Before examining either of these apparently conflicting views, it is necessary to settle the meaning of certain often-repeated phrases, and to take a general survey of some physiological and chemical facts which are necessary to the proper understanding of the subject. There are two words universally employed, and often in a very loose and inexact manner, by all who kave paid any attention to the class of diseases in question. These words are contagion and infection. In many instances we read page after page of learned disputations, which would "Yes, Kate," said Landon, smiling with hap-never have been written had their author clearpiness, "from the very cradle, and I'll never leave you any more."

He kept his promisc. St. George Landon, Esquire, and Mistress Catherine Digby Landon, lived at the "Neck" for the remainder of their days, as did Alfred and his wife at the "Bayshore" estate near by. The gentleman from whom this history is derived enjoyed the per-ployed to indicate not only the tainted and morsonal acquaintance of the son of St. George Landon by this marriage.

CAUSES AND PREVENTION OF EPI-tagion to denote the reproduction of disease

any sort that have become active morbid agents by undergoing a change, either by fermentation or otherwise.

There are many circumstances which, though alone wholly insufficient to produce pestilence, yet, when acting together, may generate it, and must, if it should arise from other causes, greatly increase its intensity. Every one knows that epidemic diseases are most fatal in low, filthy, ill-ventilated, and crowded houses. There are numerous reasons for this. One of the most palpable is the direct vitiation of air by respiration.

When a mouse is put under a bell-glass he is at first as vivacious as he was in the open air. He frisks about, nibbles his cheese, and seems quite contented with his new abode. Presently he becomes anxious and restless, endeavors to escape, exhibits much uneasiness, and finally grows listless, languid, lethargic, and expires. Few readers have not shuddered at the record of the awful night spent by the English prisoners of Suraja ud Dowlah in the Black Hole of Calcutta-how they raved and struggled for a snuff of fresh air, and how, when morning broke, its rays shone upon twentythree ghastly survivors of the unhappy band of one hundred and forty-six who had been shut up the previous evening. But even these had not yet escaped the horrors of that night.

Nor does the evil stop here. The lungs throw off water as well as carbonic acid gas, and in that water is contained an animal substance which rapidly decomposes. This every one knows who enters a room in which persons have been sleeping all night. The air is close and stifling, and the nose becomes sensible of a peculiarly offensive odor-the smell of commencing putrefaction. This exhaled substance is of a viscous nature, and clings to the wall, the wood-work, the bed-clothes-a fact which travelers often discover on retiring to their rooms in crowded hotels. Now, if it is remembered that the lungs absorb from the air as well as exhale to it, we perceive how easy it is for this putrefying poison to be introduced to the blood through the delicate membranes of these organs. Our readers must be content to take our word for the fact that these effluvia are energetic in the production of disease, as we have no space for the proofs that could be accumulated to establish it.

It is evident that the depressing effects of foul air are not confined to those cases in which the immediate results of its poison are seen. Because it requires a given quantity of carbonic acid in the air to exhibit decided effects, it does not follow that a much lower proportion does not seriously impair the vital energies, and esSev-pecially the power of resisting disease. We eral of them died of typhus fever, the effect of are firmly convinced that many a case of scarthe poison they had then inhaled.

We have not far to seek for the cause of these unhappy effects. The blood, as it trav- | erses the system, carrying nutriment to every part, takes up from all the changing, wasting tissues the products of their decay. Carbonic acid is one of the chief of these products-a deleterious gas which, if allowed to remain in the blood, must speedily extinguish the flame of life. To prevent this fatal result, an escape for this deadly fluid has been provided in the lungs. In the minute cells of their delicate tissue an interchange of gases is effected. Carbonic acid escapes, and oxygen from the atmosphere takes its place. Health is impossible if this great function be interfered with, in even a slight degree. Every man uses daily, in respiration, thirty-three hogsheads of pure air, and gives off ten cubic feet of carbonic acid gas. He must have his supply of air, from seven to eight hundred cubic feet. But it will not answer to tie him to this. If you give him this supply in a close room, he will still be embarrassed; because, after he has contaminated it with his breath, the carbonic acid which he has exhaled begins to act like a poison upon him long before he has exhausted his stock of oxygen. It paralyzes his respiratory function, preventing the free escape of the gas contained in his blood. He then grows heavy. If he has slept, he is not refreshed; if he has been awake, he becomes languid, has headaches; he loses his energy, and does not recover it till after he has exposed himself for a sufficient length of time in the open air.

let fever or of measles proves fatal on account of an unperceived depression of the little sufferer's strength by previous continued exposure to an atmosphere tainted with carbonic acid and other exhalations from his own lungs. We know that all diseases of low grade, such as typhoid and typhus fever, prevail to a very great extent in ill-ventilated houses; we know that an epidemic inflammation of the eyes has been frightfully prevalent in the Irish workhouses, and that it has been traced to imperfect ventilation-the eye disease being merely the index of the general depression of the vital powers; we know, too, that in one of the transatlantic hospitals, the mortality went down from forty in a thousand to nine upon the adoption of a proper system of ventilation, and that it rose again to twenty-four on the subsequent abandonment of that system. These are only illustrations; hosts of similar facts could be cited from the records of medical science.

Now, what bearing has imperfect ventilation upon the progress of epidemics? As far as cholera is concerned, we have most significant answers to that question in the British reports. We cite but one instance as an illustration. At Tooting, the cholera broke out violently among the children in the work-house, while the prison entirely escaped. Upon inquiry it was ascertained that the inmates of the jail enjoyed the luxury of pure air at the rate of eight or nine hundred cubic feet for each individual, while the unhappy little paupers were limited to from one hundred and thirty-three to one hundred and fifty cubic feet each. The school-rooms

are particularly accused, as they were low and very badly ventilated. It was remarked that the boys enjoyed a comparative immunity from the attacks of the pestilence. This was attributed to the fact that the turbulent little fellows could not be restrained from breaking the windows of their room, while the more docile girls, not availing themselves of that rude method of obtaining a little fresh air, wilted in the foul atmosphere of their confined dens.

In

house, fever of a low, malignant type prevailed
among the unfortunate inmates of the latter.
In 1848, when cholera was sweeping over En-
gland, the wind blew from that quarter.
one morning, sixty children were taken ill with
the Asiatic plague. The authorities, aroused
to a sense of the peril of these poor people, in-
dicted the establishment as a nuisance, and
compelled the proprietor to close. Very speed-
ily the epidemic ceased. Five months after-

the wind blew from the direction of the factory. The stench which pervaded the work-house was overpowering. Forty-five boys, whose dormitories faced the factory, died of cholera; while the girls, whose windows looked in another direction, escaped.

This striking case might be fortified by numerous instances in which malignant disease has broken out on ship-board immediately after pumping out putrid bilge-water. The history of the epidemic of cholera in the Baltimore almshouse, is also very instructive on this point. The city of Baltimore was that year blessed with a very energetic Board of Health, which enforced, in spite of all opposition, the thorough cleansing of the city. Not a single case of the disease occurred within the city limits; while in the alms-house, just outside of the boundaries of the corporation, over a hundred of the inmates died. The investigation of the physician revealed the presence of an exceedingly offensive cess-pool on that side of the house which was most severely affected.

It is not only in close apartments that a viti-ward the filthy business was resumed; again ation of the air to an extent capable of producing disease is possible. The whole atmosphere of a neighborhood may be tainted so as to lay prostrate an entire population. Every one knows that powerfully-offensive odors are capable of inducing weakness amounting to actual fainting, in persons of a highly sensitive, nervous temperament. The exhaustion so speedily manifested in these cases exists, though not to a perceptible degree, in far sturdier frames. The reports of the Registrar-General of England disclose to us some very startling facts in reference to this matter. If any one were to select from among all the different occupations the healthiest men of a nation, he would probably choose the farmers and the butchers. Both are usually stout in frame and ruddy in complexion. Both are actively employed, have plenty of exercise and abundance of food. In one point, however, their circumstances widely differ. The farmer breathes the pure air of the country; the butcher inhales the atmosphere of the shambles and the slaughter-house, tainted with putrefying animal effluvia. The result is an instructive lesson as to the value of pure air. The rate of deaths per thousand among farmers between the ages of forty-five and fifty-five was 11.99 per thousand. The butchers of the same age died at 23-1 per thousand, so that their mortality is above double that of farmers. These two classes, indeed, occupy nearly the extremes of the table of mortality. The farmer is the healthiest man on the list, while there is but one who is worse off than the butcher, the innkeeper. Any one who knows how large a proportion of taverns are mere grog-shops, reeking with impurities and environed in filth, will not be surprised that the mortality among this class ascends to 28.34 in the thousand. To make the matter still more striking, let us compare the "bull-fronted, ruddy" butcher with the sallow shoemaker, whose figure on this list stands 15.3 in the thousand. The superior comfort of the butcher's circumstances increases our surprise at this unexpected discovery.

Let us now inquire how the history of pestilence bears upon this question. A single case is sufficient for our purpose. In Spitalfields there is a manufactory of artificial manure, where the exhalations of drying blood and night-soil taint the atmosphere, and fill it with disgusting odors. Immediately opposite this establishment is the work-house of the parish. It had been long observed that when the wind set steadily from the factory toward the work

Every

Dampness is another cause which predisposes to an attack of an epidemic disease. This need not surprise us, for we know that the skin is a great draining apparatus to sweep impurities out of the system. In every full-grown man, so closely are its minute tubes packed away that their entire length amounts to twenty-seven miles. If this extensive sewerage is dammed up, it is easy to see that a poison received by the lungs can not be so readily eliminated through the outer surface of the body. one is aware, by his own sensations, how a damp, close atmosphere oppresses him, and how evidently the action of the skin is interfered with. These considerations alone would lead us to anticipate a greater prevalence of epidemic diseases in damp than in dry districts. This is eminently true of Asiatic cholera, which follows the banks of rivers, and loves to dwell in damp, low situations. New Orleans and St. Petersburg -two cities which suffered terribly from this Oriental plague—are proverbial for their low, marshy site and the great humidity of their atmosphere.

It must not be supposed that the air is dry because there is little or no rain, or because the dampness is not directly perceptible to the senses. In long droughts, modern meteorology has taught us that the air is often heavily charged with moisture, which is made manifest by the proper instruments. When this damp atmosphere is also a hot one, disease, in some

ton very truly says, "is town air," and all the impurities in the latter are speedily absorbed by the former, so that water which stands exposed for any time to the atmosphere of a city during an epidemic is at least to be suspected. Much more may we anticipate disease from the use of water which is tainted by infiltration from a soil charged with organic impurities. Many facts have been cited in proof of the danger of using such water.

form, is almost inevitable. The reports of the Sanitary Commission of New Orleans on the Yellow Fever of 1853, and of the Special Committee of the American Medical Association on the Influence of the Hygrometric State of the Atmosphere on Health, are full of information on this head. In the latter we learn that, during that remarkable prevalence of sun-stroke in the city of New York in the summer of 1853a prevalence so great as almost to deserve the name of an epidemic-the dew-point had reach- A very striking instance is recorded in one ed the remarkable height of 84°. In Buffalo, of the reports of the Registrar-General of Great during the summer of 1854, the cholera seemed Britain. In the city of Manchester was a well, steadily to increase with the humidity of the at- in the immediate vicinity of a sewer, so badly mosphere until the epidemic attained its height. walled that the contents of the drain leaked into It is probably to this that we are to attribute it. Of ninety houses in its neighborhood, thirty the remarkable fact, often noticed during chol- used its water and sixty did not. In the forera epidemics, that the lower floors of buildings mer, there occurred nineteen cases of diarrhoea, suffer more severely than the upper. The air twenty-six of cholera, and twenty-five deaths; is always damper nearer the ground. Thus ain the latter, eleven cases of diarrhoea, none of difference in altitude of sixty feet, in the same cholera, and no death. As far as could be asexposure, has been known to make a difference certained, the houses were, in other respects, of 10 degrees in the dew-point. similarly situated.

The epidemic of 1854, in London, was very decidedly influenced by the character of the water. Two companies, the Lambeth and the Southwark and Vauxhall, supplied nine districts on the south side of the Thames. The former pumped up their water from the Thames at Ditton, the latter at Battersea. The fluid from the

the influence of the tide, tainted with the offal of the city, and swarming with infusoria. The water pumped up at Ditton was comparatively

Our account of the atmospherical conditions of pestilence would be very incomplete without some notice of that mysterious agent, ozone. Van Maram was the first who gave any hint of the remarkable change induced in oxygen by the electric fluid. After passing five thousand sparks from a powerful battery through a tube of oxygen gas, he observed that the gas had ac-last-named place was very impure, brackish from quired the peculiar smell so often noticed during the action of an electrical machine. The announcement of this fact created little stir in the scientific world, and led to no new discov-pure. eries. The whole matter was forgotten, till, in 1849, Schönbein, a German chemist, while decomposing water by means of the galvanic battery, observed the same odor, and turned his attention to the examination of the product. At first he thought it to be a new compound of hydrogen and oxygen, but afterward adopted the opinion of the French chemists, that it was a peculiar modification of the latter.

A more

The results of the use of these two liquids were very striking. Out of a population of 166,906 persons drinking the water of the Lambeth Company, there died 611 from cholera; while out of 268,171 drinking the water supplied by the Southwark and Vauxhall Company, there perished, of the same disease, 3476. exact comparison was made in a district containing about 20,000 inhabitants, one-half of whom were supplied by one company and onehalf by the other. Those who drank the better water lost 57 by cholera, while those who drank the worse lost 164 by that pestilence. The facts are so strong that comment would only weaken their force.

It manifests all the properties of oxygen in a highly energetic degree. It greatly increases the rapidity of oxydation in all oxydizable bodies. Its action upon public health appears to be decided. When it is present in excess, diseases of the lungs, especially influenza, are prevalent. When it is deficient, on the contrary, fevers and all those diseases which are believed to depend upon a species of fermentation induced in the blood are common. The ordinary interpretation of this fact is, that these disorders depend upon the presence in the atmosphere of various organic matters which are undergoing a molecular change in their progress toward complete disorganization, and that ozone hastens their oxydation, burns them up, as it were, and so renders them innocuous. Epidemics of cholera | seemed exposed to equal peril. are said to be characterized by a total absence of this purifying agent.

The drinking water used by large communities is another matter to which great attention should be paid. "Town water," as Dr. Bar

Other depressing causes which favor the spread of pestilence might be noticed. Indeed, it may be said, in general terms, that any course of life which tends to lower the vital powers must predispose to epidemic disease. Hence, we find that there seem always to be certain predestined thousands who must succumb to an epidemic; and when they are slaughtered, the malignant power, as if appeased by the sacrifice, passes on, and leaves untouched many who

After making all these allowances, however, there still remains the question, What is the exciting cause of a given form of epidemic discase-cholera, for example? For ages, cities have been filthy, men have drunk foul water,

termined to establish a cordon sanitaire against the inroads of this dreaded pestilence, which was ravaging their neighborhood. They accordingly stationed guards along the few lines of communication leading into their village. "When engaged, however, in keeping up our cordon with apparent success," says our author, "cholera entered the place in a way which it was impossible we could have calculated. A Cromarty

ozone has been at times deficient; dampness communicability. The people of Cromarty dehas been abundant, the air has been stagnant, and all these conditions have frequently coincided. Why, then, should cholera have been unknown to the civilized world till these last years? What is the specific cause which has given rise to this peculiar form of disease? Why should it have remained for so many ages pent up in the hot, damp jungles of its native India, and only issued to devastate the world during the nineteenth century? Granting the possibil-fisherman had died of the disease at Wick rathity of its local origin, it seems impossible to account for the facts of its progress by the doctrine of exclusive local origin. The chances against the successive recurrence of local causes along the lines of human intercourse, in a regular geographical progress, become so overpowering that the mind refuses to believe in the possibility of such a systematic course of accidents. There remains but one hypothesis, which, in the present state of our knowledge, seems at all tenable, that which attributes the spread of the disease to the movements of men. Those who hold this opinion maintain that cholera is communicable. This term is adopted to avoid the words contagion and infection, to which meanings are attached that render them imperfect exponents of the sense in which the transmissibility of this disease from man to man is understood.

There are many facts which appear inexplicable on any other theory. Our readers have only to recall the history of the journeys from India over the continent of Asia-the route by which it entered Europe-and its subsequent passage to America, to be convinced that it followed the lines of greatest travel. How it could have done this in two universal epidemics, occurring at an interval of nearly twenty years from one another, without being in some manner dependent upon human intercourse, it is difficult to imagine.

er more than a month previous, and all the
clothes which had been in contact with the body
were burned by the Wick authorities in the open
air. He had, however, a brother on the spot,
who had stealthily appropriated some of the bet-
ter pieces of dress; and these he brought home
with him in a chest; though such was the dread
with which he regarded them that for more
than four weeks he suffered the chest to lie be-
side him unopened. At length, in an evil hour,
the pieces of dress were taken out, and, like the
'goodly Babylonish garment,' which wrought
the destruction of Achan and the discomfiture
of the camp, they led, in the first instance, to
the death of the poor, imprudent fisherman, and
to that of not a few of his townsfolk immedi-
ately after. He himself was seized by cholera
on the following day; in less than two days more
he was dead and buried; and the disease went
creeping about the streets and lanes for weeks
after-here striking down a strong man in the
full vigor of middle life-there shortening, ap-
parently by but a few months, the span of some
worn-out creature, already on the verge of the
grave."

Many other cases, similar to this, might be cited, but we forbear to multiply individual facts. The whole history of the pestilence shows that cholera is undoubtedly communicable. Those who deny this, level their arguments against the hypothesis of contagion, and cite numerous instances to prove that the disease is not directly transmissible. In doing this, however, they are attacking a man of straw which themselves have set up. It is not claimed that the disease is communicated, like small-pox, by an immediate emanation from the body of the cholera patient. It is simply asserted that the pestilence is propagated in some way from man to man, the method of the propagation being left for future observation.

This notion, which we derive from a general survey of the history of Asiatic cholera, is strengthened by numerous individual facts. We refer our readers to the paper on this epidemic, for the very striking cases of Sarepta, the Moravian colony in Russia, and of the English and French colonies of Mauritius and Isle de Bourbon. It is remarkable that the history of the recent epidemic in the Mauritius, in 1854-5, is almost an exact repetition of that of 1819. Again, the disease broke out in Port Louis Concerning that method, there are a variety shortly after the arrival of a ship from India, of opinions. Dr. Snow, of London, thinks that and spread thence over the island. Again, the it takes place through the drinking water. This, Isle de Bourbon established a long and strict he conceives, becomes tainted with the discharges Quarantine for all vessels arriving from the Mau- from cholera patients, and so propagates the disritius, and this time it entirely escaped a visit- ease. This view, while supported by numeration of the epidemic, although prior to the out-ous facts, is too exclusive to account for all the break of the pestilence in the neighboring island, phenomena. Others believe the atmosphere to there had been a few cases of cholera in Bour-be the medium of communication. Numerous bon.

The introduction of the disease into the little village of Cromarty is very circumstantially narrated by Hugh Miller, the Scottish geologist, and throws much light on the question of

examinations, chemical and microscopic, have been made, but have failed to reveal any thing peculiar, save the absence of ozone. Spores of fungi and microscopic animalcules called vibriones were discovered in the air of a cholera ward,