Abstract
In order to investigate the cellular elements of vaginal smear of the bitch in the estrous cycle, 32 mongrel bitches 24 years of age weighing about 10 kg each were observed during approximately 130 days from 3 months before proestrus to 10 days after estrus.
Vaginal smears were collected every day using a metal spatula at any time between 8 and 9 a. m. Various cell components contained in the vaginal smear were divided into 4 groups; -(non), ± (a few), + (moderate), and ?? (numerous), on the basis of the number of cells which appeared.
A smear was air-dried quickly, fixed in 90 per cent methanol and stained with Giemsa solution.
The results obtained are as follows.
1. Pre-proestrus.
Leucocytes, epithelial cells and cornified epithelial cells were always low in count in the cons-tituents of smear. In two-thirds of the animals the latter two increased slightly in count over a period from 1 to 1.5 months before vulval bleeding could be recongnized by the naked eye.
Erythrocytes were observed in smear for only several days from 40 to 50 days before vulval bleeding. The consistent appearance of erythrocytes began to be observed in smear 7 days on the average (020 days) before vulval bleeding.
2. Proestrus (317 days, or 8.4 days on the average).
Cornified epithelial cells increased gradually. Epithelial cells and leucocytes were hardly found in numerous animals in the late stage of this phase. Erythrocytes increased in count in the early phase, but decreased gradually in the latter half of this phase.
3. Estrus (520 days, or 11.1 days on the avarage).
Epithelial cells and leucocytes began to appear in the vaginal smear again in late estrus.
Cornified epithelial cells decreased moderately in about half of the animals in the latter half of this phase.
In some animals, erythrocytes stained indistinctly were absent from smear in this phase.
4. Metestrus.
A few epithelial cells and cornfied epithelial cells were found in vaginal smears during post-estrus. Leucocytes increased temporarily in about half of the animals. Erythrocytes appeared moderately in smears in about two-thirds of the animals studied. As mentioned above, it was found that various cell elements changed rhythmically in the vagi-nal smear in relation to the ovarian cycle in numerous bitches. Four bitches (13%), however, showed no periodical changes. So that, it was difficult to decide the estrous cycle accurately by examining vaginal smears alone.
