Prepare the sample of fresh stool. Using applicator sticks, place small amounts of faeces on clean, sterile microscope slides. producing extremely tiny streaks of the sample. Do not dry the slides, and immediately place them in Schaudinn's fixative for 30 minutes. If the stool sample is watery, place three to four drops of PVA on the smeared slide (slide with a stool sample) and mix well. Allow the slide to dry for several hours at 35° – 37°C or overnight at room temperature.