[Maternal imagination and congenital malformations].

Since antiquity philosophers and scientists tried to explain the cause of congenital malformations. In early modern medicine maternal imagination was largely accepted as their true cause, This concept was rejected by Blondel, a London physician. Around 1750 Wolff introduced the Hemmungsbildung as the cause of congenital malformations, a concept adopted in 1781 by Blumenbach. Later on Soemmerring (1784), Crichton (1785) and Meckel the younger adopted Blumenbach's concept. In 1824 Suringar further developed it. More and more the excessive development of fetal blood vessels or nerves was rejected as a possible cause, although from time to time these ideas were adopted again. In the early 1800s Etienne Geoffroy Saint-Hilaire (1811) and Vrolik (1817) developed a classification of monstra. These attempts urged Isidore Geoffroy Saint-Hilaire (Etienne's son) and Vrolik the younger (Gerard's son) to develop it further. Nevertheless, around 1840 Vrolik had to admit that although we are well acqainted with the various malformations, we are still ignorant of the primary cause of these phenomena. Meanwhile the dispute between the adherents of the theory of preformation and those who had adopted the concept of epigenesis exercised many minds. In the second half of the eighteenth century the latter theory became more and more adopted and this fact cleared the way for the ideas introduced by Wolff and Blumenbach, because it was consistent with the idea of a gradual development of fetal structures.