Examinations of wet mounts and iron hematoxylin stained sediments preserved in PVA-fixative from 878 diagnostic fecal cultures were made, and the results compared. Of a total of 391 infections found by the two examinations, 366 infections (or 94 per cent) were identified in the stained films as compared to 212 (or 56 per cent) identified in the wet mounts of the same cultures. The increased number was due (a) to the addition of infections found only in the stained films and (b) to the identification of infections seen but not identified in the wet mounts. The numbers of infections of all five species of amebae were increased to varying degrees.
The sediment from routine diagnostic fecal cultures for amebae can be fixed with PVA-fixative and stained by permanent staining techniques with good results. In order to reduce the work involved in the cultivation procedure, it is suggested that the preparation of stained smears be reserved for those cultures in which organisms are observed in wet mounts. In this study 94 per cent of the infections would have been identified by this limited number of examinations of stained slides (250 slides rather than 878).