Plagues and Peoples by William H. McNeill Page B
Authors: William H. McNeill
Tags: 20th Century, Non-Fiction, European History, Plague, Medieval History, Biological History, Social History, Cultural History, v.5, disease, Medical History
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expansion of Paleolithic hunting bands throughout the temperate and sub-Arctic zones of the earth constituted a period of unprecedented biological success for humankind. But by the time all available hunting grounds had been occupied, the most suitable game animals in older regions had been depleted and in some cases entirely destroyed by overkill.
Depletion of big-game food resources obviously created a crisis of survival for hunters at different times in different parts of the world. Such crisis coincided with radical changes of climate associated with the retreat (since about 20,000 B.C.) of the most recent ice cap. These two factors presented human hunting communities with a series of severe environmental challenges. Wherever older ways ceased to work, the response was intensification of the search for food and experimentation with new sorts of things to eat. Exploitation of the sea marges, for example, led to the development of boats and fishing; gathering of edible seeds led other groups to develop agriculture.
Paleolithic hunters and gatherers in a rough way presumably recapitulated the experience of the earliest humanoids in their tropical cradleland. That is, once the obvious possibilities of new ecological niches had been exploited, a kind of rough equilibrium set in, whereby checks of various kinds supervened to halt the growth of human populations. What these were varied from place to place, community to community,and time to time. Nonetheless, it seems probable that outside the tropical zones where humanity had itself evolved, disease organisms were not very important. Parasites that could spread from host to host by direct bodily contact, like lice, or the spirochete of yaws, could survive in temperate climates within small and migratory hunting communities. As long as the infection acted slowly and did not incapacitate the human host too severely or too suddenly, such parasitisms could and probably did travel with hunting communities from humanity’s tropical cradlelands throughout the earth. But the array of such infections and infestations was vastly diminished from what had thriven in the tropical luxuriance of humanity’s oldest habitat.
As a result, ancient hunters of the temperate zone were most probably healthy folk, despite what appear to be comparatively short life spans. 17 That they were healthy is also supported by what is known about the life of contemporary hunting peoples in Australia and the Americas. Except for formidable illnesses traceable to recent contacts with the outside world, these peoples, too, seem to have been quite free from infectious disease and from infestation by multicelled parasites. 18 Anything else would be very surprising, for there was not enough time for the slow work of biological evolution to devise organisms and patterns of transfer from host to host suitable for cool and dry conditions such as would be needed to maintain a tropical level of infection and infestation among the small and relatively isolated communities of hunters who penetrated the world’s temperate and sub-Arctic climates.
Before such adjustments could affect human life, new and fateful inventions again revolutionized humanity’s relationships with the environment. Food production permitted a vast and rapid increase in the number of people, and soon sustained the rise of cities and civilizations. Human populations, once concentrated into such large communities, offered potential disease organisms a rich and accessible food supply that was quite as unusual, in its way, as the big game of the African savanna had been for our remoter ancestors. Micro-organismsin their turn could expect good hunting under the new conditions created by the development of human villages, cities and civilizations. How they took advantage of the new possibilities offered by human aggregation into large communities will be the theme of the next chapter.
II
Breakthrough to History
T he numerous extinctions of
Depletion of big-game food resources obviously created a crisis of survival for hunters at different times in different parts of the world. Such crisis coincided with radical changes of climate associated with the retreat (since about 20,000 B.C.) of the most recent ice cap. These two factors presented human hunting communities with a series of severe environmental challenges. Wherever older ways ceased to work, the response was intensification of the search for food and experimentation with new sorts of things to eat. Exploitation of the sea marges, for example, led to the development of boats and fishing; gathering of edible seeds led other groups to develop agriculture.
Paleolithic hunters and gatherers in a rough way presumably recapitulated the experience of the earliest humanoids in their tropical cradleland. That is, once the obvious possibilities of new ecological niches had been exploited, a kind of rough equilibrium set in, whereby checks of various kinds supervened to halt the growth of human populations. What these were varied from place to place, community to community,and time to time. Nonetheless, it seems probable that outside the tropical zones where humanity had itself evolved, disease organisms were not very important. Parasites that could spread from host to host by direct bodily contact, like lice, or the spirochete of yaws, could survive in temperate climates within small and migratory hunting communities. As long as the infection acted slowly and did not incapacitate the human host too severely or too suddenly, such parasitisms could and probably did travel with hunting communities from humanity’s tropical cradlelands throughout the earth. But the array of such infections and infestations was vastly diminished from what had thriven in the tropical luxuriance of humanity’s oldest habitat.
As a result, ancient hunters of the temperate zone were most probably healthy folk, despite what appear to be comparatively short life spans. 17 That they were healthy is also supported by what is known about the life of contemporary hunting peoples in Australia and the Americas. Except for formidable illnesses traceable to recent contacts with the outside world, these peoples, too, seem to have been quite free from infectious disease and from infestation by multicelled parasites. 18 Anything else would be very surprising, for there was not enough time for the slow work of biological evolution to devise organisms and patterns of transfer from host to host suitable for cool and dry conditions such as would be needed to maintain a tropical level of infection and infestation among the small and relatively isolated communities of hunters who penetrated the world’s temperate and sub-Arctic climates.
Before such adjustments could affect human life, new and fateful inventions again revolutionized humanity’s relationships with the environment. Food production permitted a vast and rapid increase in the number of people, and soon sustained the rise of cities and civilizations. Human populations, once concentrated into such large communities, offered potential disease organisms a rich and accessible food supply that was quite as unusual, in its way, as the big game of the African savanna had been for our remoter ancestors. Micro-organismsin their turn could expect good hunting under the new conditions created by the development of human villages, cities and civilizations. How they took advantage of the new possibilities offered by human aggregation into large communities will be the theme of the next chapter.
II
Breakthrough to History
T he numerous extinctions of
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