Eugen Gabritschevsky was supposed to be a scientist. Born in 1893 to an eminent Russian bacteriologist and privately educated with his four brothers and sisters, he painted and drew compulsively even as a child, but spent the Revolution earning a biology degree at Moscow University; did postdoctoral research in Paris, New York and Edinburgh; and published widely. Altogether, he spent nearly 40 years learning to impose order, in the form of names, theories, and family trees, on the chaos of the natural world.

But an escalating series of nervous breakdowns drove him, in 1931, to Munich, where his brother Georges lived, and where he spent most of the rest of his life confined to a psychiatric hospital. Unable to continue his scientific ...