Abstract
The various phases of pulmonary aspergilloma, as described by Pimentel, are discussed and the results of an investigation of possible cases of this disease in patients whose condition made its presence likely are presented. A systematic search for Aspergillus precipitins in the sera of 136 patients was undertaken with A. fumigatus antigens. By this method two cases of pulmonary aspergilloma were diagnosed and later confirmed at operation. In a third patient the immunological diagnosis was negative but an aspergilloma was found at operation. This finding is discussed and a possible hypothesis is suggested. A pathological study of the surgical specimens is desirable to explain the false-negative Aspergillus precipitin reactions reported by various authors.