This volume examines the influence of a teratological agent on early avian development, especially the chondracranium. Cranial abnormalities developing from the experimental application of ethyl alcohol on genetically and nutritionally uniform chick embryos are described in detail and compared to the normal stages of development. A full discussion and evaluation are provided regarding the gross abnormalities and malformations observed in microscopical and histological investigations. The value of avian material for the experimental application of teratogenic material is also demonstrated.