Credé, in 1879, advocated prevention of ophthalmia neonatorum by cleansing the birth canal with 2 per cent phenol solution and placing 1 drop of 2 per cent silver nitrate solution into the eyes of the newborn. The drop in the incidence of ophthalmia, following the adoption of the Credé method, according to Lehrfeld,1 was due to the attempted cleansing of the birth canal rather than to the instillation of silver nitrate into the eye. Survey of the Department of Public Health records of Philadelphia for fifteen years (1920 to 1935), showed, according to Lehrfeld, that ophthalmia neonatorum has not materially decreased despite the general application of Credé's method.
Lehrfeld found, in an analysis of the records of 28,000 births occurring in six hospitals over a period of five years, that the incidence of ophthalmia neonatorum amounted to 2.2 per cent. Sorsby and his co-workers in England found in a