Plagues and Peoples (34 page)

Such a general change in macroparasitic patterns had not occurred in human history since the end of the second millennium
B.C
., when the dawn of the Iron Age made weapons (and tools) vastly cheaper than before, and thereby increased the devastation men could wreak upon their fellows. Some twenty-five hundred years later the invention of cannon made weaponry more expensive. The new technology therefore acted in the opposite way, directing organized violence into narrower channels so that fewer human beings died in war or from its consequences despite the enhanced killing power well-equipped armies could exert in battle and siege.

Taxes to support the new armament were heavy. Collection probably became more regular in parts of Asia and Europe, as bureaucratic structures of government consolidated their hold on supreme armed force thanks to the new power cannon could exert. But for peasants and artisans, regular taxation, even if hard to bear, was almost always less destructive than raiding and rapine of the sort that armed bands had resorted to for their support ever since barbarians carrying iron swords and shields had assaulted the citadels of Middle Eastern civilization after 1200
B.C
. The symbiosis of cannon with a limited number of imperial bureaucracies must therefore be counted as a third global factor favoring the world-wide growth of
civilized populations from the late seventeenth century until the present day.

These three factors continue to affect the conditions of human life in the twentieth century. Indeed the world’s biosphere may be described as still reverberating to the series of shocks inaugurated by the new permeability of ocean barriers that resulted from the manifold movement of ships across the high seas after 1492. Yet almost as soon as the initial and most drastic readjustments of the new pattern of transoceanic movements had subsided, other factors—scientific and technological for the most part—inaugurated still further and almost equally drastic changes in the world’s biological and human balance. To survey them will be the task of our next chapter.

VI

The Ecological Impact of Medical Science and Organization Since 1700

H

itherto in seeking to understand the changing patterns of disease and its importance for human history as a whole, there has been little occasion to mention the practice of medicine. Undoubtedly folkways that reduced exposure to disease were as old as human society and language; and various customs, justified on other grounds, also had important epidemiological consequences—often of a positive kind. Thus, as we saw in
Chapter IV
, nomads of Manchuria diminished their exposure to plague on the basis of a theory that departed ancestors might be reincarnated as marmots. As such, these animals, which sometimes harbored the plague bacillus, had to be treated with special care.
¹
Another modern folk practice helped to protect the health of Tamil laborers brought from southern India to work on plantations in Malaya. They conformed to a custom that required them to bring water into their houses only once a day, and not to store it between times. This, of course, deprived mosquitoes of a breeding place indoors. As a result, Chinese as well as native Malays, who lived and worked under similar conditions but
did not observe the Tamil custom, suffered distinctly higher rates of infection from dengue fever and malaria.
²

In numberless circumstances, such beliefs and rules of behavior must have helped to insulate human communities from disease chains. On the other hand, hygienic rules, especially when promulgated on the authority of divine revelation presumed to be universally applicable, sometimes had unfortunate side effects, as in the instance of the mosque in Yemen whose ablution pool harbored bilharzia parasites.
³

More generally, religious pilgrimages rivaled warfare in provoking epidemic infection. The doctrine that disease came from God could easily be interpreted to mean that it was impious to interfere with God’s purposes by trying to take conscious precaution against disease, either in war or on pilgrimage. Part of the meaning of pilgrimage was the taking of risks in pursuit of holiness. To die en route was, for the pious, an act of God whereby He deliberately translated the pilgrim from the hardships of life on earth into His presence. Disease and pilgrimage were thus psychologically as well as epidemiologically complementary. The same may be said of war, where risk of sudden death—one’s own or the enemy’s—was at the very core of the enterprise.

Thus customs and beliefs tending to safeguard human communities from disease were matched by others that invited and provoked disease outbreaks. Until very recently, medical theories and treatments fitted into this tangle of contradictory practices smoothly enough. Some cures were helpful; some indifferent; some, like the practice of bleeding for fevers, must have been positively harmful to most patients. Like popular folkways, medical theories were crudely empirical and excessively dogmatic. Doctrines set forth in a few famous books were treated as authoritative: Galen and Avicenna for the European and Moslem world played this role, as Caraka did for the Indian; whereas in China, several authors shared canonical status. Experience was then interpreted in terms of theory, and cures inflicted accordingly.

Overall, it is very doubtful whether the physiological benefits
of even the most expert medical attention outweighed the harm done by some of the common forms of treatment. The practical basis of the medical profession rested on psychology. Everyone felt better when self-confident, expensive experts could be called in to handle a vital emergency. Doctors relieved others of the responsibility for deciding what to do. As such their role was strictly comparable to that of the priesthood, whose ministrations to the soul relieved anxieties parallel to those relieved by medical ministrations to the body.

Yet there was a difference. Doctors dealt with things of this world- and as such their skills and ideas were more liable to empiric elaboration over time. Medical professionals in fact behaved in about the same way as humble folk did by cherishing responses to disease that by some happy chance seemed to achieve desired results. This relative openness to new departures was, perhaps, the most important quality of the medical professional prior to the spectacular breakthroughs of the past century or so. Even the august Galen was subject to emendation, though it was not before the seventeenth century that the theory of humors on which he had based his medical practice began to be widely questioned among European doctors. Among Asians, medical ideas and practices, once they achieved a classical definition, seem to have responded less coherently to novelty.
⁴

The organization of the profession in Europe around medical schools and hospitals may have been decisive in producing more systematic responses to new disease experiences. Hospitals gave opportunity for repeated observation of the symptoms and course of a disease. A cure that worked once could be tried again on the next patient, and professional colleagues were on hand to observe the result. Such colleagues stood ready to accord admiration and respect to the man whose cures worked better than usual; and a reputation for skill above the ordinary also meant swiftly rising income for the successful innovator. Under such circumstances, everything pushed the ambitious medical man toward empiric adventure, trying out new cures and watching to see the result. Moreover,
the ancient Hippocratic tradition, emphasizing careful observation of disease symptoms, made such conduct professionally respectable. It is not, therefore, surprising that European doctors reacted to the disease novelties of 1200–1700 by altering major elements of older theory and practice. By contrast, Asian medical experts, who did not operate in hospital environments, met the disease experiences of these centuries by holding fast to ancient authorities—or claiming to do so even when something new crept in.

To be sure, even in Europe almost a century passed before medical response to the emergency of plague achieved anything resembling a clear definition. But by the end of the fifteenth century, Italian doctors had worked out within the framework of city-state government a series of public health measures designed to quarantine plague, and if it came, to cope with the heavy die-offs such visitations regularly brought. In the course of the sixteenth century these measures became both more elaborate and better administered. Preventive quarantines probably began to intercept chains of plague infection more and more often. Theories of contagion were advanced to justify quarantine, and notions originating from practical folk experience such as the belief that wool and textiles could carry plague—a belief vindicated by the behavior of hungry fleas that, having taken refuge in a bale of wool after their rat host had died, were liable to discover a much-wanted next meal by biting the arm of the man who unpacked the bale—at least achieved the dignity of being discussed in print.
⁵

European doctors reacted to the disease consequences of the discovery of America in much the same way as their predecessors had to the plague. Learned discussion of syphilis was as florid as the symptoms of the disease itself when new. Other novelties excited no less attention, and none of them fitted smoothly with ancient learning. The blow to reverence for the ancients was fundamental, and one from which traditional medical practice and education could never completely recover. As more and more details about America became avail-
able, the inference that modern knowledge had, in some ways at least, surpassed the ancients became irresistible. Such views opened wider the door to medical innovation, and encouraged Paracelsus (1493–1541) to reject Galen’s authority entirely. New diseases like syphilis seemed to call for new and “stronger” medicines; and this became one of the stock arguments for resort to the Paracelsian chemical pharmacopeia and mystical medical philosophy.
⁶
With every fundamental of medicine thus called into question, the only logical recourse was to observe results of cures administered in accordance with the old Galenic as against the new Paracelsian theories, and then to choose whichever worked better. The swift development of European medical practice to levels of skill exceeding all other civilized traditions resulted.

Nevertheless, before the eighteenth century the demographic impact of the profession of medicine remained negligible. Relatively few persons could afford to pay a doctor for his often very expensive services; and for every case in which the doctor’s attendance really made a difference between life and death, there were other instances in which even the best available professional services made little difference to the course of the disease, or actually hindered recovery. For this reason, mention of medical practice and its history in the earlier chapters of this book seemed unnecessary. Only with the eighteenth century did the situation begin to change; and it was not really until after 1850 or so that the practice of medicine and the organization of medical services began to make large-scale differences in human survival rates and population growth.

Long before then, the new ecological balances among the world’s continents and civilizations that had begun to define themselves in the latter half of the seventeenth century became spectacularly evident. In particular, massive population growth in China and Europe assumed unexampled scale, thanks to the fact that both regions started from a higher initial population level than similar growth spurts of times past had ever done. After about 1650 Amerindian population figures
began to bottom out in those regions where exposure to European and African diseases was of longest standing, and by the mid-eighteenth century Old World emigrants to America began to demonstrate remarkable rates of natural increase. Die-offs among formerly islanded populations continued (e.g., among natives of Oceania); but this phenomenon affected smaller numbers, since after the sixteenth century no really large human communities remained outside the disease-net European shipping had already woven across all the earth’s oceans and coastlines.
⁷

To be sure, even in the most intensely studied regions, population estimates for the seventeenth century are unsatisfactory, so that statistical demographers now prefer to begin making generalizations about 1750, rather than, as an earlier generation of experts had tried to do, retrojecting their estimates to 1650.
⁸
But no one doubts that sometime between 1650 and 1750 (and recent opinion inclines toward the latter rather than the earlier date), a “vital revolution” took place in parts (though not in all) of Europe, manifesting itself in a more massive population growth than that continent had ever known before. The same was true in China, where the pacification brought by the new Manchu Dynasty after 1683 inaugurated a century of population growth during which Chinese numbers more than doubled, rising from about 150 million in 1700 to about 313 million in 1794.
⁹

By comparison, Europe’s population seems puny, reaching only a total of about 152 million by 1800.
¹⁰
Moreover, the unparalleled spurt in Chinese population affected all parts of the country, whereas in Europe comparable growth rates were chiefly evident toward the margins—in the steppelands to the east and in Great Britain and America to the west. The core area of continental Europe continued to suffer periodic devastation by war and crop failure, so that any tendency toward massive population growth of the sort manifest in China was quite effectually masked until late in the eighteenth century.

The relation between population growth and the intensification of industrial production which we have learned to call
the Industrial Revolution, is a much debated point among historians, and especially among historians of England.
¹¹
That country witnessed extraordinary changes in both industry and population during the eighteenth century; and the two obviously supported each other, in the sense that new industry needed workers, and expanding population needed new means of livelihood. Minute study of English parish records has much to teach in these matters; but to understand the general process one must consider all of Europe and the transoceanic zones of colonization as an interacting whole. Such a perspective on European demography, 1650–1750, brackets the agricultural pioneering and population growth along the eastern frontier with the parallel process of pioneering taking place in colonial lands across the seas, above all in North America. The difference between migration overland and migration overseas was less significant than the basic identity of the process of opening up new agricultural land that was taking place simultaneously on both frontiers. The intensification of commercial industrial activity in the center, mainly in Great Britain, also requires this larger perspective, for it was as a focus of the enlarged Europe of the Old World and the New that the English Midlands and London developed the new commercial and industrial patterns—above all more extensive use of mechanically powered machinery—that we lump together as the industrial revolution. But even if one accepts this expanded definition and counts both wings of the colonial movement as part of Europe, it only adds about 8–10 million to the total for European populations in 1800.
¹²
Hence the increase of European numbers remains far less massive than the Chinese expansion of the same period, being only about one fifth as great.