One of the more common viral infections affecting man is that caused by the herpes simplex virus. Its most common manifestation, the "fever blister," is so familiar to the layman that a medical diagnosis is not sought.However, the manifestations of the herpes virus are so protean that they may range from severe encephalitis, to the moderately severe stomatitis frequently seen in the very young, to the mild "fever blister" just mentioned. The more severe manifestations are due to a primary infection which occurs after an incubation period of three to five days, whereas the "fever blister" is felt to be the result of an upset in an otherwise symbiotic relationship between host and virus. Between 65% and 98% of adults, depending on areas sampled, will show neutralizing antibodies to the herpes simplex virus.Since the initial case report of herpes simplex infection in the newborn by Haas 1 in 1935 it has been recognized that the herpes virus is capable of producing a widespread disseminated disease of the newborn which involves structures of ectodermal origin as well as those of entodermal and mesodermal origin. After this report by Haas, Zuelzer,2 in 1952, reported five infants with pathologi¬ cal evidence of disseminated herpetic infec¬ tion, one of which was proved on culture to have been caused by the herpes simplex virus. This report and subsequent ones have described the disease as being characterized by the onset of a systemic reaction on or about the fifth to seventh day post delivery with fever or hypothermia, increasing icterus, lethargy, respiratory distress, vomiting, dyspnea, cyanosis, and with rapid develop-