwellings serves admirably as 
a culture fluid for the various disease-producing germs, How to 
obviate the ill effects arising from this unfortunate condition of 
things is a question of paramount importance. Since plants are 
capable of generating ozone, which has the power of destroying 
not only the organic impurities but even disease germs, it fol- 
lows that the requisite amount of flowering plants grown in our 
living rooms would, in a great measure, rid the air of these dele- 
terious substances, From these observations it will readily be 
conceded that the value of house-plants as hygienic agents can 
scarcely be overrated. That no possible objection can be urged 
against the practice of keeping blooming plants in our living 
rooms (excepting in the case of those having pronounced odors, 
as the tuberose, etc.) has been shown conclusively elsewhere, and 
the old time prejudice, we are happy to be able to state, is rap- 
idly dying out. 
Shall we discard the foliage varieties because they are incapa- 
ble of producing ozone? By no means; there are also important 
advantages to be derived from their presence. Not to speak of 
their esthetic influence, there is, as already pointed out, confided 
to the leaf the important function of transpiration or exhalation 
= Watery vapor. This process is carried on so actively by leafy 
Plants as to give them the power to raise the degree of humidity 
ofa closed apartment which is usually far below the health stand- 
ard, as the writer has shown in previous articles.’ It simply 
Sats to be said that, in view of these experiments, the 
rier! treasures of the green-house as well as foliage plants 
web be Welcomed into every household as being among our 
est sanitary agents. 
le eas : 
ae of piration of Plants,” Amer, NAT. for March, 1879; also “ Beneficent In- 
peutic Te Plants,” AMER. Nav. for Dec., 1879; also “ Hygienic and Thera- 
of House Plants,” Phila. Med. Times for May 8, 1880. 
