Jean Pecquet, a French anatomist, born in Dieppe about 1620, died in February, 1674. He studied at Montpellier, and while still a student made the most important anatomical discovery of his life, namely, the true course of the lacteal vessels. He found that the mesenterio lacteal vessels terminate in a saccular expansion situated at the upper and back part of the abdomen, next the vena cava and in front of the second lumbar vertebra, now known as the receptaculum chyli, or the reservoir of Pecquet; and that the chyle is thence conducted by the thoracic duct to the point where this canal opens into the left subclavian vein. It is said that this discovery did much to induce the acceptance of Harvey's doctrine of the circulation of the blood. Pecquet spent the greater part of his life in Paris, and was one of the first members of the academy of science. His principal works are Ex-perimenta nova Anatomica (Paris, 1651), and De Girculatione Sanguinis et Chyli Motu, and De Thoracicis Lacteis (1654).