We have attempted to develop a reasonable approach to the diagnosis of a case that we are reporting, that of a 6 months fetus presenting a generalized bullous eruption. The usual diagnoses of syphilis, pemphigus neonatorum and epidermolysis bullosa could apparently be excluded. The study has been made under the following divisions : 1. A classification and brief review of fetal dermatology. 2. The relation of the infectious diseases to pregnancy and the fetus. 3. A review of forty-seven reported cases of fetal variola and presentation of a case believed to be pemphigoid fetal vaccinia. DERMATOLOGIC CONDITIONS OF THE FETUS Most examples of fetal cutaneous pathology are due to genetic imperfections. Unna 1 pointed out that the group which he calls Missbildungen is constantly expanding. Tumors form another large percentage of cutaneous conditions in the fetus. Only a small number of bullous eruptions are seen. A review