374 G. CARL HUBER 
from rat No. 104, 6 days after insemination. In the uterus of 
this rat there were found six ova. In both of these rats, the ova 
present essentially the same stage of development, comparable to 
that shown in A and B of figure 28, Part I. As may be observed 
from the text of Part I (page 301) the stages obtained at the 
end of the sixth day and early hours of the seventh day, were 
found very difficult to fix. At this stage the ovum consists of a 
relatively large, thin walled vesicle, very prone to fixation shrink- 
age. All of the ova or vesicles obtained from rats Nos. 91 and 
104, are very badly folded in their roof portion. Those shown 
Fig. 7 Two ova of the albino rat partly surrounded by maternal blood with 
many phagocytic leucocytes. The folding of the roof of the vesicles is due to 
fixation shrinkage. X 200. A, rat No. 91, 5 days, 16 hours, after the beginning 
of insemination. B, rat No. 104, 6 days after the beginning of insemination. 
in A and B, figure 7, are representative. This folding, a result 
of imperfect fixation, is present in all of the vesicles of this stage, 
even though the respective vesicles present normal structure. 
The ova here figured may be regarded as having fairly normal 
structure, both as to rate of development and as to arrange- 
ment, form, and structure of constituent cells. All of the eight 
vesicles obtained from these two rats (No. 91, 2 ova; No. 104, 6 
ova) are in part surrounded by exudated maternal blood, con- 
taining numerous leucocytes. Small masses of blood with leu- 
cocytes are found here and there in different parts of the uterine 
lumen of both rats, lodged in mucosal folds other than the char- 
acteristic decidual crypts enclosing the respective ova. These 
