Surat. The next outbreak in India fell to be described by three British writers. It happened in Cutch and Kathiawar from 1815 to 1821, in peculiar circumstances of aggravation within walled. towns, arising out of famine and the mode of collecting the tribute from the recalcitrant petty chieftains of those territories by the army of the Gaekwar, and it came to an end almost coincidently with the new order of things in 1821. The only other epidemic before the present was also a limited one, in Marwar, especially in the town of Pali, which lasted from 1836 to 1839, and may have been a revival of plague which is said to have been indigenous in Marwar "from a remote period."

Turning from those Indian precedents to the much more continuous and extensive plagues of Europe, we find an uninterrupted history in one country or another and in one city or another for more than three hundred years-from the year 1347 to the latter half of the seventeenth century, when the infection disappeared almost simultaneously from all the countries of western Europe. The chief difference between the European plague period and the one which is now running its course in India is that the former did not involve the villages, but only the towns, except in its first great wave, from 1347 to 1350, which swamped country and town alike with an almost unheard-of mortality, and excepting, perhaps, two or three general but minor revivals at intervals in the latter half of the fourteenth century; for the rest, it continued an infection of the towns, and in these it commonly broke out at long intervals-twenty or forty years-excepting in such capitals as London, where it was seldom dormant for a series of years until it was about to cease altogether.

It is not surprising that plague in India should be chiefly an affair of the villages, because that has been also the experience with cholera. So much was that a village infection that Anglo-Indian writers who were at home when cholera reached this country in 1831 prophesied that it would fall most upon the enormously congested rural population of Ireland. But it spared the Irish villages and hamlets almost absolutely, although it attacked the Irish cities severely. European precedents being thus inapplicable to India as to villages, we are thrown back upon the lessons that may be learned from the history of plague in India itself during the last nine years. It is only from the Bombay Presidency that we have data minute enough to be of much use, from which it appears that the huge totals of plague deaths year after year are not so hopeless as they look. When they are analyzed-and it is no small labor to analyze them-it is found that the aggregate of each year has been made up by items from somewhat different places. The cities of Bombay, Poona, and Karachi have been steady, but in the mofussil all the districts have

not suffered severely in the same year, the tálukas within a given district have been affected some one year, some another, and the villages of a given táluka have been affected in a kind of rotation. I have shown on the screen the tables of nine villages, which on the whole agree in proving that each village has had one very severe outbreak, usually the first, that there have been years absolutely clear, and that the subsequent outbreaks have been much less extensive than the original one. It is in the very notion or definition of the word “epidemic" that there shall be intermissions; the word "endemic" means a more steady prevalence from year to year-but in that notion also the steadiness is only in the aggregate of a whole country or province, not in the several counties or parishes of it. It is probable that all the villages of Bombay Presidency by this time have had their worst experience of plague, and that in each village plague has visited all the houses in turn, or as many of them as it is ever likely to visit. The Bombay figures for the season just ended are encouraging. Whether it be owing to the resolute practice of evacuation on the first signs of plague or because the invasion is subsiding naturally, the returns since January have been only about one-third those of the three or four years preceding for the corresponding weeks. It looks as if the maximum had been reached and passed, both for each locality and in the aggregate of the whole Presidency, and that there is to be a pause. Such pauses occur in all epidemic infections. We account for them by a phrase or formula that the infection has exhausted all the "susceptible subjects," and we explain the return of the epidemic after an interval of years by the fact that a new generation has grown up which contains more "susceptible subjects."

What can be proved from the admirably full statistics of the Bombay Presidency may be perceived in a way in the Punjab. Thus, in Jullundur, in January this year, I learned that the average was being kept up to that of former years chiefly by returns from a certain group of villages in the southwest which were having plague in them. for the first time. The province as a whole is to have more plague deaths this year than it has had hitherto; but it would certainly have shown a decrease but for the very large items of three districts. in the Delhi division-Gurgaon, Rohtak, and Hissar-which are having their first severe epidemic. The prognosis for the Punjab should be that the infection has reached its height and done its worst for the time in the districts first attacked and that it will soon begin to show a decline in the aggregate, following in the wake of Bombay Presidency.

This is the first year in which the United Provinces and Behar have returned such large totals as we have been accustomed to for several

years in Bombay and the Punjab, and as one of them has a population nearly twice as great as these two latter together, it is unsafe to prophesy what heights plague may not reach in them before it begins to decline. In any case we may reckon with plague domesticated in the soil of tens of thousands of villages, making an endemic area larger than that of cholera was ever estimated to be, and from such an endemic area we may expect future outbreaks at intervals of years, if not from year to year. In England, for thirty or forty years after the great invasion of plague in 1348, a poet of the time compared the state of sickness to "the rain that raineth where we rest should" to the drip through a leaky roof, a chronic state of discomfort and uneasiness.

The three centuries of plague in European towns came to an end without any conscious effort to check the infection anywhere, so far as one knows. The most probable explanation is that the towns had emerged slowly from their mediæval life, which was peculiarly favorable to plague, having thrown down their walls and gates and gradually shifted the pressure of population to new sites, which, however, were often befouled by the accumulated refuse of the old walled city, and therefore apt to retain the infection many years longer. The curious statutes of 32 and 35, Henry VIII, on the decay of practically all the chief towns of England and Wales, bear out that hypothesis, according to the reading of their preamble adopted by Nicholls and Froude. At all events medieval limits were outgrown in all the towns of Europe, and, after a transition period of a century or more, plague died out by reason of changed conditions.

India at the present day contains more traces of changed sites than any country in the world, and some of these changes have actually occurred under British rule. Sometimes the changes of site have been caused by a river deserting its old channel and leaving a city too far from the traffic, but there are undoubted instances of sites abandoned owing to chronic sickness. The British cantonments afford instances in the past and may afford more in the future. Dacca and Berhampore were both condemned, the latter in 1833 after an original outlay of £300,000; they were healthy stations at first and became sickly by degrees until they were untenable. What has been happening in India from time immemorial, both to town sites and to village sites through the pressure of events, may be anticipated by a deliberate policy in order to hasten the disappearance of plague. In some of the towns of the Deccan and Gujarat new suburbs are actually springing up for the richer class to avoid the infection. For the villages it is not out of the question that some law might be made to prevent rebuilding on the same foundation when the mud walls crumble, as they do periodically; but of such a law the essential condition would be the

helping hand of the State to provide new sites. At one time I held that a progressive change of the village site to a clean soil, along with the break-up of a larger village into several hamlets, would be an effectual if very slow means of getting rid of plague. But after seeing a good many of those dreadful mud villages I have come to think that it is their miserable structure that is the real reason why the Indian plains are cursed with plague, and that there can be no real cure without a more civilized kind of dwelling and a great revival of the native building arts as village industries.

THE FIGHT AGAINST YELLOW FEVER."

By A. DASTRE.

Once again yellow fever claims our attention. While we are celebrating the victorious effort of science in driving that dread disease from its hereditary domains in Habana and Rio Janeiro, it reappears and desolates New Orleans; it revives in Honduras and threatens Panama. Once more we must fight to renew the achievements of the Americans in Cuba and of the Brazilians in Rio. And that is possible, for we can struggle to-day with hope, with certainty of success. For centuries the disease remained unconquerable. Physicians knew only what everybody sees-the external signs-the symptoms and fatal results, but they were not familiar with the true nature of the disease and the manner of its propagation.

In fact, even to-day our knowledge of the nature of the evil is very elementary; we have few facts concerning the micro-organism of yellow fever. The only proven point is that it is a blood parasite, not feeding upon the red corpuscles like the parasite of malaria, but only upon the fluid part-the "plasma." It is believed that it does not affect the transparency of liquids, that it can penetrate most filters, and that it remains invisible to the microscope.

But if the deadly agent, the ultramicroscopic germ, which is the specific cause of the disease, is not well known, we are at least familiar with the means of its propagation, the sole agent of its transmission, and that is sufficient, as we shall see, rationally and effectually to eliminate contagion.

This definite agent, the only one capable of inoculating a man with the micro-organism of yellow fever, is a particular species of mosquito, the Stegomyia fasciata, known also as Culex calopus and previously called Culex fasciata. At the time of Linné, in 1758, only 6 species of mosquitoes were known. In 1902, 250 different species could be distinguished, and the number has since increased to nearly 400 described species. The English naturalist, F. V. Theobald, an authority on the subject, recognized 29 genera. To one of

a Translated from Revue des Deux Mondes, Paris, September 1, 1905.