PLATE 1 
EXPLANATION OF FIGURES 
2 Epithelial cells of the prooestrous vaginal smear. > 800. Cytoplasm _ 
takes a blue or purple tinge when stained with haematoxylin and eosin. _ 
3 Epithelial cells of oestrous vaginal smear. > 800. The nuclei have | 
their affinity for basic dye; the cells are cornified and stain a bright red with 
eosin. ees 
