Liber de rheumatismo et pleuritide dorsale.

De Baillou is usually credited with introducing the term “rheumatism”. He was court physician in Paris at the time of Henri IV. His book, the first on rheumatism, was translated into English by C. C. Barnard in Brit. J. Rheum., London, 1940, 2, 141-62. (According to Webb Dordick, the antiquarian bookseller Emil Offenbacher pointed out in his catalogue 28, item 94, a use of the word rheumatism as early as 1577:  Petrus Pichotus. De rheumatismo . . . , Bordeaux, 1577.)  A digital facsimile of Pichotus's book is available from Google Books at this link.