Teratogenic activity of several closely related disazo dyes on the developing chick embryo.

THEt eratogenic activity of several disazo dyes during rat embryogenesis has been investigated by Wilson (1955). In addition to the marked teratogenicity of trypan blue Wilson also demonstrated that Evans blue was moderately active and that Niagara blue 4B and Niagara sky blue 6B were possibly active. On the other hand, several other closely related disazo dyes such as Congo red and azo blue were found to cause no malformations in the surviving offspring. Since trypan blue has been shown to be teratogenic to the chick embryo (Beaudoin & Wilson, 1958), it is of interest to determine whether other disazo dyes that have been tested in the rat affect the chick embryo in the same or a similar manner.