Alexandre Jean Baptiste Parent-Duchatelet (1790-1835) was a French physician and one of the most eminent hygienists of the nineteenth century. In 1814, he wrote his inaugural thesis on cholera. After an unsuccessful attempt to establish a private practice, he devoted himself to public health. His numerous works included essays on the Paris sewers (1822), the influence of tobacco on the health of workmen in tobacco factories (1829), the effect of emanations from putrifying animal matter on food substances (1831), steeping of hemp in relation to public health (1832), sanitation of dissecting rooms (1835), and prostitution in the city of Paris in relation to public health, morality and administration, La prostitution dans la ville de Paris, (1836). This last publication, which appeared posthumously, is an epoch-making work and ranks as a medical classic.