Guns, Germs, and Steel: Part III: Chapters 11-12

The husband was a small, timid man, sick with pneumonia caused by an unidentified microbe, and with only limited command of the English language.

The major killers of humanity throughout our recent history—smallpox, flu, tuberculosis, malaria, plague, measles, and cholera—are infectious diseases that evolved from diseases of animals, even though most of the microbes responsible for our own epidemic illnesses are paradoxically now almost confined to humans.

The dirtiest of all tricks for passive carriage is perpetrated by microbes that pass from a woman to her fetus and thereby infect babies already at birth.

The skin lesions caused by smallpox similarly spread microbes by direct or indirect body contact (occasionally very indirect, as when U.S. whites bent on wiping out “belligerent” Native Americans sent them gifts of blankets previously used by smallpox patients).

The specific antibodies that we gradually build up against a particular microbe infecting us make us less likely to get reinfected once we become cured.

That’s the principle of vaccination: to stimulate our antibody production without our having to go through the actual experience of the disease, by inoculating us with a dead or weakened strain of microbe.

Some have learned to trick us by changing those molecular pieces of the microbe (its so-called antigens) that our antibodies recognize.

As a result, over the course of history, human populations repeatedly exposed to a particular pathogen have come to consist of a higher proportion of individuals with those genes for resistance—just because unfortunate individuals without the genes were less likely to survive to pass their genes on to babies.

What’s true for measles in the Faeroes is true of our other familiar acute infectious diseases throughout the world. To sustain themselves, they need a human population that is sufficiently numerous, and sufficiently densely packed, that a numerous new crop of susceptible children is available for infection by the time the disease would otherwise be waning.

In fact, the first attested dates for many familiar infectious diseases are surprisingly recent: around 1600 B.C. for smallpox (as deduced from pockmarks on an Egyptian mummy), 400 B.C. for mumps, 200 B.C. for leprosy, A.D. 1840 for epidemic polio, and 1959 for AIDS.

Given our proximity to the animals we love, we must be getting constantly bombarded by their microbes.

Those invaders get winnowed by natural selection, and only a few of them succeed in establishing themselves as human diseases.

What is actually going on in those stages, as an exclusive disease of animals transforms itself into an exclusive disease of humans? One transformation involves a change of intermediate vector: when a microbe relying on some arthropod vector for transmission switches to a new host, the microbe may be forced to find a new arthropod as well.

The virus changed so as to kill fewer rabbits and to permit lethally infected ones to live longer before dying. As a result, a less lethal myxo virus spreads baby viruses to more rabbits than did the original, highly virulent myxo.

But when Cortes’s next onslaught came, the Aztecs were no longer naive and fought street by street with the utmost tenacity.

As we saw in Chapter 3, the result of the throne’s being left vacant was that two other sons of Huayna Capac, Atahuallpa and Huascar, became embroiled in a civil war that Pizarro exploited to conquer the divided Incas.

However, archaeological excavations, and scrutiny of descriptions left by the very first European explorers on our coasts, now suggest an initial number of around 20 million Indians.

In turn, we also saw that this extreme paucity of domestic animals in the New World reflects the paucity of wild starting material.

The three basic strategies underlying writing systems differ in the size of the speech unit denoted by one written sign: either a single basic sound, a whole syllable, or a whole word. Of these, the one employed today by most peoples is the alphabet, which ideally would provide a unique sign (termed a letter) for each basic sound of the language (a phoneme).

Before the spread of alphabetic writing, systems making much use of logograms were more common and included Egyptian hieroglyphs, Maya glyphs, and Sumerian cuneiform.

Like all alphabetic writing systems, English uses many logograms, such as numerals, $, %, and + : that is, arbitrary signs, not made up of phonetic elements, representing whole words.

Linguists term this decisive innovation, which also underlies puns today, the rebus principle.

Such transmission of inventions assumes a whole spectrum of forms. At the one end lies “blueprint copying,” when you copy or modify an available detailed blueprint. At the opposite end lies “idea diffusion,” when you receive little more than the basic idea and have to reinvent the details.

Or was it merely that the revelation of America’s A-bomb at Hiroshima at last convinced Stalin of the feasibility of building such a bomb, and that Russian scientists then reinvented the principles in an independent crash program, with little detailed guidance from the earlier American effort?

Like Saint Cyril’s invention, Ulfilas’s alphabet was a mishmash of letters borrowed from different sources: about 20 Greek letters, about five Roman letters, and two letters either taken from the runic alphabet or invented by Ulfilas himself.

Convenient starting points for our discussion are the limited capabilities, uses, and users of early writing systems. Early scripts were incomplete, ambiguous, or complex, or all three.

Knowledge of writing was confined to professional scribes in the employ of the king or temple. For instance, there is no hint that Linear B was used or understood by any Mycenaean Greek beyond small cadres of palace bureaucrats.

About 90 percent of the tablets in the earliest known Sumerian archives, from the city of Uruk, are clerical records of goods paid in, workers given rations, and agricultural products distributed.

The Iliad and Odyssey were composed and transmitted by non-literate bards for non-literate listeners, and not committed to writing until the development of the Greek alphabet hundreds of years later.

Early Egyptian hieroglyphs recorded religious and state propaganda and bureaucratic accounts.

Preserved Maya writing was similarly devoted to propaganda, births and accessions and victories of kings, and astronomical observations of priests.

The oldest preserved Chinese writing of the late Shang Dynasty consists of religious divination about dynastic affairs, incised into so-called oracle bones.

A sample Shang text: “The king, reading the meaning of the crack [in a bone cracked by heating], said: ‘If the child is born on a keng day, it will be extremely auspicious.’”

As the anthropologist Claude Levi-Strauss put it, ancient writing’s main function was “to facilitate the enslavement of other human beings.”

For instance, the first preserved example of Greek alphabetic writing, scratched onto an Athenian wine jug of about 740 B.C., is a line of poetry announcing a dancing contest: “Whoever of all dancers performs most nimbly will win this vase as a prize.”