Experimental.
—The section on congenital deformities in "Progress in Orthopedic Surgery for 1941" opened with an account of Warkany's work on the production of skeletal abnormalities in the offspring of rats fed on a deficient diet. During 1942 he and his associates have reported further on the same work. They1 point out that it has been asserted often that faulty nutrition of the fetus may be a cause of congenital malformations. The faulty nutrition may have its origin in various disturbances. Faulty implantation of the ovum, diseases of the placenta, interruption of the umbilical blood flow, toxic substances transmitted through the placenta and deficiencies in the diet of the mother have been suggested as causes of deformities in the mammalian embryo or fetus. The last-mentioned cause has aroused new interest in recent years. Warkany and Nelson give the following summary of the work:1. Skeletal abnormalities occurred in about