This is a picture of my microscopic pets, paramecium caudatum, fed with dyed yeast cells.
I used Congo red for dying the yeast, because Congo red is an indicator for pH too :http://en.wikipedia.org/wiki/Congo_red
red with pH above 5.2, blue below pH 3. First the ingested yeast cells are colourful red in the feeding vacuoles,
later they turn to blue, a wonderful and easy to do experiment.
Thanks for looking,
Gerd
