434 RAYMOND M. SELLE 
carried into the vagina. In order to avoid any confusion that 
might be caused by the presence of uterine mucus and cells, 
in seven of the twenty females the uterine horns were tied off 
posterior to the oviducts and anterior to the cervix and the inter- 
mediate pieces excised. ‘The value of this operation was not 
sufficient to warrant its recommendation. Although the con- 
tents of the vaginae in the animals which had been hysterecto- 
mized were freer from mucus and consequently more easily diag- 
nosed, there was not a great difference between smears made 
from these animals and smears made from normal guinea-pigs. 
A careful scrutiny of successive vaginal smears of twenty 
guinea-pigs over a period of seven months disclosed a succession 
of cell changes in the contents of the vagina substantially similar 
to that described by Stockard and Papanicolaou for the guinea- 
pig and by Long and Evans for the rat. The enumeration of the 
stages in this paper follows that employed by Long and Evans. 
CHANGES IN VAGINAL SMEARS AND HISTOLOGY OF VAGINAL 
EPITHELIUM 
Interval of dioestrum 
If the vaginal smears of a number of guinea-pigs were to be 
examined, it would be found that most of them would contain 
many leucocytes and few, small, round epithelial cells; in fact, 
this condition would be found to be characteristic during three- 
fourths of the time in any one pig. While the nature of the smear 
does not seem to vary during this period there are, however, his- 
tological changes in the mucosa. 
The lining of the vagina of a guinea-pig consists of a stratified 
epithelium, the upper surface of which is nearly even, while the 
side in contact with the submucosa, from which it is clearly de- 
marked, appears insection to be deeply lobed as though furrowed, 
the effect being produced by tongue-like projections of the sub- 
mucosa extending up into the epithelium. The epithelium thus 
seems to vary in thickness (figs. 1 and 8). The whole mucosa is 
further thrown into larger longitudinal folds. 
ove = 4 a 
age ee 
