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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.