Developmental Abnormalities in the Rat Induced by Heat Shock

A simple method for applying heat shock directly to the uterus of pregnant rats is described. In an experimental series a temperature of 40–41 °C. was maintained for 40 min. A number of malformed foetuses were observed, and the resorption rate was high. In a control series animals were operated upon in the same manner as the experimental ones, but the temperature was kept at 37–38°C. No malformations were found. Deformities of the head and extremities were produced by the heat shock. These malformations are compared with those produced by other teratogens, and the differences are discussed.