# Popular Science Monthly/Volume 55/September 1899/Are We in Danger from the Plague?

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APPLETONS’
POPULAR SCIENCE
MONTHLY.
SEPTEMBER, 1899.
* ARE WE IN DANGER FROM THE PLAGUE?
By VICTOR C. VAUGHAN,
PROFESSOR OF HYGIENE IN THE UNIVERSITY OF MICHIGAN.
IN an article on the plague in this journal, in May, 1897, the writer answered this question as follows: "Yes, there is danger; but this, being foreseen, may be easily avoided. Thorough inspection of persons and disinfection of things from infected districts will keep the disease out of Europe and America. Only by the most gross carelessness could the plague be permitted to enter either of these continents."
It will be of interest to take up this subject again, and study it in the light of the history of the plague since the article referred to was written. The plague first appeared in western India, at Bombay, where it still prevails. We are without any exact information concerning its introduction into that city. Before the outbreak of the disease at Bombay the mortality had increased so markedly that it was a subject of discussion for three meetings of the Grant Medical Society. The increase was attributed to the filthy condition of the streets. This society made an investigation of the increased mortality, and presented a report on the same to the municipal authorities. Instead of heeding the warning, the authorities jeered at the society, and refused to allow the report to be read.
Dr. Viegas appears to have been the first physician to recognize the existence of the plague in the city. In a paper read before the Grant Medical Society on November 24, 1896, he discussed the possible and probable avenues by which the disease had found its way into the town. He stated that sugar and dates had ​been mentioned as means by which the plague was imported, but, if this had been the case, he thought it strange that the infection had not been conveyed from Bagdad and Bassorah, inasmuch as these articles come almost exclusively from those places. Again, it was thought possible that the clothes of the sick or of the dead from the plague in China might have been brought over to Bombay, but Dr. Viegas was unable to find any evidence in support of this theory. It had also been claimed that rats sick with the plague had come by ship from Hong Kong, and had infected the rats about the docks in Bombay. This theory, Dr. Viegas held, was not supported by any facts. In short. Dr. Viegas found some objection to every theory that had been proposed, and leaves us in doubt as to his own views concerning the avenue by which the plague reached Bombay. He is quite confident, however, that the filthiness of the city is to blame for the rapidity with which the disease spread.
In a report by Lieutenant-Colonel Weir on the plague in Bombay a statement is made that the disease was imported from Suez. Early in September, 1896, four very suspicious deaths were reported, but, as none of these had been attended by medical men, no definite conclusion could be reached concerning them. The first case was reported by Dr. Viegas late in September, 1896. The patient was a native who had not been out of the city for months. The first case reported among Europeans occurred on November 12, 1896. During the winter of 1896 and 1897 the disease prevailed most alarmingly, and reached its highest mortality during the week ending February 9, 1897, when the deaths from all causes in Bombay numbered 1,891. During the summer of 1897 the disease declined, and led to the belief that the measures that had been put in operation would prove successful. This hope, however, was not realized, and during the winter of 1897 and 1898 there was a recrudescence of the disease. During the summer of 1898 the disease again abated, to appear with renewed strength during the winter of 1898 and 1899. During the last week in March, 1899, the total number of deaths from all causes in Bombay reached 2,408, and the deaths from plague alone numbered more than 250 a day. It will be seen from these figures that the plague still rages with undiminished virulence in the capital of western British India. The abatement of the disease during the summer months and its increased severity during the colder season are not directly due to the effects of temperature. In the warm season many of the natives sleep out of doors, while during the colder weather they crowd into small, unventilated, filthy rooms. It is the opinion of practically all observers at Bombay that the recrudescence of the disease during the winter is due to this overcrowding.
​Since the plague has prevailed at Bombay for nearly three years, it may be well to inquire concerning its probable continuance at that place. In making this inquiry we may learn something of the sanitary condition of the city and the habits of its inhabitants. Bombay is the metropolis of western India, and is situated on a long, narrow island running almost north and south. The city is located near the southern end of this island, with its harbor to the east and its sewage outfall to the west. Its population of about nine hundred thousand is a very mixed one, consisting of Hindoos of different castes, of Mohammedans, of Eurasians, and of Europeans. Differences in race, in religion, and in caste make it exceedingly difficult to carry out sanitary measures and to look after the sick. The mean temperature is about 79° F., and the relative humidity seventy-seven per cent. A considerable portion of the island is below high-water level, and consequently the sewage must be removed by means of pumps. The mean maximum temperature of the ground eleven feet below the surface is 84.9° F., and the mean minimum temperature is 80.9° F. It will be seen from these figures that organic matter must undergo rapid decomposition both on the surface and in the sewers. The water supply, which is said to be excellent, is so carelessly drawn upon by the natives that, although sufficiently abundant if used properly, it sometimes becomes scant. It not infrequently happens that the sewers will not carry the volume of water turned into them. For this reason, together with the tropical rains, the soil often becomes water-logged. Indeed, the surface in some sections of the city may be, not inappropriately, compared with a fermenting muck-heap. Besides the fixed population, there is a constant current of people flowing to and fro between the island and the mainland. When there is any opportunity for the employment of a large number of unskilled laborers, hundreds and thousands from the surrounding country pour into the city. These people know nothing of sanitary appliances, they lodge in the most densely crowded parts of the city, and often a dozen of them will hire a single room, not more than ten feet square, in which they eat and sleep. It is said that seventy per cent of the inhabitants of Bombay live in "chawls." These are tenement buildings of from five to seven stories high, built on the "flat" system. A narrow hall, at the end of which is a latrine, runs through each story, and from this doors open into rooms eight by twelve feet in area. In one of these houses from five hundred to eight hundred people live. These buildings are crowded together, with only narrow, dark alleys between. Into these alleys the inhabitants of the houses on both sides throw all kinds of refuse. In many parts of the city fecal matter is deposited in boxes or ​baskets, and these, when filled, are carried on the heads of scavengers to certain designated places and the contents dumped into the sewers. It may be of interest to note, in passing, that these scavengers seem to be largely immune to the plague and all other infectious diseases.
This is a brief description of the sanitary condition of the city into which the bubonic plague found its way nearly three years ago. How long is it likely to remain? Before attempting to answer this question we might ask what means have been employed to eradicate the disease. On October 6, 1896, the municipal health commissioner issued an order to the effect that all cases of the plague were to be segregated, their houses disinfected, by force if necessary, and their sick to be taken to the hospital. Health inspectors visited all parts of the city, and carefully went through the great tenement houses looking for those sick with the plague. When such were found they were immediately sent to a hospital. Later, four camps were prepared, with facilities for accommodating about twenty thousand people. An attempt was made to transfer all the residents from a certain section of the city to these camps, and detain them there while their residences were being disinfected. After this had been done these people were allowed to return to their homes, and another twenty thousand were taken to the camps. This attempt, however, was never fully carried out. A high-caste Hindoo prefers death at any time to association with one of inferior caste. Every attempt at segregation of the sick led to more or less disturbance; and finally, in March, 1898, serious riots resulted. These were begun by Mohammedans, who followed a medical officer to the hospital and burned the building and hospital supplies. A plague inspector and three English soldiers were stoned to death. Since the riots attempts at segregation of the sick have been practically abandoned. Numerous hospitals have been provided, in order that those differing in religion or in caste might be cared for at different places. Under certain restrictions those sick with the plague are allowed to remain in their homes. It will be seen from these statements that it is not probable that the plague will be driven by human agency out of Bombay. The Hindoos believe that when the plague finds its way into a city it will remain for six years. The probabilities are that this belief will be strengthened by the history of the present epidemic in Bombay. Nothing short of an extensive conflagration, destroying a large part of the city, can thoroughly disinfect this place, in which the plague has already dwelt for nearly three years. I think, therefore, that we must conclude that it is quite certain that for several years yet Bombay will remain an infected city.
​When the plague was first announced at Bombay a large number of its inhabitants, estimated at about three hundred thousand, left the city. There can be but little doubt that with these the germs of the plague were carried into the surrounding country. From Bombay the disease has spread out in every direction, until it has found its way into nearly every part of India. To-day the three large commercial cities of British India—Bombay, Calcutta, and Madras—are all infected. The manner of the introduction of the disease into Calcutta is somewhat uncertain, several different accounts being given as authentic. Dr. Cantlie says on this point: "The first case dealt with and reported upon in Calcutta gives an interesting history. The patient, a lad seventeen years old, came from Bombay, where evidently he had been exposed to infection, as his sister, who accompanied him, had seen several cases of plague in Bombay. Fifteen days before leaving Bombay he had noticed swelling first in one groin and then in the other, but never felt ill until his arrival in Calcutta, on September 24th. He was seen and carefully examined in Calcutta by honest observers, and a diplobacterium identical with the Kitasato bacillus was found in his blood. Not only so, but the clinical symptoms of plague were most manifest."
Another authority would have it that the plague was brought to Calcutta from Hong Kong by a British regiment which had been engaged in cleansing infected houses at Hong Kong. On this point Dr. Simpson makes the following statement: "In January, 1895, the regiment went to Calcutta, and this disease was first diagnosed as syphilis, then as malarial fever with bubo, and finally the cause was declared to be unknown. In June, 1896, one of the medical officers of the regiment was attacked with fever, and the glands of the neck, axilla, and groin were all enlarged. A goodly number of similar cases were met with in the town; moreover, the rats became sick, and the grain stores swarmed with diseased and dead rats. In spite of opposite evidence, it was well-nigh certain that plague in a sporadic form had been in Calcutta since 1895 or 1896." The bacillus of the plague has undoubtedly found Calcutta quite as well prepared for its reception as Bombay. In discussing a medical report on the sanitary condition of Calcutta, the Pioneer Mail makes the following statement: "London, with its population of over 4,000,000, has about 36,000 people to the square mile. In the thirteen wards of Calcutta there are only four below this figure; the remainder have from 46,000 to 144,000 per square mile, three wards containing actually over 100,000. Colootolah is most densely populated; the houses are literally crammed with people. One case is quoted where 250 persons were living in a space that should ​accommodate only 50. In a hut seven feet in length, breadth, and height five men were found, and several instances are given where similar conditions obtained. In our barracks 600 cubic feet per man is the minimum space allowed. In these bastis the space runs from 157 to 49 cubic feet. This would be bad enough if everything were clean and sweet in and about the huts, but, as the medical board puts the case, 'here we find an allowance per head going as low as practically one thirtieth of that given in barracks, and no ventilation, with filth ad libitum both in the room and in its surroundings, to say nothing of the filthy persons of its occupants, the sewage in the adjacent drains, and the accumulated filth in the neighboring latrines; and to this may be added the fact that the subsoil on which the huts are built is soaked through and through with sewage matters and littered with garbage and filth of all kinds.' The narrow gullies which give access to these huts are in keeping with the general character of the bastis, and we may well wonder that epidemic disease is not always present."
The probabilities are that the plague will continue in Bombay, Calcutta, and Madras until it dies out from want of susceptible material. It is not at all likely, with the conditions in these cities, such as have already been described, that sanitary measures sufficiently energetic to destroy the bacillus will be resorted to. For some years to come these cities are likely to harbor the infection, and will remain, as they are now, nurseries for the disease.
The plague has not confined itself to the large cities of India, but has spread all over that country. It has extended into the northwestern provinces, has crossed the frontier, and passed into Baluchistan and Afghanistan. In many of the interior cities it has proved quite as fatal, in proportion to the population, as at Bombay and Calcutta. At Poonah the mortality has during some weeks been as high as eighty per cent of the cases, and four hundred deaths a week have been reported. At Sholapore, in the Punjab, far to the northwest of Bombay, the disease has prevailed in epidemic form.
With the plague widely diffused over the Indian empire, what measures have been taken to prevent its spread to other parts of the world? There are two routes by means of which the disease may pass from India to Europe. One of these is by ship through the Red Sea, the Suez Canal, and the Mediterranean; the other is overland from the northwestern provinces of India through Afghanistan into southeastern Europe. In fact, there are three overland routes from northwestern India into Europe. One of these leads from Lahore, the capital of the Punjab, through Afghanistan into the Transcaspian Province of Russia. The Trauscaspian ​Railway extends from Samarkand, a place of about thirty-five thousand inhabitants, through the desert to the Caspian Sea at Ouzoun Ada. The latter place is connected by steamer with Baku and the Russian railroad system. The second overland route starts from the northwestern provinces, or Afghanistan, or Baluchistan, passes through Persia, extending on up between the Caspian and Black Seas, and crosses the Caucasus Mountains in the neighborhood of Tiflis. Both of these routes are quite extensively traveled and pass through cities of considerable commercial importance. Samarkand has extensive manufactures of cotton and silk, and carries on considerable trade by means of the Transcaspian Railway with European Russia. The second route passes through Teheran, the capital of Persia, with a population of about two hundred and twenty-five thousand. This route is also largely employed by commercial travelers, especially from Russia. The third overland route passes through Persia and Turkey in Asia up to Constantinople. This route can not be called a commercial highway, but it is used to a considerable extent, especially by pilgrims, and since at no point do travelers along this route come in contact with European guards against the plague, it is most likely that the pest will find its way into Constantinople by this avenue, if at all. The first two overland routes are guarded by Russian medical inspectors. Russia has not been slow to protect itself against the introduction of this epidemic. In December, 1896, the following lines of action were determined upon, and have apparently since that time been carried out quite thoroughly: First, Russian medical men were sent to the larger cities of Persia, such as Teheran and Meshed, for the purpose of watching the approach of the plague. All Russian consular officers in Persia were requested to inform these medical men of every rumor of the epidemic. Second, points of embarkation on the Persian shore of the Caspian Sea have been watched, in order to detect suspicious cases that might pass to Russia along this route. Third, observation stations have been established along the frontiers of the Transcaspian Province. Inspection officers stationed at these places have been notified to close the frontier, with the exception of certain points where inspection stations have been established. Fourth, inspectors have also been placed to guard the region of Tiflis against the introduction of the plague from both Persia and Turkey. For the reasons above mentioned, it seems to me probable that if the plague reaches Europe, it will likely do so by way of Turkey in Asia, across the Bosporus into Constantinople. The large number of pilgrims passing along this route, with the Turk's well-known fatalistic belief, render it quite probable that infection gathered anywhere along the route ​may be carried into Europe. Since several places in Hedjaz, along the eastern shore of the Red Sea, have already become infected with the plague, it is by no means improbable that the disease may find its way into the Balkan Peninsula. There are also several centers of infection along the shores of the Persian Gulf. It will be seen from these statements that Mohammedan pilgrims are exposed to the infection. Indeed, already the disease has been detected among these pilgrims on steamships in the Red Sea.
Certain international measures for the restriction of the plague were formulated at the Sanitary Convention of Venice in 1897. Nearly all civilized nations sent representatives to this conference, and certain general rules were adopted. Recognizing the fact that Mohammedan pilgrims from infected districts in India, coming to Mecca and other places along the eastern shore of the Red Sea, would mingle with those of like faith from Turkey and northern Africa, special rules concerning pilgrims were adopted at this conference. It should be understood, however, that these rules are likely to prove efficient safeguards only among those pilgrims who travel by sea. In the first place, the conference made certain regulations concerning the construction and sanitary arrangements of pilgrim ships. The upper deck must be kept clear for these people, and on the main covered deck every pilgrim has to have at least sixteen square feet of surface. Every one embarking on a pilgrim vessel must pass a medical inspection. No sick person or one suspected of having an infectious disease is allowed to go on board. The number which the vessel is allowed to carry is determined beforehand, and the names of all passengers and their home residences are recorded. The ship must supply wholesome water and make provision for food, proper in quality and sufficient in quantity. Every vessel carrying pilgrims must have on board a medical officer and a disinfecting stove. Details are given concerning the sanitary regulations during the voyage. All pilgrims are landed on the island of Camaran, in the Red Sea, before being allowed to disembark on the last stage of their journey. The period of detention from healthy ships at this place extends through only three days. If no disease appears during this time, the pilgrims are allowed to embark again, and go directly to Jeddah. If disease appears either before or after landing at Camaran, the pilgrims are detained at least ten days from the date of the last case. Arriving at Jeddah, they are no longer under international sanitary regulations, and any control exercised over them at that time must be administered by Turkish authorities. Just here, in my opinion, lies the greatest danger so far as pilgrims are concerned. It is true that the conference made certain recommendations and ​formulated certain rules concerning the return of those pilgrims going to the north or into Egypt, but the fact must not be overlooked that these restrictions are applicable only to those who go by sea. No restrictions are placed upon Mohammedan pilgrims returning from Mecca to India. India is already so generally infected that such restrictions have been deemed unnecessary.
The following is a general statement of the rules applicable to vessels coming to European ports from India through the Suez Canal: All vessels that have been ten days or longer at sea after departure from an infected port are allowed to pass through the canal without question and without precaution. Suspected vessels or those which have been at sea less than ten days since departure from an infected port, and which are provided with a medical officer and a properly equipped disinfecting plant, are allowed to pass through the canal in quarantine. This means that while passing through the canal there shall be no communication between those on board the vessel and those on the land. Other suspected vessels are compelled to proceed to the Wells of Moses for disinfection. Here the passengers and crew are disembarked, isolated for twenty-four hours, and their effects disinfected. At the same time the contents of the ship undergo disinfection. If the plague be found on board, all passengers, as well as the crew, are detained for a period not exceeding ten days. All clothing, the cargo, and the ship itself are disinfected. When a vessel passes through the Suez Canal in quarantine, notice of that fact is telegraphed to the country to which the vessel is going, and it is not allowed to land elsewhere.
Should the plague appear in any European country, the following rules were formulated to prevent its spread: (1) Whenever a case of the plague appears in any country the sanitary authorities of that country must give immediate notice to all other countries represented in the conference. This notice may pass through diplomatic or consular agencies, or it may be sent directly by telegraph. After this the sanitary authorities of the country in which the plague has appeared shall inform other countries at least once a week concerning the progress of the disease and the measures resorted to to prevent its spread.
(2) When an infected person enters a country by rail or other conveyance overland, disinfection of his person and personal effects is made obligatory. Land quarantine is condemned, and it is recommended that modern disinfection be practiced in its stead. Each country, however, may reserve the right to close its frontier against any other country in which the disease exists. It is recommended that medical inspection along the frontier be established in ​connection with custom-house examinations, in order to prevent unnecessary delay in travel. Passenger trains and postal cars are not to be detained at any frontier, but if a car be found to contain a real or a suspected case of the plague, this car shall be detached from the train at the frontier or at the nearest station thereto and its contents disinfected.
(3) Travelers coming from infected countries may be, at the discretion of the sanitary authorities, detained under observation for a period not exceeding eight days. Individual governments are allowed to take any special measures that may be deemed wise against the importation of the disease by means of gypsies, vagrants, and immigrants.
In formulating the above-mentioned rules to prevent the importation of the plague into Europe the members of the Venice Congress seem to have been thoroughly convinced that the longest period of incubation possible in this disease is ten days. It seems to have been assumed that if a vessel had been for ten days or longer at sea after departure from an infected port, and no cases of the plague had developed up to that time, there could be no danger of this vessel carrying the infection. It appears to me that a safer course would have been to require inspection of all persons and things going on board a vessel leaving an infected port, and the thorough disinfection of certain things, at least, on such vessels arriving at uninfected ports. The disinfection of a ship and its cargo by means of steam is not at present a very costly procedure.
Since the plague, if it reaches America at all, must come to us by sea, it may be of special interest to inquire concerning outbreaks of this disease on board ship. In making this inquiry we will confine ourselves to such cases as have occurred within the past two years. In March, 1897 (I have been unable to ascertain the exact date), the transport Dilwara left Bombay, bound for Southampton, with a regiment of English soldiers, together with their wives and children. On March 18th, while the vessel was in the Red Sea, a child died of the plague and was buried at sea. On arriving at Suez the persons who had been in immediate contact with the child were transferred to the Wells of Moses and properly disinfected. After this had been done, the vessel was allowed to pass through the Suez Canal in quarantine. No fresh case occurred, and the vessel arrived at Southampton April 6th. Here all articles which might possibly contain infection were disinfected, the passengers were allowed to go to their homes, and the troops were placed in barracks. No other cases resulted.
On July 6, 1807, one of the crew of the Carthage, of the Peninsular and Oriental Company's line, was attacked with the plague. ​The ship was then in the Arabian Sea. Two days later the sick man, with two other members of the crew detailed to attend him, was landed at Aden. Six days later a second member of the crew was attacked with slight symptoms of the plague. This fact was reported when the vessel passed Malta. The Carthage had intended to stop at Marseilles, but, on account of the plague on board, continued its course to England. Both of these patients were isolated by being placed in a large boat hung at a height at the side of the vessel so as to avoid communication with others on the ship. When the vessel arrived at Plymouth the passengers were allowed to depart to their respective homes. The only precaution that was taken consisted in ascertaining the destination of each person, and informing the health authorities of the places to which these people were going. The Carthage had on board a steam disinfector, and everything that had been exposed to the infection was thoroughly disinfected. On arrival at the port of London the second patient was isolated until he recovered. No cases developed in England.
On December 7, 1897, the Caledonia arrived at Plymouth, England, from Bombay, without touching at any Mediterranean port. While in the Red Sea two lascars developed symptoms of the plague. They were landed at Suez, and no further outbreak occurred. When the ship reached Plymouth one hundred and sixty passengers were landed, and their names and addresses forwarded to the local authorities of their respective destinations. After proper disinfection, the ship proceeded to London.
In December, 1898, a case of plague developed on the Golconda while at Marseilles, on her way from Bombay to London. The ship proceeded immediately, the patient was landed at Plymouth, proper disinfection was carried out, and no other cases developed. This is a proof that the assumption that a vessel is safe from infection after ten days have passed since leaving an infected port is fallacious, as this time was exceeded between Bombay and Marseilles.
The report that the Nippu Maru recently arrived at San Francisco with the plague on board has proved to be erroneous.
In September, 1896, a Portuguese-Indian steward died at the Seamen's Hospital, at Greenwich, England, very suddenly. This man was in the hospital for only forty-eight hours, and no one suspected the plague at that time. On the last day of October of the same year another patient in the same hospital was taken ill and died with symptoms of the plague. Bacteriological examinations of the glands of the body of the second man were made, and a bacillus which presented the well-known characters of the plague bacillus was found. The vessel on which the Portuguese steward ​came to England left Bombay about the end of August, 1896. There was at that time no official knowledge of the existence of the plague in Bombay, but it probably existed there. This is another evidence of the fallacy of the belief in the ten days' period of incubation. It seems quite evident to me that the English authorities lay too much stress upon the period of incubation. A man leaving Bombay or any other infected port may carry the bacillus under his finger nails, elsewhere on his person, or in his clothing, and may not become infected until many days after leaving the infected place. Careful inspection and thorough disinfection of all vessels coming from infected ports should be insisted upon. It has been abundantly demonstrated by the history of the plague, as well as that of other infectious diseases, that the old plan of detention in quarantine is a relic of bygone times. Detention is cruel, dangerous, and inefficient; inspection and disinfection are rational and efficacious.
The modes of infection with the bacillus of the plague are as follows: (1) By inoculation. The history of the present epidemic in Asia recounts several instances of inoculation with the plague bacillus. On June 22 or 23, 1896, while making a post-mortem examination. Professor Ayoama, of Tokio, one of the Japanese commissioners sent to Hong Kong to study the plague, scratched the third finger on his left hand; on June 27th he again scratched himself on the end of the right thumb; on the evening of June 28th he felt ill, and had a temperature of 101.6° F.; he slept well during that night, but during the afternoon of June 29th he had a temperature of 105° F. At that time a bubo was found in the left axilla, and there was well-marked lymphangitis of the right arm. Professor Ayoama has described his own case as follows: "On June 28th, after having finished a dissection, I took my meal about half past two and did not enjoy it. After the meal I went upstairs, when at certain movements of the arm I felt a slight pain in the left armpit, and on feeling with my finger I found some slightly enlarged glands present. In the evening I felt very ill, depressed, and languid, burning hot along the whole of the back, while the thermometer showed normal temperature. As Mr. Kitasato and I had invited guests that evening, I was present at supper. I had no appetite, and felt so languid that I often wished to withdraw. At half past eleven I hurried to my room, when I found my temperature was 39° C. I took one gramme of quinine, and slept well. Next morning I awoke and noticed, on the under side of the left ring finger, a small, whitish-yellow blister, and then, along the back of the hand, a red line. From this time I remembered nothing for more than two weeks."
​Dr. Ishigami, another of the Japanese commission in Hong Kong, also inoculated himself with the plague while making a post-mortem examination.
A patient, while delirious with the pneumonic form of the plague, expectorated into the face of an English nurse caring for him. Within a few hours the eye on that side of the face became inflamed; later the parotid and cervical glands became involved, and the nurse died. Other illustrations of inoculation with the bacillus of the plague might be given. Dr. Wyssokowitch and Dr. Jobobat believe that the bacillus can penetrate the unbroken skin. In support of this belief they report some experiments made by them upon macaque monkeys. They found that when a needle was dipped in the culture of the plague bacillus and drawn across the palm of the hand of one of these monkeys, without making any visible scratch, the animal speedily developed the disease. However, this does not prove that the bacillus will penetrate the unbroken skin of man.
(2) By inhalation. That the pneumonic form of the plague results from inhalation of the bacillus can not be doubted. Monkeys caused to inhale the bacillus develop this form of the disease.
(3) By deglutition. That the disease may be acquired by taking the bacillus into the alimentary canal has been demonstrated by experiments upon animals of various kinds.
The sputum of patients suffering from the pneumonic form of the disease is filled with the bacilli. The germs are also found, sometimes at least, in the discharges from the bowels and kidneys. That the infection may be transported in clothing and rags has been long known. The following extract from a memoir by Sir John Hay, then minister from England to Morocco, indicates that the plague was introduced into Morocco in 1826 by means of infected articles of clothing: "The danger from plague by contagion can not, however, to my mind be called in question. That dire disease was introduced into Morocco about the year 1826 by an English frigate, which our Government had dispatched to Alexandria, where the plague was then raging, to convey from that port to Tangier two sons of the Sultan, returning from a pilgrimage to Mecca. No case of plague or other illness had occurred on board the frigate during the voyage, and the Sultan's sons and other passengers were allowed to land at Tangier.
"The customs officers, being suspicious that, in the numerous boxes brought by the pilgrims who had been permitted to embark with the Moorish princes, contraband goods were being smuggled, caused some of the cases to be opened. One contained Egyptian wearing apparel, which the owner said he had bought second hand, ​and subsequently confessed had belonged to a person who had died of the plague in Alexandria. The two Moorish officials who opened the boxes were attacked with the plague that night and died in a few hours. The disease spread rapidly throughout Morocco, carrying off eighty per cent of those who were attacked."
I mention these facts in order to emphasize the desirability of disinfecting all articles liable to carry the infection coming from infected places.
Professor Haffkine's preventive inoculation against the plague is still being largely employed in India. This consists in injecting hypodermically sterilized cultures of the bacillus. No curative action is claimed for this treatment, but it is believed to be protective against the disease. It is stated that more than eighty thousand people in India have undergone this form of vaccination, and that the death rate among these has been exceedingly low. However, it is well to be careful in accepting statistical statements on a matter of this nature. In the first place, it is probable that only the more intelligent will submit to vaccination, and these will also employ other means of protecting themselves against the disease. In the second place, there are many thousands of people exposed to the infection, or at least live in infected districts, who have never been vaccinated and who do not acquire the disease.
Three kinds of serum have been used as curative agents in the plague. In 1896 M. Yersin began the use of a specially prepared serum in China. The first cases treated with this preparation did unusually well, and it was hoped that most valuable results would follow from its more extended use. This serum is prepared after the manner of the antitoxine used in the treatment of diphtheria. That used most largely in India is made at the Imperial Institute of Experimental Medicine in St. Petersburg. Numerous physicians in India have reported upon the action of this serum, and none of them favorably. Very recently Dr. Clemow treated fifty cases with this serum, and compared them with fifty other cases treated without the serum. Every other case was selected for the serum treatment. The mortality was exactly the same in each group, forty patients out of fifty dying.
The second serum is that prepared by M. Roux, of the Pasteur Institute in Paris. This is practically the same as the preparation made by M. Yersin, and the results obtained are equally unsatisfactory. In 1897 the writer had the privilege of observing, both at Paris and at St. Petersburg, the preparation of these agents, from which at that time great results were expected. A third preparation is made by Professor Lustig, of Florence. I have been unable, so far, to find any detailed account of the method followed by ​Professor Lustig in preparing his serum. From all that I can learn, however, it is not a serum, but a sterilized bacterial culture; at any rate, Lustig's preparation has proved probably least valuable of all.
At present (July, 1899) the plague prevails throughout India, and has appeared at various places in Baluchistan and Afghanistan, at Samarkand in the Transcaspian Province of Russia; in Persia, at Bassorah and other points along the Persian Gulf; at several places along the western shore of the Red Sea; at Suez and Alexandria; at Tamatave, in Madagascar; at Port Lewis, Mauritius; at Penang, in the Straits Settlements; at Amoy and Hong Kong, China; and at numerous places in Formosa. For reasons already given, it will not be at all surprising should the recent report that the plague had appeared in Constantinople prove to be true. If it once reaches that place, it is more than likely that it will become scattered throughout the Balkan Peninsula. The sad death of Professor Müller and his laboratory servant, at Vienna, from the plague bacillus which Professor Müller brought from Bombay, shows the necessity for caution in handling the germ of this disease.
Are we in America in danger of the plague? I will have to answer this question very much as I did two years ago: "Yes, we are in danger; but this danger, being foreseen, may be easily avoided." In my opinion, our most vulnerable point is along the Pacific coast. With the plague at Hong Kong, it is possible that it may be transferred to Manila, and the transports bringing soldiers to this country may also bring the infection. However, I think the chances of this happening are small. The length of time required to make the voyage from Manila to San Francisco is so great that, with the infection on board, it would be almost certain to manifest itself before reaching our shores, and, knowing its presence on board a ship reaching San Francisco or any other point on the western coast, thorough inspection and disinfection will keep the disease out of this country. The probabilities are that for several years to come the larger cities of India, at least, will remain infected, and our sanitary authorities must be vigilant. The fact that, if the plague reaches us at all, it must come by sea, that a long voyage must be made before it can reach us, and that the disease will most probably appear on board ship before arrival at any American port—all these conditions are in our favor. The General Government should take upon itself the control of all measures to prevent the introduction of infectious diseases from without. Quarantine detention is a relic of ignorance of the true nature of infectious diseases. All transports and other vessels between Manila and this country should be provided with proper disinfecting apparatus. The Government should supply the ​Marine-Hospital Service with every needed equipment, and if this be done the plague can enter America only through incompetency in that service. There is another source of danger on our Western coast that must not be overlooked. The plague is now widely distributed in Formosa, which is under the control of Japan, and our intercourse with the last-mentioned country should be most carefully watched.