Born in Africa_ The Quest for the Origins of Human Life - Martin Meredith [25]
‘Our water hole near the camp was little more than a liquid, muddy swamp, in which a rhino wallowed daily and, after wallowing, added a certain amount of urine’, wrote Leakey. ‘Not unnaturally, the water tasted very unpleasant and was not really fit to drink, but it was all we had’. Leakey’s attempts to devise a filter system of charcoal and sand made little difference. ‘Our soup, tea or coffee all tasted of rhino urine’, Mary recalled, ‘which we never quite got used to’. For all the hardships, however, she thrived on the adventure. When the expedition was over, she left for England knowing, she wrote, that she would never be the same again now that Africa had ‘cast its spell’ on her.
Returning to Kenya as a married couple in 1937, the Leakeys endeavoured to keep up their work on archaeological sites. Accepted as a professional archaeologist in her own right, Mary started excavations at a neolithic burial site at Hyrax Hill, a rocky ridge overlooking Lake Nakuru. Her work at Hyrax Hill was subsequently to gain high praise. She pioneered a technique of leaving stones and bones in exactly the same position in which they had been found, enabling other archaeologists to study their geological context, an innovation that set a new standard for excavation.
During the Christmas holiday in 1937, the Leakeys began digging at a burial site at Njoro on a farm belonging to Nellie Grant, mother of the writer Elspeth Huxley. But they were always short of funds, as Nellie Grant remarked in a letter:
The poor Leakeys are held up for wages money and only have two months’ work in sight on the skeletons, and need two years. They live on the smell of an oil-rag themselves, work all day on the site and up to eight or nine o’clock at night, sorting and labelling the day’s finds.
While the Leakeys were struggling to survive in Kenya, a new revolution in scientific thinking about evolution was gathering momentum in the West. For several decades, the field of evolutionary studies had been convulsed by competing theories. Some biologists held fast to the concept of orthogenesis, the idea that evolution was directed by an inner drive towards a fixed goal; some favoured transmutationism, the theory that evolutionary change occurred through sudden mutations, or saltations, producing new species instantaneously; others subscribed to the idea of some sort of inheritance of acquired characteristics. Darwin’s theory of natural selection had long since fallen out of favour.
The new science of genetics added to the mix. Since 1900, geneticists had made great strides in working out the basic principles of inheritance, first enunciated by the Austrian monk Gregor Mendel in an obscure publication in 1865 but left unnoticed for thirty-five years. Mendel had discovered that physical traits were determined by stable inheritance factors, subsequently known as genes. By breeding strains of pea plants in his monastery garden, he found he could produce simple and mathematically predictable inheritance patterns. Inheritance, he showed, did not blend the genes of both parents; they remained discrete, so that rare genes from one parent could seem to vanish for a generation but reappear fully functional in the next generation. In the 1900s, a Dutch botanist, Hugo de Vries, added the theory that genes were capable of spontaneous changes, or ‘mutations’ that opened the way for further genetic