It is pretty well known that researches by Matteucci, Du Bois-Reymond,
and others, have made us acquainted with the influence of electricity
and galvanism on the muscular system of animals, and that important
physiological effects have been attributed to this influence, more
than perhaps we are warranted in assuming in the present state of our
knowledge. That an influence is exerted in some way, is clear from the
difference in our feelings in dry and wet weather: it has been
supposed, however, that the effects on the nervous system are not
produced by an accumulation of positive or of negative electricity,
but by the combination of the two producing dynamic electricity. While
these points are undergoing discussion, we have an opportunity of
bringing before our readers the results of investigations bearing on
the general question.
Most persons are aware of the fact, that a peculiar taste follows the
application of two different metals to the tongue in a popular
galvanic experiment. This taste is caused by the azotic acid formed
from the oxygen and azote of the atmosphere. An electric discharge,
too, is accompanied by a smell, which smell is due to the presence of
what is called ozone; and not long ago M. Schoenbein, of Basel, the
inventor of guncotton, discovered ozone as a principle in the oxygen
of the atmosphere; and it is considered to be the _active_ principle
of that universal constituent. Later researches have brought out a
striking analogy between the properties of ozone and chlorine, and
have led to conclusions as to the dangerous effect which the former
may produce, in certain cases, on the organs of respiration. Some idea
of its energy may be formed from the fact, that mice perish speedily
in air which contains one six-thousandth of ozone. It is always
present in the atmosphere in a greater or lesser degree, in direct
relation with the amount of atmospheric electricity, and appears to
obey the same laws in its variations, finding its maximum in winter
and its minimum in summer.
Ozone, in scientific language, is described as 'a compound of oxygen
analogous to the peroxide of hydrogen, or, that it is oxygen in an
allotropic state--that is, with the capability of immediate and ready
action impressed upon it.' Besides being produced by electrical
discharges in the atmosphere, it can be obtained artificially by the
passing of what is called the electrical brush into the air from a
moist wooden point, or by electrolyzed water or phosphorus. The
process, when the latter substance is employed, is to put a small
piece, clean scraped, about half an inch long, into a large bottle
which contains just so much of water as to half cover the phosphorus,
and then closing the mouth slightly, to guard against combustion, to
leave it standing for a time in a temperature of about 60 degrees.
Ozone soon begins to be formed, as shewn by the rising of a light
column of smoke from the phosphorus, which, at the same time, becomes
luminous. In five or six hours, the quantity will be abundant, when
the bottle is to be emptied of its contents, washed out, and closed
for use and experiment.
Whichever way the ozone be produced, it is always identical in its
properties; and these are described as numerous and remarkable. Its
odour is peculiar, resembling that of chlorine, and, when diluted,
cannot be distinguished from what is called the electric smell. When
largely diffused in atmospheric air, it causes unpleasant sensations,
makes respiration difficult, and, by acting powerfully on the mucous
membranes, produces catarrhal effects; and as such air will kill small
animals, it shews that pure ozone must be highly injurious to the
animal economy. It is insoluble in water, is powerfully electromotive,
and is most strikingly energetic in numerous chemical agencies, its
action on nearly all metallic bodies being to carry them at once to
the state of peroxide, or to their highest point of oxidation; it
changes sulphurets into sulphates, instantaneously destroys several
gaseous compounds, and bleaches indigo, thus shewing its analogy with
chlorine.
In proceeding to the account of his experiments, M. Schoenbein shews,
that gases can be produced by chemical means, which exercise an
oxidizing influence of a powerful nature, especially in their
physiological effects, even when diffused through the atmosphere in
very minute quantities: also, that owing to the immense number of
organic beings on the earth, their daily death and decomposition, an
enormous amount of gases is produced similar to those which can be
obtained by artificial means; and besides these, a quantity of gaseous
or volatile products, 'whose chemical nature,' as the author observes,
'is as yet unknown, but of which we can easily admit that some, at
least, diffused through the air, even in very small quantities, and
breathed with it, exert a most deplorable action on the animal
organism. Hence it follows, that the decomposition of organic matters
ought to be considered as one of the principal causes of the
corruption of the air by miasmatic substances. Now, a continuous
cause, and acting on so vast a scale, would necessarily diffuse
through the atmosphere a considerable mass of miasmatic gases, and
accumulate them till at length it would be completely poisoned, and
rendered incapable of supporting animal life, if nature had not found
the means of destroying these noxious matters in proportion as they
are produced.'
The question then arises: What are the means employed for this
object? M. Schoenbein believes that he has found it in the action of
ozone, which is continually formed by the electricity of the
atmosphere, and is known to be a most powerful agent of oxidation,
causing serious modifications of organic bodies, and, consequently, of
their physiological action. 'To assure myself,' he pursues, 'that
ozone destroys the miasma arising from the decomposition of animal
matters, I introduced into a balloon containing about 130 pints of
air, a piece of flesh weighing four ounces, taken from a human corpse,
and in a very advanced state of putrefaction. I withdrew it after a
minute; the air in the balloon had acquired a strong and very
repulsive odour, shewing that it was charged with an appreciable
quantity--at least for the smell--of miasm caused by the putrefaction.
'To produce ozone, I introduced into the infected balloon a stick of
phosphorus an inch long, with water sufficient to half cover it. At
the same time, for the sake of comparison, I placed a similar quantity
of phosphorus and water in another balloon full of pure atmospheric
air. After some minutes, the reaction of ozone in the latter was most
evidently manifested, while no trace of it was yet apparent in the
former, which still gave off an odour of putrefaction. This, however,
disappeared completely at the end of ten or twelve minutes, and
immediately the reaction of the ozone was detected.'
The conclusion drawn from this experiment is, that the ozone destroyed
the miasm by oxidation, and could only make its presence evident after
the complete destruction of the noxious volatile substances. This
effect is more strikingly shewn by another experiment.
A balloon of similar capacity to the one above mentioned was charged
as strongly as possible with ozone, and afterwards washed with water.
The same piece of flesh was suspended within it; and the opening being
carefully closed, it was left inside for nine hours before the air of
the balloon presented the least odour of putrefaction. The air was
tested every thirty minutes by an ozonometer, and the proportion of
ozone found to be gradually diminishing; but as long as the paper of
the instrument exhibited the slightest trace of blue, there was no
smell, which only came on as the last signs of ozone disappeared.
Thus, all the miasm given off by the piece of flesh during nine hours
was completely neutralised by the ozone with which the balloon had
been impregnated, so small in quantity as to be but the 6000th part of
a gramme. One balloon filled with ozonified air, would suffice to
disinfect 540 balloons filled with miasmatic air. 'These
considerations,' says M. Schoenbein, 'shew us how little the miasma of
the air are to be appreciated by weight, even when they exist therein
in a quantity very sensible to the smell, and how small is the
proportion of ozone necessary to destroy the miasm produced by the
putrefaction of organic substances, and diffused through the
atmosphere.'
The presence of ozone in any vessel or in the atmosphere, may be
detected by a test-paper which has been moistened with a solution
composed of 1 part of pure iodide of potassium, 10 parts of starch,
and 100 parts of water, boiled together for a few moments. Paper so
prepared turns immediately blue when exposed to the action of ozone,
the tint being lighter or darker according to the quantity.
Schoenbein's ozonometer consists of 750 slips of dry bibulous paper
prepared in the manner described; and with a scale of tints and
instructions, sufficient to make observations on the ozone of the
atmosphere twice a day for a year. After exposure to the ozone, they
require to be moistened to bring out the colour.
M. Schoenbein continues: 'We must admit that the electric discharges
which take place incessantly in different parts of the atmosphere, and
causing therein a formation of ozone, purify the air by this means of
organic, or, more generally, oxidizable miasma; and that they have
thus the important office of maintaining it in a state of purity
suitable to animal life. By means of atmospheric electricity, and,
indirectly, nature thus attains on a great scale the object that we
sometimes seek to accomplish in a limited space by fumigations with
chlorine.
'Here, as in many other cases, we see nature effecting two different
objects at one stroke. For if the oxidizable miasma are destroyed by
atmospheric ozone, they, in turn, cause the latter to disappear, and
we have seen that it is itself a miasm. This is doubtless the reason
why ozone does not accumulate in the atmosphere in greater proportion
than the oxidizable miasma, notwithstanding the constant formation of
one and the other.
'In all times, the idea has been held, that storms purify the air, and
I do not think that this opinion is ill-founded. We know, in fact,
that storms give rise to a more abundant production of ozone. It is
possible, and even probable, that sometimes, in particular localities,
there may not be a just relation between the ozone and the oxidizable
miasma in the air, and that the latter cannot be completely destroyed.
Hence, in accordance with the chemical nature and physiological
influence of these miasma, they would exert a marked action on the
animal economy, and cause diseases among the greater number of those
who breathe the infected air. But numerous experiments prove that, as
a rule, the air contains free ozone, though in very variable
proportions; from which we may conclude that no oxidizable
miasm--sulphuretted hydrogen, for example--can exist in such an
atmosphere, any more than it could exist in air containing but a trace
of chlorine.
'I do not know if it be true, as has been advanced by Mr Hunt and
other persons, that ozone is deficient in the atmospheric air when
some wide-spread malady, such as cholera, is raging. In any case, it
would be easy, by means of the prepared paper, to determine the truth
or fallacy of this opinion.
'There is one fact which should particularly engage the attention of
physicians and physiologists, which is, that, of all seasons, the
winter is distinguished by the greatest proportion of ozone; whence it
follows, that during that season the air contains least of oxidizable
miasma. We can say, therefore, with respect to this class of miasma,
that the air is purer in winter than in summer.
'All my observations agree in shewing, that the proportion of ozone in
the air increases with the height; if this fact be general, as I am
disposed to believe, we must consider the upper regions of the
atmosphere as purer, with regard to oxidizable miasma, than the lower.
'The appearance of certain maladies--intermittent fever, for
example--appears to be connected with certain seasons and particular
geographical conditions. It would be worth while to ascertain, by
ozonometric observations, whether these physiological phenomena have
any relation whatever with the proportion of ozone contained in the
air in which they occur.
'Considering the obscurity which prevails as to the cause of the
greater part of diseases, and the great probability that many among
them owe their origin to the presence of chemical agents dispersed in
the atmosphere, it becomes the duty of medical men and physiologists,
who interest themselves in the progress of their science, to seize
earnestly all the means by which they may hope to arrive at more exact
notions upon the relations which exist between abnormal physiological
phenomena and external circumstances.'
Such is a summary of M. Schoenbein's views as communicated to the
Medical Society of Basel; and we the more readily accord them the
publicity of our columns, as, apart from the intrinsic value of the
subject, it is one which has for some time excited the interest of
scientific inquirers in this country. During the late visitation of
cholera, reports were frequently spread that the atmosphere was
deficient in ozone.