[Ultrastructural localization of the oxydasic activity in Toxoplasma gondii (author's transl)].

Toxoplasma belonging on the RH strain were studied under a transmission electron microscope. The activities looked for were: peroxidase, cytochrome oxydase and acid phosphatase. An oxydasic cytochrome respiratory activity was seen. It is localised on the crests and on the peripheral membrane of the mitochondria of Toxoplasma gondii. In the given experimental conditions, no such activity appeared in the other intracytoplasmic organels of the parasite, nor in the vacuoles of the host-cells containing living toxoplasma but the organels of those host-cells presented an oxydasic activity.