PLATE 1 
EXPLANATION OF FIGURES 
1 (Microphotograph.) Longitudinal section of the vagina at the middle 
of the interval, showing the finger-like processes of the submucosa projecting up 
into the epithelium. The submucosa contains many blood vessels. The epithe- 
lium is thinnest at this time, being only one or two cell layers. %X 115. 
2 (Microphotograph.) Longitudinal section of the vagina near the cervix 
at the end of the interval, about twenty-four hours before stage 1, showing the 
epithelium at its greatest height, about ten cells. The uppermost cells are 
greatly enlarged and vacuolated and are the superficial epithelial cells found in 
vaginal smears during stage 1. Leucocytes are seen in the lumen. X 115. 
3 (Microphotograph.) Longitudinal section of the vagina during stage 1. 
Some. of the large irregular epithelial cells characteristic of stage 1 are seen in 
the lumen along with a few leucocytes. The uppermost layers of cells have begun 
to slough off. About three or four cells below the surface of these superficial 
epithelial cells the cornifying layers are seen as flattened and more darkly stained 
cells. XX 115. 
4 (Microphotograph.) Longitudinal section of the vagina during stage 1, 
showing the well-formed cornified layers splitting from the stratum granu- 
losum below and the process of cornification extending up into the superficial 
epithelial layers above. X 115. 
444 
OE 
