Aggie is a 3 year-old Large Munsterlander (yes - that is a real breed) noticed to have a swollen vulva and to be spotting blood. A series of vaginal smears were taken, the first labeled as Day 1.
Go through the images presented below and classify each as being proestrus, estrus or diestrus (the text box provided under the images is for taking notes). To gain the most from this exercise, DO NOT click the "Show clues" checkbox until you are finished evaluating the slides.
When you have completed your assessment of these images, click on the "Show clues" box and go through them again to view the author's classification.