The rectoscopic biopsy is a new clinical method devised to increase the diagnostic frequency of infections of Schistosoma mansoni. It was published in an earlier paper with Dr. H. Atencio M. in 1943 (1). At the time of the appearance of this paper the diagnostic percentage obtained in Caracas, Venezuela with stool examinations ranged from 2 to 9 per cent depending on the number of examinations performed on each patient, and the type of human material examined (outpatients, hospital, or sanatorium patients). The diagnostic percentage in autopsy material examined histologically was about 20 per cent.
The rectoscopic biopsy method is based on certain fundamental facts that we elicited while studying autopsy material. By digesting with caustic potash according to the method recommended by Fergusson (2), and then examining the sediment microscopically we demonstrated a 45 per cent infection with S. mansoni in liver fragments taken from autopsies.