Staining of toxoplasma in histological sections.

EXTRACELLULAR toxoplasma, although present in abundance in smears from animals infected experimentally, can only occasionally be found in sections from suspected toxoplasma lesions. In the eye, Wilder (1952a, b) has described organisms morphologically indistinguishable from toxoplasma in cases of granulomatous uveitis, but even in these sections the organisms were not numerous and were found only after a careful search. Pinkerton and Weinman (1940) stated that Giemsa's was the most satisfactory stain for these organisms, but it is not suitable for use on celloidin sections of the eye, and a search has been made for a more useful stain for demonstrating these parasites. The need for such a stain was further emphasized by the occurrence of lesions associated with serological evidence of toxoplasmosis in which the organisms could not be demonstrated.