It is commonly thought that Charles Darwin's great ideas in _On the Origin of Species_ originated with his cruise on the _Beagle_, especially those finches in the Galapagos. The cruise and the finches are of course important, but many of Darwin's ideas had their roots closer to home. After all, as Michael Boulter writes in _Darwin's Garden: Down House and The Origin of Species_ (Constable), Darwin didn't do much with the finches "other than to pack them carefully and send them off to storage." The _Beagle_ voyage lasted five years, ending in 1836, but Darwin and his family moved into Down House near the village of Downe in Kent, and he was to remain there until his death in 1882. Boulter, a paleobiologist who works in London's Natural History Museum, shows that it is not at all surprising that the garden proved to be an inspiration for many of Darwin's ideas, as well as being a site of repose and reflection, not to mention a gentlemanly hobby. He also brings us up to date on some current researches in evolution, many mysteries that Darwin tried to solve but only his successors managed to do so, and many mysteries which remain. With both the bicentennial of Darwin's birth and the sesquicentennial of the _Origin_ coming in 2009, readers would do well to look at this intriguing view of the garden that inspired Darwin, and the resultant gardenful of ideas that are still being worked out.
For Darwin, the garden was the attraction of the property at Downe. Darwin wrote that when they took it over, "The garden had none of the shrubberies or walls that now give shelter; it was overlooked from the lane and was open, bleak and desolate." This would all change; Boulter writes, "It would soon become clear to all members of the household that much more was going on in the apparently quiet garden than in the normal gentleman's plot." There were gadgets that measured the growth of animals and plants. There were keeps for rabbits and for pigeons. Fine netting was used to cover some plants to keep insects off, so there was no cross-pollination; Darwin thus experimented with primroses and showed that "nature tells us in the most emphatic manner that she abhors self-fertilization." Darwin was a keen observer, and his studies of geology and climate helped him see what was going on in his little Kentish patch, as bees distributed pollen, as primroses, anemones, and cowslips grew together and adapted to make new varieties and hybrids, and even as the Asiatic cockroach muscled in to take over from the native species. The breadth of his studies is quite amazing. There were pigeons and rabbits. He made careful observations of how tendrils of climbing plants searched for supports and grasped them. He raised 50 varieties of gooseberry to study divergence. He would involve his children in his observations (besides making them the direct subjects of his study) in, for instance, games with worker bees, trying to trace the pattern of the bees' flights. They tested the hearing of earthworms by simultaneously playing piano and bassoon and whistling at them, and getting no response. He turned to earthworms as the subject for the last of his books, but he had watched them for decades. He built a "wormstone", a stone that sank into the ground as the earth was displaced by burrowing earthworms, and he monitored patches of earth to see the speed at which the earthworms turned over the soil.
There were experiments that went wrong and investigations that led to dead ends. For instance, not knowing about Mendel's work, Darwin labored hard to find the "gemmules", the agents that were somehow collected from the cells of the body and concentrated in the sexual organs for transmission to the next generation. Darwin would have been amazed by the genetic maps that have now shown how species have split off from each other, or by the universality of the hox genes that in worms or humans turn off or on to give all of us our segmentations. Boulter covers these modern topics as outgrowths of Darwin's original garden investigations. There was a huge amount of activity in that garden, and the charm of Boulter's book is that it describes how Darwin with delight and patience investigated his broad range of interests within his small domain, eventually producing the grand idea that encompasses all biology.