From extracts of one collection of kidney worms, nine components were separated; eight contained antigens, some of which were common to all. From a second collection, four components absorbing strongly at 280 mje (and presumed to be largely protein) and seven carbohydrate components were separated; three of the former and five of the latter contained two antigens that were common to all eight. One of the protein components contained a third antigen. Thus, a number of presumed protein components and a number of carbohydrate components were separated without clearly isolating more than one antigen. Whole swine kidney worm (Stephanurus dentatus) extracts have been used previously as an antigen in agar diffusion precipitation tests for diagnosis of experimental stephanuriasis (Tromba and Baisden, 1960). This paper reports attempts to separate antigenic components of such extracts on the DEAE-cellulose (diethylaminoethyl-cellulose anion exchanger) adsorbent of Peterson and Sober (1956). MATERIALS AND METHODS Collection of worms and sera: Worms of two collections were washed free of adhering host tissue. Collection 1, consisting of approximately equal numbers of juveniles and sexually mature adults, weighed 17.8 g after the worms were blotted. Collection 2, consisting of about 66 juveniles for every 34 adults, weighed 16.4 g. Because collection was slow, overnight storage at 4 C of some worms of each collection was unavoidable. Sera used are described elsewhere (Tromba and Baisden, 1963). Preparation and test of extracts: The worms were covered with 0.05 M Na2HPO4 and subjected to five ultrasonic treatments at 9 kc/sec for 5 min. The more fluid portion of the resulting brei was decanted after each treatment and immediately centrifuged at 17,300 g for 30 min. The total volume of the five clarified extracts was 50 ml for collection 1 and 48 ml for collection 2. The extracts were preserved with a final concentration of 0.003% sodium ethylmercurithiosalicylate and stored at 4 C. Ouchterlony (1949) tests against serum from infected swine were made on the individual extracts. Chromatography and test of collection 1 Eight-ml portions of each clarified extract were pooled (P-1). Part of the pool was recentrifuged Received for publication 29 September 1961. and concentrated eightfold by pressure dialysis. The concentrate was chromatographed by the procedure of Fahey, McCoy, and Goulian (1958) except that at tube 91 (Fig. 2) 0.3 M NaH2PO, adjusted to pH 3.0 with HCI was substituted for the elution mixture. Four 7-ml fractions/hr were obtained at 4 C from a column of adsorbent 2.5 cm in diameter and 20 cm high. The pH and optical density (OD) at 280 and 260 mjt of each fraction were determined (Fig. 2) and fractions showing peaks of OD at 280 were tested. Then fractions on either side of a peak fraction were pooled with it. This pool of fractions is considered to contain a protein component, and it is referred to as such, hereafter, although it is recognized that substances absorbing strongly at