A 3.5 g quantity of bushbaby fur was defatted with 100 mℓ CCl4 for 5 min and air dried. It was then mixed with 17.5 mℓ of pyrogen-free buffered saline, placed on a magnetic stirrer, and extracted for 48 hr in the cold. Following centrifugation, the clean supernate yielded 1960 μg/protein/mℓ. This was also diluted to contain 100,000 P.N.U./mℓ. Both the serum and skin test antigens were filter-sterilized with 0.45 μm cellulose acetate membrane prior to skin testing. Using the prepared antigens, skin tests were done intradermally using dilutions containing 1000 P.N.U./mℓ in 0.02 mℓ amounts and the diameter of the resulting wheal, if any, measured.