For much of his adult life, Charles Darwin's health was repeatedly compromised by an uncommon combination of symptoms, leaving him severely debilitated for long periods of time. However, in some ways this may have helped his work, and Charles Darwin wrote "Even ill-health, though it has annihilated several years of my life, has saved me from the distractions of society and amusement." He consulted numerous doctors, but, with the medical science of the time, the cause remained undiagnosed. He tried all available treatments, but, at best, they had only temporary success. More recently, there has been much speculation as to the nature of his illness. Development of illness and symptoms As a medical student at the University of Edinburgh, Darwin found that he was too sensitive to the sight of blood and the brutality of surgery at the time, so he turned his attention to natural history, an extramural interest he developed when studying at the University of Cambridge to qualify as a clergyman. On 10 December 1831, as he waited in Plymouth for the voyage on HMS Beagle to begin, he suffered from chest pain and heart palpitations, but told no one at the time in case it stopped him from going on the survey expedition. During the voyage, he suffered badly from sea-sickness during the eighteen months he was at sea, but he spent much of the three years and three months he was on land in strenuous exploration. In Argentina at the start of October 1833, he collapsed with a fever. He spent two days in bed, and then memories of a young shipmate who had died of the fever persuaded him to take a boat down river to Buenos Aires, lying ill in his cabin until the fever passed. On 20 September 1834, while returning from a horseback expedition in the Andes mountains, he fell ill and spent the month of October in bed in Valparaiso. This would be consistent with infection with Trypanosoma cruzi. In his diary for 25 March 1835, while to the east of the Andes near Mendoza, he noted "an attack (for it deserves no less a name) of the Benchuca, a species of Reduvius, the great black bug of the Pampas". These are associated with transmittal of Trypanosoma cruzi causing Chagas' disease, but in subsequent days he does not mention the fever characteristic of first infection, which may have occurred in