Abstract
Summary Sonic vibration was used to disintegrate or modify the contaminating white and red cells found in the exudate from mice infected with Toxoplasma and then trypsin was employed to digest the modified cells together with particulate and amorphous debris derived from disintegrated cells. Trypsin and digested substances were then removed by washing and centrifugation. After preliminary experiments were performed to determine suitable conditions of treatment, 10 purified samples were prepared and tested with the following average results: purity 98.7% ± 0.88; recovery 39.4% ± 8.911; average level of infectivity in another three experiments showed 7.6% of the original samples.