Bouillaud applied Laennec's technique of auscultation to diseases of the heart. Vol. 2, page 238: “Bouillaud’s disease” – rheumatic endocarditis. Although not first to note the cardiac manifestations of acute rheumatism, Bouillaud was the first to demonstrate the frequency and importance of heart disease co-incident with acute articular rheumatism. The above work includes the first description of a case of mitral disease with articular rheumatism. Translation of the section on the pathology of endocarditis in Willius & Keys, Cardiac classics, pp. 446-55.