Plagues and Peoples (16 page)

It is a moot point whether organized fighting and the disruptions of market relations resulting from war were more costly to Mediterranean populations than imperial bureaucratic consolidation under the Romans turned out to be. One cannot therefore confidently argue that macroparasitic drain upon food providers in the Mediterranean coastlands before 30
B.C
. was less than in contemporary China or the Middle East. Yet the prevalence of self-governing cities, in which a few thousand families managed their economic and political affairs as best they could, and as they themselves saw fit, certainly gave classical Mediterranean (and subsequent European) civilization a deep-seated preference for this sort of freedom. The price of such political fragmentation was frequent war, but this Europeans have long seemed willing to pay.

If we turn attention to the microparasitic side of the bal-
ance, it appears that Mediterranean coastlands offered a relatively disease-free environment into which populations could and did expand. The new patterns of cultivation did not of themselves invite new forms of microparasitism. Olive trees are believed to have been part of the wild flora of Greece before men did anything to alter it. Their cultivation, accordingly, involved relatively modest disruptions of pre-existing landscapes, particularly since olive trees will often flourish on rocky hillsides where little else will grow. Vines may have come
into
Greece
from
better-watered regions to the north. According to myth, Dionysos, the god of wine, hailed from Thrace, and this may preserve a memory of the importation of vines from that region. But even if they came from elsewhere, vines did not require alterations of pre-existing ecological balances nearly as drastic as those involved in rice paddy cultivation of the sort Chinese (and probably also Indian) farmers were experimenting with at the time vine cultivation reached Greece. The same may be said for the expansion of grain fields on the coastlands of the Black Sea and western Mediterranean. Wheat and barley were plants native to Near Eastern lands, and may also have belonged among the grasses of Mediterranean regions before men domesticated them. Thus, spread of grain farming also involved comparatively modest alterations of older biological balances.

There is, in short, no reason to think that the new cropping pattern brought with it any particular exposure to new diseases in Mediterranean coastlands. To be sure, as population became denser, various infections must have become commoner. The most important of these was surely malaria, although other and diverse parasites, often propagated via polluted water supplies, undoubtedly multiplied as people gathered into cities and became more numerous.

Hippocrates, the father of Greek medicine (traditional dates 460–377
B.C
.), recorded case histories with enough precision and detail to prove the existence of diverse infections in ancient Greece, though in most cases we cannot determine from his words exactly which disease as recognized today may have
been at work. He does unmistakably record an epidemic of mumps on the island of Thasos, and the three- and four-day fevers he refers to frequently must be ancestral to modern tertian and quartan malaria.
²²
With less certainty, modern medical experts may also identify diphtheria, tuberculosis and/or influenza from Hippocrates’ accounts of his patients’ symptoms, and the progress of their diseases.
²³
On the other hand, it is a striking and significant fact that no trace of smallpox or measles can be found in the Hippocratic writings. In view of the precision with which external symptoms were recorded, and the dramatic character of such diseases, it seems sure that Hippocrates and those of his followers responsible for creating the collection of writings that goes by Hippocrates’ name never encountered these diseases. The same applies to bubonic plague, the other great epidemic killer of later European history.

As compared to the ecological circumstances confronting Chinese and Indian peasantries, therefore, the peoples of the ancient Mediterranean (always excepting Egypt, that ancient focus of intense disease parasitism) seem to have had an easy time. Intensified exposure to malaria may, in some Mediterranean locales, have set definite limits upon agricultural expansion. But in the Roman campagna and some other parts of Italy that later became malarial wastelands, dense farming populations existed between the sixth and third centuries
B.C
. Elaborate underground channels were dug to drain natural swamps and secure water for irrigation and drinking. Enormous labor went into these engineering works, and the effect of such water management probably was to prevent the malignant forms of malaria from gaining a foothold in regions near Rome that later suffered radical depopulation because of the disease.
²⁴

As is now known, local details of environment that affect the relative abundance of one variety of mosquito as against others, have much to do with making one Mediterranean region malarial and another relatively free from the disease. Critical variables include the availability of suitable water for
hatching the eggs laid by different kinds of mosquitoes. Some species are adapted to spending their larval stage in moving as against still water, and in saline as against fresh. Presence and absence of minute trace elements in the water may also play a critical role in determining what sort of mosquito will prevail in a particular locality. In addition, such an unexpected item as the population ratio of human beings to cattle can make a difference. The mosquito species which is Europe’s most efficient vector of malaria, for example, prefers to feed on cattle. If enough alternate sources of blood are available to them, these mosquitoes will eschew potential human hosts and thus interrupt the chain of infection, since cattle do not suffer from malaria.
²⁵

Delicate and seemingly minor details of this kind suffice in modern times to define areas of malarial infestation in Mediterranean lands, and no one would claim that all relevant variables are yet recognized or fully understood. Under the circumstances no one can expect to decipher the critical variables in ancient environments that defined where and how seriously malaria interfered with human activity. One can make this general observation, nonetheless: about 700
B.C
., when the process of civilizational expansion throughout the Mediterranean coastlands began, the regions awaiting more intensive agricultural exploitation were either drier (as in North Africa) or cooler (as along the Black Sea coast and in parts of Italy and the western Mediterranean generally) than were the already developed Aegean and eastern Mediterranean (Syria, Palestine) regions. Both these circumstances tended to check intensification of disease even among increasingly dense human populations.

Malaria was undoubtedly destructive to humans in some places. Hippocrates’ description of chronic sufferers makes that clear: “Those who drink it [stagnant water, which he thought responsible for malarial symptoms] have always large, stiff spleens and hard, thin, hot stomachs, while their shoulders, collar bones and faces are emaciated; the fact is that their flesh dissolves to feed the spleen.…”
²⁶
Large cities, when
they took form, also undoubtedly became seats of intensified disease circulation, and human life was significantly shortened there as a result.
²⁷
But in spite of these facts, the Mediterranean landscape, as it evolved toward civilization, remained a relatively healthy place for human beings.

What little we know about ancient Greek, Roman, and Carthaginian social history suggests that up until the late third century
B.C
., when Rome and Carthage began to dispute imperial control of the western Mediterranean, the population of the classical world grew rather rapidly. Athens’ brief but brilliant imperial career between 480 and 404
B.C
. illustrates this unmistakably. Year after year, the Athenians sent out marauding fleets and armies; and sometimes their expeditions met with disaster. In 454
B.C
., for example, all the crews manning a fleet of ninety to one hundred ships were lost in Egypt; yet only four years later a new Athenian fleet of two hundred vessels set out to attack Cyprus. War losses did not, in fact, suffice to keep the Athenian population in check. In the days of their imperial strength, the Athenians seized lands from weaker peoples overseas in order to settle poor citizens abroad in colonies where they could live the life of a good citizen, i.e., as a respectable landowner and farmer. At least nine such settlements had come into existence by the outbreak of the Peloponnesian War in 431
B.C
., when Athenian imperial ambitions peaked and then collapsed in ruin.
²⁸

In later centuries, a similar growth in the size of the Macedonian and of the Italian peasant populations underlay the imperial expansion of Macedón and then of Rome, just as surely as Athenian population growth sustained that city’s period of greatness. The substantial emigration of Greeks to Asia, both before and after Alexander’s meteoric career, and the long series of Roman colonies planted throughout Italy in the course of that city’s expansion, attest to similarly rapid demographic growth. The same pattern presumably underlay Carthaginian imperialism, though subsequent defeat by Rome meant the loss of almost all records that might show details of Carthage’s population history.

To us, living also in an age of rapid population growth, this phenomenon may not seem particularly surprising nor need any special explanation. In the context of the entire human venture upon earth, however, persistent population expansion is exceptional. On a global time scale, in fact, population growth appears as a transient concomitant of some ecological upset permitting larger numbers of human beings to survive and multiply for a few generations until natural limits again assert themselves.

Among the most important factors in defining such natural limits are and always must be what I have called macro- and microparasitism. Changes in patterns of microparasitism affected Mediterranean populations profoundly, beginning in the second century
A.D
. This we will look into presently. But long before the ravages of new diseases began to cut into population, changes into macroparasitism incident to the rise of Roman imperial power had noticeably damaging effects. Wars and plunder worked vast and repeated destruction; enslavement and tax farming constituted almost as heavy a drain upon Mediterranean populations. After about 200
B.C
. we begin to hear of abandoned villages and empty countrysides. Peasant populations all but disappeared from some landscapes where previously they had sustained the pattern of demographic growth mentioned above. But until after
A.D
. 150 such regions (concentrated, characteristically, in the older centers of urban and imperial development like southern Greece and Italy) were counterbalanced by population expansion in other parts of the Mediterranean coastlands, e.g., in Spain and southern France, and in more distant regions along the Rhine and Danube that lay outside the Mediterranean climate zone as well.
²⁹

The over-all picture that emerges from these considerations is that during the first millennium
B.C
. in three important centers of human population, the balances between macro- and microparasitism adjusted themselves in such a fashion as to allow persistent population growth and territorial expansion
of civilized types of society. As a result, by the beginning of the Christian era, the civilizations of China, India, and the Mediterranean had attained a size and mass comparable to that of the more anciently civilized Middle East.

Definite population estimates are possible only for the Roman world and for Han China. Beloch’s guess of 54 million for the Roman empire at the time of Augustus’ death (
A.D
. 14) corresponds quite closely to the figure of 59.5 (or perhaps 57.6) million inhabitants of Han China, enumerated in an imperial census of
A.D
. 2.
³⁰
Both of these global figures probably err on the downward side, since in the nature of things no official record intended for tax and corvee purposes can catch everybody, but both are trustworthy indications of approximate magnitudes.
³¹

Populations attaining such massiveness, with appropriate concentrations in a few urban centers where tributes gathered from far and wide supported an imperial court, army, and administration, obviously could sustain our modern types of infectious childhood diseases. As we have seen, however, there is strong reason to believe that Mediterranean populations, at least, had not yet encountered such standbys as smallpox and measles in Hippocrates’ time.

How vulnerable such populations could be to a sudden irruption of unfamiliar infection is vividly illustrated by what happened in Athens in 430–429
B.C
. Thucydides’ famous and detailed clinical description of the disease that did so much to demoralize the Athenians and killed off about a quarter of the Athenian land army cannot be firmly identified with any modern infection.
³²
,
³³
,
³⁴
But if Thucydides is to be believed, the disease was new, and disappeared as mysteriously as it had come, afflicting only Athens and “the most populous of other towns.” The infection “first began, it is said, in the parts of Ethiopia above Egypt, and thence descended into Egypt and Libya and into most of the king’s country [i.e., Persia]. Suddenly falling upon Athens, it first attacked the population in Piraeus … and afterwards appeared in the upper city, when the deaths became much more frequent.”
³⁵
Since Piraeus was
the port of Athens and in frequent touch with the entire eastern shoreline of the Mediterranean, there can be little doubt that the disease came by sea and burnt itself out within a single season by creating so many antibodies in Athenian bloodstreams that the chain of infection could no longer be sustained.
³⁶