It was usually called “The Machine”. Each machine cost about three hundred livres to construct. They were usually made of fabric, leather, and stuffing and on occasion they would use actual human bones to form the torso. Various strings and straps serve to simulate the stretching of the birth canal and perineum, to demonstrate the process of childbirth.
The head of the infant mannequin has a shaped nose, stitched ears, hair drawn with ink, and an open mouth (with tongue) into which a finger could be inserted to a depth of 5 cm. This detail was important, as it allowed the midwife to put two fingers into the mouth, to facilitate the passage of the head in case of a breech presentation.
These mannequins were very detailed and also very accurate. The invention is often attributed to Englishman William Smellie, but the French Academy of Surgeons approved Du Coudray's model in 1758 giving her prior claim on the invention.
In 1759, King Louis XV commissioned her to teach midwifery to peasant women in an attempt to reduce infant mortality. Between 1760 to 1783, she travelled all over rural France, sharing her extensive knowledge with poor women. During this time, she is estimated to have taught in over forty French cities and rural towns and to have directly trained 4,000 students. She was also responsible for the training of 6,000 other women who were taught directly by her former students. She has also taught about 500 surgeons and physicians, who were all men.