Fig. 4. Photomicrographs of the product of release from Aiptasia pulchella after treatment with 25 mmol l^-1 caffeine. In A, the product was stained with 0.01 % fluorescein diacetate (x4000). Host cell cytoplasm is visible at the interstices of the algae; in B, the product was stained 0.01 % Hoechst 33258 (x4000). The host cell nucleus is visible adjacent to the algal doublet.