Part 116

Cholera is endemic in no other country than India, and more particularly in Bengal. When it has occurred elsewhere it has invariably been carried from India. The cholera poison has been imagined to be of an aërial nature, but its diffusion has no relation whatever to the velocity or the direction of the wind. In no instance whatever has its rate of progress exceeded that of man on land or water, nor has it ever taken a direction different from that of commercial or military movements. On land it has usually crept from place to place, and if sometimes it has seemed to leap across wide spaces, and even seas and oceans, it has never invaded any inland town or seaport without having been brought thither from a point already affected with the disease. Nor, having once entered an inland or seaboard town, does it spread equally therein in all directions, but prevails chiefly in the quarter immediately surrounding the place of its entrance. If appropriate sanitary measures are enforced, it is sometimes confined to that quarter, and, in the case of quarantine stations, it has repeatedly been prevented from extending beyond them. This statement may be illustrated by the fact that of fourteen epidemics of cholera at Staten Island, the quarantine station of New York, all but four were prevented from reaching that city. When the disease does overleap the barrier opposed to it, its origin and subsequent course can usually be traced.

A high atmospheric temperature is everywhere associated with the prevalence of cholera. Its origin in the hot climate of Hindostan and its general progress prove this conclusively. In nearly all of the places where a great difference exists between the summer and the winter temperature the disease has disappeared during the cold season, and attained its greatest intensity during the hot months of the year. The only apparent exception to this rule is, that cholera has prevailed in several Russian, Swedish, and Norwegian cities during the winter. But these very exceptions confirm the rule; for in the countries mentioned the intense cold of the winter compels the inhabitants to seal their houses by every possible means, while the atmosphere within them is kept at a high temperature by huge stoves, which hinder ventilation, and indeed render it almost impossible. Difference of temperature likewise explains the fact that of two cholera-ships arriving from Havre, the one at New York and the other at New Orleans, in December, 1848, the former did not disseminate the disease, but the latter formed the starting-point of an epidemic which lasted all the winter.

A good deal has been written of the predisposing causes of cholera, and poverty, crowding, filth, intemperance, and depression of spirits have been given prominent places in the catalogue. But to any one familiar {721} with the history of epidemic diseases it will at once be apparent that every one of these conditions favors the spread of all communicable infectious diseases. There is not the slightest evidence that these agencies, singly or combined, can generate cholera or favor its spread apart from the presence of the specific poison of the disease and the facility with which it is transmitted from the sick to the well whenever the population is crowded, poor, of filthy habits, and weakened by dissipation. Because among such people intemperance prevails, this vice has been regarded as predisposing to cholera. Apart from the brutish mode of living of drunkards, there is nothing to show that they are more liable to cholera than the most abstemious of water-drinkers. On the contrary, it is notorious that during cholera epidemics drunkards in the better classes of society enjoy a certain degree of immunity from the disease; which it is easy to explain on the ground that they imbibe but little water, which is the main channel through which the infectious principle of the disease is spread.

The specific cause of cholera is taken into the alimentary canal, and acts through it to produce the characteristic symptoms of the disease. It is conveyed from the sick to the well by means of the gastro-intestinal discharges, either moist or dry; in the former state, by means of drinking-water, and in the latter through the air, whose suspended noxious particles are received into the fauces and swallowed. There is reason to believe that the poison does not enter the system through the lungs, or through any other channel than the gastro-intestinal canal. W. B. Carpenter appears to hold, however, that the poison may be absorbed through the lungs. To this view there are two objections: 1, That whatever is taken into the mouth or throat by inspiration may very well be swallowed; and, 2, that all the primary lesions of cholera affect the digestive and not the respiratory apparatus. It is not at all necessary to the propagation of cholera that its excreta should be furnished by persons laboring under the fully-formed disease. A specific choleraic diarrhoea is as infectious as the evacuations which occur in completely developed cholera. But neither will propagate the disease through the air to a distance. The tendency to its propagation in this manner depends chiefly upon the concentration of the poison; thus, it much more frequently occurs in close than in well-ventilated rooms or than in the open air. It has been argued that cholera is not contagious, because so few, comparatively, of the attendants upon cholera patients contract the disease. On the other hand, as some of them are attacked, this positive fact outweighs an indefinite number of negative instances. It should also be noted that different diseases enter the system and infect it through different channels--some through the lungs, others through the alimentary canal, etc. Small-pox, the most contagious of all diseases, is introduced through the air-passages, and is probably harmless when its virus is taken into the stomach. That the converse of this proposition applies to cholera is sustained by the whole history of the disease. Cholera poison may be taken to considerable distances in either a moist or a dry condition. In the former state it is mainly conveyed by water, as in rivers, water-pipes, etc.; in the latter, by fomites and especially by clothing saturated or merely soiled with cholera discharges, and which may retain their infectious quality for an indefinite time.

{722} Great stress has been laid upon the humidity and foulness of the soil, a damp atmosphere, filth, crowding, etc., as elements in the production of cholera, but in reality they have no more essential relation to it than to any other disease that occurs epidemically. Cholera may prevail whether they are present or absent. It is evident that from the earliest historical periods all of these causes of disease have existed, and in Europe much more generally and excessively than during the present century, and that they have never been removed in Asia Minor, Egypt, Arabia, and Africa. Yet cholera never was known in any of these countries until it was brought into them about the end of the first third of the present century.

According to Pettenkoffer, cholera is most prevalent when the subsoil water is lowest, and least so when the subsoil water is highest. It would be more descriptive of the fact to say that, so far as cholera has anything to do with the condition of the soil, it is most apt to be severe and prevalent when very dry weather follows a very wet period. Such circumstances are the most favorable to putrefactive fermentation and the dissemination of its products, which thus reach wells of drinking-water, and even rivers, especially when sewers empty into the latter. The identity of this explanation with that which is generally accepted for the dissemination of typhoid fever is too evident to be insisted upon. We might go farther, and say that, in typhoid fever as in cholera, the disease is communicated, although exceptionally, by the air of the sick room and by the exhalations of the soiled fomites of the patient. Now, if typhoid fever resembled cholera not only in being transmitted by means of the dejections, but also in its poison being derived from one primary source only, the analogy between the causes of the two diseases would be very striking indeed. But, in point of fact, the typhoid-fever poison may probably be generated de novo by fecal fermentation and other forms of putrefaction, and the disease is only exceptionally communicable; whereas, the poison of cholera, once received, is conveyed from man to man and far and wide through various channels; but, so far as is known, it has but one primary source, and that is in India. Lebert states that he did not find the localities that are the ordinary seats of typhoid fever peculiarly liable to invasions of cholera. But it must be noted that typhoid fever is very far from being exclusively a disease of the poor, squalid, and vicious. Like death itself, "regum turres pauperumque tabernas æquo pede pulsat;" while cholera much more commonly plants itself and disseminates its seeds in the rank soil of moral and physical degradation.

All morbid causes whatever, derived from race, climate, religion, dwellings, food, clothing, habits of living, etc., have no more to do with the development of cholera than with that of the eruptive fevers, and even less than with the causation of typhus and typhoid fevers and dysentery. The eruptive fevers are caused, as cholera probably is, by specific germs which no known combination of natural causes has ever developed, while the poisons of the other diseases named appear to be generated anew whenever certain more or less definite physicial conditions coexist. It would seem that cholera differs radically from all of these affections by the fact that its cause does not enter the circulation, but confines its direct operation to the gastro-intestinal mucous membrane. In this way it becomes intelligible that while, on the one hand, physicians and nurses of {723} cholera patients, although often, in fact, yet in relation to their numbers, are comparatively seldom infected, provided they duly observe proper sanitary rules, the disease, on the other hand, spreads like wildfire among those who drink water polluted by cholera excretions, and only a little less rapidly among people crowded into ill-ventilated apartments along with cholera patients.

The special fomites of the cholera poison are articles of clothing and furniture soiled with the discharges of the sick, and the emanations from privies, sewers, etc. into which these discharges have been cast. Many considerations render it probable that a very small quantity of cholera matter may suffice to render infectious a very large quantity of liquid, and especially of matters in process of putrefactive fermentation, and that the gaseous or vaporous emanations from them become diffused in the atmosphere and infect all who imbibe them. But water contaminated by cholera discharges is the most rapid and efficient agent in disseminating the disease. Innumerable instances of this mode of action are furnished by its history in Asia and Africa, where water is often scarce, and naturally so impure that its additional defilement by cholera dejections is apt to pass unnoticed. From the illustrations of this proposition which might be adduced only a few of the more striking will here be selected.

Hurdwâr is a town in Northern India at the base of the Himalayas, where the Ganges begins its course in the plains. It is the seat of a great Hindoo pilgrimage, which takes place annually in April, when sometimes from 2,000,000 to 3,000,000 of people occupy an encampment of about twenty-two square miles, comprising a low flat island in the Ganges and the opposite banks of the river. Bathing in the sacred stream on a certain day is the main object of the devotees; which day, in the year 1867, fell on the 12th of April. The bath was taken early in the morning. From noon on that day the pilgrims began to disperse so rapidly that on the morning of the 15th the encampment was quite deserted. It appears that up to the former date the health of the encampment was excellent, and it was the opinion of the reporter (Dr. Cunningham) that cholera was introduced into the camp by pilgrims from the neighboring districts going late to the fair. He believed that the cholera excreta may have been buried in the trenches and carried by a heavy rain into the river, and there swallowed by the pilgrims; for to drink of the water of the Ganges as well as to bathe in it is a religious obligation.

Immediately after the breaking up of the camp cases occurred in the surrounding districts, the epidemic widening in all directions. The pilgrims were almost always the first persons attacked in any locality, and the cholera attended them on their route wherever they went. In all the districts where the disease prevailed no cases occurred until ample time had been given for the pilgrims to reach them. In a word, "the cholera first showed itself among them; it followed their lines of route only, and did not outrun them; their progress was its progress, and their limits its limits." The mortality caused by this epidemic among the whole civil population of the North-western Provinces of the Punjâb has been estimated at about 117,181. The history of the religious festival of 1879 {724} was identical with that just sketched, except that the number of the pilgrims was smaller and the deaths proportionally less.

Out of the numberless illustrations of the manner in which cholera is disseminated by water the following may be cited: In 1865 about 100,000 pilgrims were assembled at Mecca, of whom from 10,000 to 15,000 fell victims to the disease, two-thirds of them within a period of six days. Some cause acting simultaneously upon the whole number of persons must be admitted to account for so extraordinary a fact, and such a cause is not far to seek. At a certain sacred well "one hundred thousand people had skinfuls of water poured over them at the side of the well, and every one of them then drank largely of water drawn from the well. Much of the water poured over the pilgrims must have found its way by soakage back into the well, and if any of the pilgrims were at the time suffering from cholera, or had cholera-tainted garments about them, the well would be exposed to pollution."

In the cholera epidemics of Zanzibar the disease produced the greatest havoc among the negroes, the Persians, and the East Indians; very few Europeans were attacked, and quite as few of the sect of the Banyans, who drank only water drawn from their own wells. The persons among whom the disease prevailed so fatally used chiefly the water of a certain well which was highly prized, but which on this occasion had become polluted by soakage from an adjacent cesspool into which the dejections of cholera patients had been thrown. It appears, also, that in Zanzibar the streams are very rarely bridged, and hundreds of negroes, in passing backward and forward, wade through them and pollute them. In these streams, also, the negroes wash their clothes and all the foul clothing of the contiguous town. While this business is going on "a gang of negroes may be at work at not many hundred yards' distance filling water-casks for the shipping." Subsequently to the watering of the ships in this manner sailors were attacked with cholera, and others who used water drawn from the stream below the place where it became polluted were attacked, and many of them died; while Europeans living on shore, and who drank the water of the same stream, but drawn from a much higher point in its course and after having been filtered, escaped the disease.

The history of the disease in Europe furnishes a multiplicity of similar cases, and even more distinctly exhibits the dissemination of cholera by contaminated water. In Holland not less than five epidemics of the disease occurred between 1832 and 1869, all of them causing a great mortality, to which the epidemic of 1866 alone contributed not less than 20,000 deaths. This was about 55 deaths for every 10,000 inhabitants. Such exceptional mortality over so wide a territory has been ascribed to the extreme porosity and humidity of the soil, which is nearly all below the level of the sea. Such a soil must necessarily retain longer than other soils whatever it absorbs, and thus tend to render the well-water habitually impure. If, then, to the ordinary impurities a specific {725} poison is added, its characteristic effects may assuredly be looked for. The conditions now stated explain the conclusions of Ballot of Rotterdam, drawn from a study of the several epidemics referred to. They are as follows: "1. Holland is highly affected by the cholera at every epidemic, chiefly in those parts where they drink water directly from the rivers and canals or from ground saturated with sewage. 2. In places where rain-water is generally drunk the disease is far less violent. 3. Places where there is no other drinkable water but rain-water are not affected by the epidemic; the single cases occurring there are imported. 4. When places affected by the cholera were supplied with pure water instead of the vitiated water the disease disappeared." In like manner, we find that the cholera epidemic of 1873 in Germany seemed specially to select those situations where the subsoil was impregnated with decomposing organic matter; and it is evident that, in cities especially, such situations would include the most poverty-stricken districts, while the higher, drier, and at all times more salubrious localities are inhabited by the classes enjoying the greatest material prosperity.

This mode of infection has been traced in numberless individual cases of cholera. In London there was a certain well into which the liquid contents of a sewer had been percolating for months. Of the water of this well hundreds of persons had been drinking without obvious injury. At last a case of cholera occurred hard by; the discharges were thrown into a privy which communicated with the sewer and indirectly with the well, whereupon more than 500 persons who drank water drawn from that particular well were attacked with cholera within three days. So in 1856 cholera prevailed in the county jail of Oxford, Eng., the drain from which emptied into a pool from which the water was drawn to supply the city prison. In the latter institution cholera began to prevail, but declined as soon as the pipes conveying the water were cut off, and soon afterward ceased entirely. Again, in Constantinople in 1865 the clothes, mattrasses, etc. of cholera patients were washed at a fountain the basin of which was divided into two parts by a wall; one part was used for washing clothes and the other for drinking purposes. Unfortunately, the waste-pipe of the former being obstructed, the foul water of one side communicated with the clean water of the other, and in one day 60 people died of cholera in the small portion of the city which was supplied from the infected source. The striking case has often been cited which occurred at Epping, Eng., where a woman brought the disease from a distance into a perfectly healthy house and neighborhood, and of ten persons affected with it seven died, including a physician in attendance upon one of them. An examination of the premises "discovered, below the pipes leading from the water-closet and from the eye-hole of the sink through which the choleraic dejections had been passed, a leakage which extended under the foundations of the building and entered the well. The sewage was distinctly traceable on the side of the well corresponding with the leakage in the drain." After this discovery and the disuse of the foul water not another case occurred. In 1868, Dr. {726} Farr, in his History of the London Cholera Epidemic of 1866, showed that water into which cholera dejections find their way produces cases of cholera all over the district in which it is distributed for a certain period of time, and that if the distribution is in any way cut short the deaths from cholera begin to decline within about three days of the date at which the distribution is stopped.

Analogous instances are furnished by every cholera epidemic of which the history has been accurately observed, including that which extended so widely over the United States in 1873. Most of the following are cited from the official reports prepared, under the direction of the Surgeon-General of the army, by Surgeon Ely McClellan and Dr. John C. Peters. Several of the first cases, however, are foreign.

In 1861, at a station in India, some fresh cholera dejecta found their way into a vessel of drinking-water. Early on the following morning a small quantity of this water was swallowed by nineteen persons, five of whom were attacked with cholera between the first and the third day afterward. In 1876 an outbreak of cholera took place in a village in Hindostan, which followed the arrival of wedding-guests, one of whom was attacked, and from whom it rapidly spread. The soiled clothes of one or more of the patients were washed in a pool from which all the villagers obtained their drinking-water, and on the discontinuance of this source of water-supply cholera speedily diminished in frequency and fatality. In the German epidemic of 1873 many cases occurred where persons deriving their drinking-water from special sources were attacked with cholera, while their neighbors, supplied from a different source, remained free. Again, it has frequently happened that outbreaks of cholera have been checked by the prohibition of the suspected water and the substitution of a pure supply. It seems probable that a very small portion of cholera discharges suffices to infect a very large body of water and maintain its infectiousness for a considerable time.

In December, 1871, an outburst of cholera occurred which was confined to the inmates of three excellent houses in a fine block of buildings in Calcutta. There had been no cholera in that neighborhood for four years. Within forty-eight hours a majority of the lodgers were sick, and on investigation it was found that the disease was carried in the drinking-water and in the milk diluted with it. The particular locality in which Dr. Koch made the discovery of the microscopic representative of cholera furnishes an example of the same nature: "At Saheb Ragau, a locality which has repeatedly been visited by cholera during the last hundred years, numerous cases of the disease were reported, and these, on inquiry, were found exclusively in the huts situated round a certain tank. Of the few hundred people who dwelt in these huts, as many as seventeen died of cholera, though the disease was not at that time prevalent in the neighborhood, or indeed in the whole police district of Calcutta. It was proved that, as usual in such cases, the dwellers around the tank used it for bathing, and drew thence their drinking-water; it was also elicited that the linen of the first fatal case, befouled with cholera dejections, had been washed in the tank." In June, 1873, a new {727} hotel was opened at Vienna, and many of the guests became affected with diarrhoea that was attributed to the drinking-water, which was offensive to the taste and smell. After a fortnight a gentleman died of cholera in the hotel, and two days later several of the guests were attacked with the disease, of whom fourteen died. The gentleman who first died was believed to have brought the poison with him into the hotel, so that the drinking-water, which previously had been polluted with ordinary fecal discharges, became specifically affected through him. The discharges of one ill of cholera were thrown into, and the vessels used by him were washed near, a well from which all the residents of a farm-house drank. The wooden curbing of the well had rotted, and the ground immediately around had sunken; a heavy rain burst the curb, overflowed the well, and washed into it the entire surface-drainage of the surrounding ground. No attention was paid to this, and the water was used as before. It became so offensive that its use was forbidden, but too late to save the family, nine of whom died of cholera.

At Farmington, Tenn., a man arrived who had contracted the cholera at Nashville; his illness ran its course at a point just forty paces from a well. Families that obtained their water from this well suffered in nearly all their members; where only certain members drank of it, they alone were affected. At Huntsville, Ala., during an epidemic of cholera, the city authorities forbade the use of well-water, and supplied pure water from another source, but only for one week. During this time no new cases of the disease occurred, and the negroes, thinking themselves secure, resumed the use of the well-water, and within four days six fatal cases of cholera occurred in the vicinity. The use of the well-water was again prohibited, and again the progress of the disease was arrested.

It has already been intimated that the cholera poison may be diffused through the air from either moist or dry sources, and especially from contaminated clothing, and then be taken into the throat and swallowed. Dr. Richardson refers to a local epidemic in England in which "the persons most constantly and fatally attacked were the women who washed the clothes of the sick;" and this circumstance has been largely confirmed by other observers. In a village not far from Marseilles, and in an isolated place, a peasant and his wife who had not left the country sickened and died of the disease. The woman, who was a laundress, had received a bundle of linen belonging to a person recently arrived from Egypt, and the husband opened the bundle and unfolded the pieces. During the Crimean War many of the washermen attending to the washing of the French hospitals were attacked by cholera. In the post-office at Marseilles none of the clerks who handled the outgoing mails were attacked, but of those who sorted the mails coming from the East, where the disease prevailed, one after another suffered from cholera.

The cholera was introduced into Guadaloupe by clothing contained in a trunk belonging to a person who died on the voyage thither from Marseilles, where the cholera then prevailed. The woman who washed the clothing died, with all her family. Attracted by the circumstances of {728} the case, many came to her house, and of these several died. From this point the disease spread over the island. A sailor died at some port in Europe of Asiatic cholera in 1832. A chest containing his personal effects, clothing, etc. was sent home to his family, who lived in a small straggling village on the Atlantic coast of the State of Maine. It reached them about Christmas, and was opened on its arrival. The inmates of the house were all immediately and suddenly seized with a disease resembling Asiatic cholera in all its malignity, and died. There had been no cholera in the State. The last case of cholera that occurred in the garrison at Malta in the epidemic of 1865 was that of a woman who had stolen a chemise the property of one who had died of the disease. She put on this fatal garment, probably soiled with cholera discharges, and certainly unwashed, many days after the death of its former possessor; she took the disease and died.

It is sometimes said, and oftentimes repeated, that cholera is not directly contagious--is not communicated by the sick to the well. No statement could be more unfounded. The whole history of cholera proves that the physicians and nurses of cholera patients are often affected by the disease. "In Constantinople no less than twenty-seven physicians and medical assistants were attacked and died during their attendance on cholera patients; and in Paris and Toulon similar results followed. At Halifax, N.S., two of the physicians who volunteered in aid of the steamer England, which put in there disabled by the ravages of cholera among the officers and crew, as well as among the steerage passengers, took the disease, and one died" (Read). In 1832 the cases of cholera in Edinburgh were in the proportion of 1 to every 1200 of the population of the city, while among those in attendance upon the sick the proportion was 1 to 5. In 1848-49 one-fourth of the nurses employed in the cholera hospital took the disease, while in the general hospital, only a few paces distant, where no cholera patients were received, not a single attendant was attacked. In the London Hospital, in 1866, none of the medical officers, volunteer nurses, or sisters were attacked. Of the (regular) nurses five contracted the disease, and of these four died. In 1849 a severe and fatal epidemic broke out in the Philadelphia Almshouse. The resident physicians of the hospital were abundantly occupied with the care of the sick of other diseases, and it was thought prudent not to allow any, even an indirect, communication between them and the cholera patients. The latter were therefore removed to an isolated building in the middle of the quadrangle, and attended by physicians from the city who had volunteered their aid. Three or four of these physicians had attacks of cholera, and two of them died. At this time there was no cholera at all in the city, and the young physicians could not have become infected outside of the almshouse. They were attacked while attending the sick of cholera, but the regular house-physicians, who seldom visited the cholera patients, escaped altogether.

The importance of recognizing the communicability of cholera is so great that no apology need be made for introducing the following additional illustrations of it furnished by Griesinger in his article on the dangers of cholera to medical men. They are the more important because {729} in many other instances cholera physicians have suffered little for their devotion to duty: "At Moscow, in 1840, hospital attendants contracted the disease to the extent of 30 or 40 per cent., while in the general population only 3 per cent. were attacked; at Berlin, in 1831, in Romberg's hospital, 54 out of 115 persons were attacked: in 1837 one-fifth of the attendants took the disease, and on one occasion no less than seven of them fell ill on a single day. In La Charité Hospital in Paris, in 1849, one-sixth of the attendants had the disease, while only one-twenty-fifth of the general population of the city suffered from it; at Mittau, in 1848, one-half of the physicians took the disease; in 1842, at Toulon, ten health officers out of thirty-five were ill with cholera, and five of them died, while of thirty workmen who were employed to carry the dead bodies one-third succumbed; at Stockholm, in 1853, of 536 attendants one-eighth took the disease, and half of that number died; at Vienna, in 1854, out of thirty-six nurses, seven caught the disease, and seven men employed in removing the dead became affected with a prolonged and exhausting diarrhoea; in 1849, at Strasburg, five nurses out of ten were attacked, etc." ... "Physicians, nurses, students, etc. are less frequently affected, however, than patients ill with other diseases who are lying in the wards where cholera patients are treated, and are therefore more constantly exposed to the emanations from the discharges; and physicians usually suffer less than the attendants who are constantly waiting on the cholera patients."

It may be added that Surgeon-General John Murray, who served continuously for thirty-eight years in British India, caused upward of five hundred circulars to be addressed to the local governments and filled up by the local medical officers. From these returns it appeared that the belief in the communicability of cholera, in one way or another, was practically unanimous; for of the whole number, those who believed that it is conveyed from person to person were 75 per cent.; from place to place, 85 per cent.; through the atmosphere, 80 per cent.; with the drinking-water, 85 per cent.; by the evacuations, 92 per cent.; and by clothing, 98 per cent. This gentleman has more recently furnished additional facts supporting the same conclusion. For example: Out of fourteen cases that occurred at Ramleh during the Egyptian epidemic, eleven occurred in patients already in the hospital for other diseases. In 1856, after visiting the dead-house where the bodies of fourteen cholera patients lay, as he entered the cholera ward he felt a sudden shock in the epigastrium, followed by a deadening sensation that rapidly spread over the whole body. On another occasion he saw a clergyman who was talking to a cholera patient suddenly seized with vomiting of a watery liquid. Several analogous instances are related by him.

It has been objected to the communicability of cholera that its dissemination does not always follow the deposit of cholera discharges in privies, wells, etc., and also that when infection does take place, it may occur between remote extremes as to time, and therefore cannot be attributed to infectious germs. Such objections are frivolous, because we know nothing of the nature or vitality of cholera-germs, and they are, moreover, drawn from exceptional cases. The power of infected fomites to develop {730} the disease has been preserved, in a journey from Arabia into Africa, for at least twelve days, and for even a longer period in passing from Germany to Chicago, as already related. It is true of every infectious and contagious disease that it may possess one or both of these qualities in various degrees--that at one time it is only exceptionally communicated, and that at another time it appears to propagate itself virulently. So the phenomena of cholera may consist of little more than a watery diarrhoea, which may be so mild as hardly to disable the patient from working, while at other times the attack may include all those terrible and fatal symptoms which have won for the disease the name of malignant. That a certain quantity, or "dose," of the cholera poison is required to develop the disease, but one that varies considerably in different cases, may be inferred from these facts: 1. Out of a certain number of persons equally exposed to receive the disease, only a portion may be attacked at all, and these in very unequal degrees. 2. Persons so slightly affected as to be ignorant of the nature of their sickness, and believing it to be an ordinary diarrhoea, may nevertheless become the innocent, because ignorant, disseminators of cholera. The explanation of such facts may be manifold: they may depend upon the dose or upon the energy of the morbid poison, on various possible conditions of its recipient, and so on; but, however explained, their reality is none the less certain. The receptivity of persons exposed to the contagion of cholera is very different. It is well known that some persons appear to be proof against other contagious diseases, while others seem never to acquire an immunity from them. On this very important point the conclusions of Fauvel directly bear. They include the following propositions: The East Indian ports where cholera exists as an endemic disease are never the seat of an extensive epidemic among the native population. But strangers to these localities are liable to the disease, and such are the Mussulman pilgrims who come to Bombay to take ship for Mecca. A severe epidemic of cholera confers upon the locality in which it has taken place an immunity which in India appears to be of several years' duration. Such an epidemic in any country is a proof that the cholera is not endemic there.

If a contagious disease preserved its virulence undiminished, it might continue to prevail indefinitely. But we know that all other contagious epidemics do come to an end sooner or later, and hence we must conclude that their specific cause progressively loses its virulent qualities. There is every reason, therefore, to believe that the same is true of cholera. Its communicability, and therefore its diffusion, may vary with climatic, seasonal, local, personal, and other conditions; but of what nature those conditions are, and especially of the last and most important, the personal, hardly anything is known. Nor need we too curiously investigate them, so long as the fact remains that outside of, and independent of them all, there is but one essential cause of cholera--a morbid poison as specific in its nature as that of any of the eruptive fevers--a poison which no determinable conjunction of circumstances has ever engendered, and which was unknown in Europe and America before it was carried to them from India. In just such a way did small-pox first arise in the Western World. It had never appeared in Europe until the latter part of the {731} sixth century, when for a short time it prevailed in Marseilles and the neighboring country. Afterward it was not heard of until it was reintroduced by the Crusaders on their return from Palestine in the twelfth century, since which period it has hardly ever ceased. The history of the diffusion of cholera is closely analogous to this in several particulars, and we may reasonably expect that what was in the last generation a new disease will henceforth be liable to prevail again and again as the intercourse increases between the nations of the West and the immemorial source of cholera in Hindostan.

In the preceding discussion of the origin and dissemination of cholera the broad facts of its specific nature and its contagion by means of excreta have been chiefly insisted upon. Little has been said either of the nature of the contagium or of the conditions that modify its activity. These points will be considered hereafter. But it is proper in this place to state that, in the opinion of most investigators, the contagious element has the power of multiplying itself, not only within the body, but wherever it is in contact with decomposing organic matter, provided that the degree of heat and amount of moisture present are adapted to promote such a change, which is certainly analogous to fermentation, if not identical with it. And the facts already mentioned may be recalled, which show that the contagium cannot be a light and subtle substance, since, as has been stated, the immediate attendants upon cholera patients are not as apt as might be expected, on that hypothesis, to contract the disease, while washerwomen inhaling, and probably swallowing, the moist fumes from cholera fomites much more frequently do so; that fomites saturated with the dried discharges are very infectious; and that water is the principal vehicle by which cholera-germs are carried into the stomach.

SYMPTOMATOLOGY.--Like other diseases, cholera occurs under very dissimilar aspects and with various degrees of gravity. Like those especially which are caused by specific morbid poisons, it may be so insignificant as to escape recognition, or, on the other hand, it may give rise to violent and distressing symptoms which come on without warning and hurry the patient to inevitable death. Whenever epidemic diseases present such opposite extremes of severity in their symptoms, it may reasonably be inferred that the differences depend mainly upon the quantity of the poison that has been received into the system, precisely as the dose which has been taken of a narcotic or acrid poison may be estimated by the gravity of its effects. Individual peculiarities, constitutional or acquired, may modify the characteristic phenomena, and sometimes a careful inquiry may be necessary even to detect their existence; but a study of cholera in all its grades shows that its symptoms are all the effects of one and the same cause, and that the cholera poison acts primarily upon the gastro-intestinal mucous membrane. It follows, as a matter of course, that, being thus applied, it will occasion symptoms differing in degree and in kind according to the energy of its action, and that this, again, will depend partly upon the inherent virulence of the agent and partly upon its quantity. In fact, this feature in the clinical history of the disease can be explained only by the operation of a special irritant acting with different degrees of power upon the gastro-intestinal {732} mucous membrane. In other words, the different forms under which it is convenient clinically to recognize and describe cholera are nothing more than different degrees of the operation of one and the same poison, modified more or less by the peculiarities of individual patients. In the most typical of the fully-formed cases of cholera there is a stage of diarrhoea, a stage of cholera morbus--i.e. of vomiting and purging--with more or less evidence of stagnation of the blood, which is followed either by reaction and recovery or collapse and death. The phenomena of those several stages will now be described, after which certain symptoms will be more particularly considered.

It has more than once been pointed out that, however mild an attack of cholera may be, the dejections accompanying it are infectious, and may produce in other persons the gravest types of the disease. Hence the importance, not only to the patients, but also to others, of recognizing it in the earliest stage; for while this knowledge may suggest measures for preventing an extension of the disease, it leads to the prompt use of remedies at the only period in which their success can at all be counted upon. The characteristic of this stage, which has generally been called either choleraic diarrhoea or cholerine, is a diarrhoea remarkable for its profuseness and the frequency and serous quality of the stools, which are, however, of a more or less yellow color. They are preceded by rumbling and gurgling noises in the abdomen, are voided without colic or tenesmus, and are followed by a remarkable sense of exhaustion or faintness, which is sometimes also accompanied with nausea, and, if they are very frequent and copious, cramps are apt to be felt in the calves of the legs. In this variety or stage of the attack, as a rule, there is not any vomiting; there is complete anorexia, but urgent thirst, a white and clammy tongue, and a peculiar alteration of tone, a huskiness, faintness, or hoarseness of the voice. The stools vary from six to twelve a day, and, as above stated, are slightly yellow; they are also alkaline, and on standing deposit a granular sediment which consists largely of the débris of intestinal epithelium. Unless the attack is very severe the temperature is not lowered by much more than 1° F. The symptoms now described, especially in their milder grades, may last for a week or even longer, and then, according to circumstances, end either in cure or in fully-developed cholera; but under appropriate treatment they usually subside in a day or two, and more or less rapidly according to the degree of damage done to the digestive mucous membrane.