Adler, Saul. "Darwin's Illness," Nature 184 (10 October 1959), pp. 1102-1103.
This is the source of the hypothesis that Darwin's illness was Chagas' disease. Adler, a
parasitologist at Hebrew University in Jerusalem suggests that an overlooked incident, written of
in Darwin's journal, told of Darwin being bitten by that "bug of the pampas, the benchuca,"
which is known as a carrier of Chagas' disease. This author suggests that while there is no way of
proving that Darwin had that illness, there are two things which are known: 1) Darwin's
symptoms can be well fitted with the disease, (at least as well as they can be forced into the
psychogenic diseases), and 2) it is possible to pinpoint a definite incident in which Darwin was
exposed to the disease.
Adler overstates the vector's probability of being infectious, possibly to enhance the quality of
his hypothesis, and he overlooks some evidence that contradicts the diagnosis. Namely, Darwin
did not report any of the early symptoms which would presumptively have affected him on the
Beagle, and it was several years later that he developed the symptoms which would fit Chagas'
I note that while there are many who would prefer to have Darwin suffering from a real disease
rather than hypochondria, there are problems with any theory with a biological basis. His own
physicians couldn't find anything wrong with him and, most telling, he got better as he grew
older. Nonetheless, the Chagas' disease hypothesis has good reasons for gaining acceptance.