Experiment No. 30
Microscopic Examination of Yeast
On a watch glass mix thoroughly a very small piece of yeast with about 5 cc. of water and then with the stirring rod place a drop of this solution on the microscopical slide, adding a drop of very dilute methyl violet solution. Cover with the cover glass and examine under the microscope. The living active cells appear colorless while the decayed and lifeless ones are stained. Yeast cells are circular or oval in shape. (See Fig. 46.)
(Adapted from Leach, "Food Inspection and Analysis.")