The Virus of Psittacosis

Abstract

Purified suspensions of psittacosis virus were prepared from infected chorio-allantoic membranes and centri-fuged at high speeds. The virus could not be completely removed from the supernatant fluid, using hand sampling methods, but the elementary bodies were concentrated and washed. The washed suspensions were completely or almost completely retained by Berkefeld V, W and N and Chamberland L3 candles and Seitz EK pads, but highly satisfactory filtration was obtained using the Bauer and Hughes'' type of graded collodion membrane. On the basis of ultrafiltration experiments, the infective particle of psittacosis was found to have a minimum diameter of 0.2 to 0.3 u, a figure corresponding to the size of the elementary body as determined by photomicrographic methods.