On Reading Diamond’s The Third Chimpanzee

Posted by jns on February 3, 2008

Recently I finished reading Jared Diamond’s The Third Chimpanzee : The Evolution and Future of the Human Animal (New York : HarperCollins Publishers, 1992, 407 pages). I quite enjoyed it. It’s the third of his books I’ve read. I previously enjoyed Collapse and Guns, Germs, and Steel, but I didn’t mind that this was a significantly shorter book. Here’s my book note.

In some ways this book rehearses arguments that will appear in the later, larger tomes in much more fleshed-out form, but it’s still its own book. This one’s theme is, more or less, an evolutionary look at what makes humans human. As usual, I found a few excerpts I wanted to share that didn’t quite fit into the note.

In a discussion of sexual selection, the subject of the human penis arises (if you’ll pardon the expression), and the glib answer would say something about the size of the penis’ being selected as a display, implying that the display is directed towards females. But, perhaps not….

While we can agree that the human penis is an organ of display, the display is intended not for women but for fellow men.

Other facts confirm the role of a large penis as a threat or status display toward other men. Recall all the phallic art created by men for men, and the widespread obsession of men with their penis size. Evolution of the human penis was effectively limited by the length of the female vagina: a man’s penis would damage a woman if it were significantly larger. Howerver, I can guess what the penis would look like if this practical constraint were removed and if men could design themselves. It would resemble the penis sheaths (phallocarps) used as male attire in some areas of New Guinea where I do fieldwork. Phallocarps vary in length (up to two feet), diameter (up to 4 inches), shape (curved or straight), angle made with the wearer’s body, color (yellow or red), and decoration (e.g., a tuft of fur at the end). Each man has a wardrobe of several sizes and shapes from which to choose each day, depending on his mood that morning. Embarrassed male anthropologists interpret the phallocarp as something used for modesty or concealment, to which my wife had a succinct answer on seeing a phallocarp: “The most immodest display of modesty I’ve ever seen!” [p. 76]

The discussion moves on to the curious case of concealed ovulation in humans, at least compared to our animal relatives.

So well concealed is human ovulation that we did not have accurate scientific information on its timing until around 1930. Before that, many physicians thought that women could conceive at any point in their cycle, or even that conception was most likely at the time of menstruation. In contrast to the male monkey, who has only to scan his surroundings for brightly swollen lady monkeys, the unfortunate human male has not the faintest idea which ladies around him are ovulating and capable of being fertilized. A woman herself may learn to recognize sensations associated with ovulation, but it is often tricky, even with the help of thermometers and ratings of vaginal mucus quality. Furthermore, today’s would-be mother, who tries in such ways to sense ovulation in order to achieve (or avoid) fertilization, is responding by cold-blooded calculation to hard-won, modern book knowledge. She has no other choice; she lacks the innate, hot-blooded sense of sexual receptivity that drives other female mammals.

Our concealed ovulation, constant receptivity, and brief fertile period in each menstrual cycle ensure that most copulations by humans are at the wrong time for conception. To make things worse, menstrual-cycle length varies more between women, or from cycle to cycle in a given woman, than for other female mammals. As a result, even young newlyweds who omit contraception and make love at maximum frequency have only a 28 percent probability of conception per menstrual cycle. Animal breeders would be in despair if a prize cow had such low fertility, but in fact they can schedule a single artificial insemination so that the cow has a 75 percent chance of being fertilized! [pp. 77--78]

Diamond has spent much of his research career among the people of New Guinea. He talks at length of “first contact”, the strange moment when two tribes of people discover each other, previously knowing nothing of their existence. Remarkable, before 1938, it was thought that the interior of New Guinea was unpopulated. The Archbold Expedition of 1938 unexpectedly found that the Grand Valley was populated by some 50,000 people. (There’s another excerpt about the Archbold Expedition in the book note.) What a shocker! But contact has its price. I found this story particularly poignant.

Take artistic diversity as one obvious example. Styles of sculpture, music, and dance used to vary greatly from village to village within New Guinea. Some villagers along the Sepik River and in the Asmat swamps produced carvings that are now world-famous because of their quality. But New Guinea villagers have been increasingly coerced or reduced into abandoning their artistic traditions. When I visited an isolated tribelet of 578 people at Bomai in 1965, the missionary controlling the only store had just manipulated the people into burning all their art. Centuries of unique cultural development (“heathen artifacts,” as the missionary put it) had thus been destroyed in one morning. [p. 231]

On Reading Napoleon’s Buttons

Posted by jns on February 1, 2008

Also a few months back, I read the delightful Napoleon’s Buttons : How 17 Molecules Changed History, by Penny Le Couteur and Jay Burreson (New York : Jeremy P. Tarcher/Putnam, 2003, 375 pages). I haven’t run across so many popular chemistry books so far, but this clearly is one of the good ones. I enjoyed the blend of historic anecdote, chemical analysis, introduction of technical vocabulary, and copious molecular diagrams. Yes! A popular-science book with molecular diagrams! At whatever level one reads the diagrams–even if one sees them only as decoration–they enhanced the text in my opinion.

My book note is here. Below is an extra extract on a subject that I find fascinating and unlikely: the discovery of saponification, that magical transformation of fat and ashes that creates some that cleans things! So, here we have some social history of bathing, chemical history of saponification and relsted topics, and some fun facts thrown in to blend the flavors.

(As an aside, this excerpt ends just at the idea of long molecules called “lipids” is introduced. It’s the physical chemistry of lipids that allows soap to wash away grease in water. How that all works and some of the collective properties of lipids doing their job was a hot topic among my fellow condensed-matter physicists in my early research days, although I never worked on it myself.)

In Europe the practice of bathing declined along with the roman Empire, although public baths still existed and were used in many towns until late in the Middle Ages. During the plague years, starting in the fourteenth century, city authorities began closing public baths, fearing that they contributed to the spread of the Black Death. By the sixteenth century bathing had become not only unfashionable but was even considered dangerous or sinful. Those who could afford it covered body odors with liberal applications of scents and perfumes. Few homes had baths. A once-a-year bath was the norm; the stench of unwashed bodies must have been dreadful. Soap, however, was still in demand during these centuries. The rich had their clothes and linens laundered. Soap was used to clean pots and pans, dishes and cutlery, floors and counters. Hands and possibly faces were washed with soap. It was washing the whole body that was frowned upon, particularly naked bathing.

Commercial soap making began in England in the fourteenth century. As in most northern European countries, soap was made mainly from cattle fat or tallow, whose fatty acid content is approximately 48 percent oleic acid. Human fat has about 46 percent oleic acid; these two fats contain some of the highest percentages of oleic acid in the animal world. by comparison, the fatty acids in butter are about 27 percent oleic acid and in whale blubber about 35 percent. In 1628, when Charles I ascended to the throne of England, soap making was an important industry. Desperate for a source of revenue–Parliament refused to approve his proposals for increased taxation–Charles sold monopoly rights to the production of soap. Other soap makers, incensed at the loss of their livelihood, threw their support behind Parliament. Thus it has been said that soap was one of the causes of the the English Civil War of 1642-1652, the execution of Charles I, and the establishment of the only republic in English history. This claim seems somewhat far-fetched, as the support of soap makers can hardly have been a crucial factor; disagreements on policies of taxation, religion, and foreign policy, the major issues between the king and Parliament, are more likely causes. In any event, the overthrow of the king was of little advantage to soap makers, since the Puritan regime that followed considered toiletries frivolous, and the Puritan leader, Oliver Cromwell, Lord Protector of England, imposed heavy taxes on soap.

Soap can, however, be considered responsible for the reduction in infant mortality in England that became evident in the later part of the nineteenth century. From the start of the Industrial Revolution in the late eighteenth century, people flocked to towns seeking work in factories. Slum housing conditions followed this rapid growth of the urban population. In rural communities, soap making was mainly a domestic craft; scraps of tallow and other fats saved from the butchering of farm animals cooked up with last night’s ashes would produce a coarse but affordable soap. City dwellers had no comparable source of fat. Beef tallow had to be purchased and was too valuable a food to be used to make soap. Wood ashes were also less obtainable. Coal was the fuel of the urban poor, and the small amounts of coal ash available were not a good source of the alkali needed to saponify fat. Even if the ingredients were on hand, the living quarters of many factory workers had, at best, only rudimentary kitchen facilities and little space or equipment for soap making. Thus soap was no longer made at home. It had to be purchased and was generally beyond the means of factory workers. Standards of hygiene, not hight to state with, fell even lower, and filthy living conditions contributed to a high infant death rate.

At the end of the eighteenth century, though, a French chemist, Nicolas Leblanc, discovered an efficient method of making soda ash from common salt. The reduced cost of this alkali, an increased availability of fat, and finally in 1853 the removal of all taxes on soap lowered the price so that widespread use was possible. The decline in infant mortality dating from about this time has been attributed to the simple but effective cleansing power of soap and water.

Soap molecules clean because one end of the molecule has a charge and dissolves in water, whereas the other end is not soluble in water but does dissolve in substances such as grease, oil, and fat. [pp. 286--288]