REPRODUCTION 67 



Vaginal smears. — Three methods are in common use for taking vaginal 

 smears, i. Pipette or lavage method. A pipette drawn to a rather fine 

 point and containing a few drops of water is inserted into the vagina, the 

 water ejected and immediately sucked in again. The water with its cellular 

 contents can then be transferred to a slide for examination. 2. Spatula or 

 curette method. Some of the cell contents of the vagina can be removed by 





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Fig. 34. — Photographs of vaginal smears stained with haematoxylin-eosin. A. 

 Diestrus. B. Late estrus. (X300.) 



means of a spatula or, preferably, a fine curette. The cells are transferred 

 to a drop of water on a slide by tapping the curette on the slide. 5. Cotton 

 swab method. Cells can be removed with a fine, moist, cotton swab on the 

 end of a toothpick. It has been shown that frequent smearing with cotton 

 swabs will produce cornification of the vagina in spayed rats and mice, hence 

 leading to a smear that indicates estrus though in animals in which true 

 estrus cannot occur (133). The cycle in normal animals may likewise be 

 disturbed by this method of smearing (40) which is, therefore, not to be 

 recommended. The lavage method is less upsetting (40, 41). The curette 

 method is probably also satisfactory though it has been noted that frequent 



