508 Chronicles of Science. [July, 
Since the year 1851, when Schénbein communicated to the 
Medico-Chirurgical Society of London a memoir, in which he 
pointed out that the inhalation of ozonized air occasioned a painful 
affection of the chest,—a sort of asthma,—accompanied with a 
violent cough, the attention of the medico-meteorologist has been 
directed to the determination of the proportion of ozone in the atmo- 
sphere, and its relation, if any, to the prevalent diseases of the time or 
of the place.* Both in this country and in Germany careful registers 
have been kept of the variations in the amount of atmospheric ozone 
during a number of years. But we cannot as yet say that any very 
trustworthy results have been arrived at, as to the relations between 
its excess and deficiency, and the diseases which may have been most 
rife during the same period. This indefinite condition of the 
question may perhaps be in part explained by the somewhat inexact 
nature of the test employed. For, although the ozone papers may be 
sufficiently delicate to indicate absolute deficiency or excess of atmo- 
spheric ozone, yet the determination of minute shades of difference 
will vary much with the individual observer, with his power of 
appreciating the exact tint produced on his test paper, and of referring 
it to the corresponding shade on his reference paper. And it is, 
perhaps, to the difficulties which exist in comparing the results ob- 
tained by observers stationed in different localities, that we must, in 
some measure, ascribe the very different statements which have been 
made of its action on the animal frame. For whilst one set of ob- 
servers declares that there is a remarkable coincidence between an 
excess in the amount of atmospheric ozone and the prevalence of 
affections of the respiratory passages, on the other hand, M. de 
Piétra Santa t states that at Algiers, where bronchial affections are 
rare, ozone exists abundantly in the atmosphere. 
Again, the attempts which were at one time made to show that 
diseases fof the alimentary canal, and even cholera, were more rife 
when the proportion of ozone in the air was small, have not been 
borne out by subsequent investigators. 
More exact results of the power of ozone when in excess, to act 
upon the human frame may, however, be obtained by direct experi- 
ment, as when air is artificially ozonized, and animals are compelled 
to breathe it for a given period. This line of inquiry has now been 
followed out by various experimenters, Schénbein,$ Schwarzenbach, || 
* References to the following papers on the subject may prove useful to some 
of our readers :-— 
Spengler. Influenza und Ozon. Henle u. Pfs. Zeitschrift, vii 1. 1848. 
Heidenreich. Ozon und Katarrh, Neue med. chir, Ztg. vii. 3. 
Clemens. Wirkungen Ozonzerst : Gase auf den Mensch: Organismus. Henle. 
u. Pfs. Zeitschrift, vii. 2. 1848. 
Annales d’Hygiene publique. Paris. 1863. P. 439. 
+ This side of the question has been very recently advocated by Dr. Hjaltelin, 
of Reikjavik, in an able paper on “ Epidemic Pneumonia in Iceland,” in the year 
1863, published in the ‘Edinburgh Medical Journal,’ May, 1564. 
t ‘L’Union Médicale,’ 30 Mai, 1861. 
§ Henle und Pfs. Zeitschrift. N. F. Bd. 1. SS. 384, 
|| Canstatt’s Jahrb, 1851. 1, 128, 
