DR. MARTIN BARRY’S RESEARCHES IN EMBRYOLOGY. 
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had disappeared. They were very transparent, and their membranes 
had a high refracting power. 50 diam. 
Fig. 210. An ovum of thirty-five hours, found in the Fallopian tube between its 
middle and the uterus. It measured in diameter about yo'". The four 
cells ( bs ) constituting the essential portion of the ovum — each measu- 
ring about — unlike those in the preceding figure, were of equal size. 
They were globular, except that where in contact with one another, 
some degree of flattening had occurred ; though this was scarcely (if 
at all) perceptible when they were first seen. In their transparency 
and the high refracting power of their membranes, they resembled the 
cells of the preceding figure. Their contents seemed more advanced. 
In all, the minute central pellucid space had disappeared. A larger 
space now presented itself, filled with transparent cells of considerable 
size, around which were very minute ones comparatively opake (par. 
353. 357.). The structure of all the cells contained within the four, 
appeared to be essentially the same as that of the cells represented in 
the preceding figures ; and it is deserving of notice that the contained 
cells were not globular, like the parent cells, but elliptic in their form 
(par. 355.). 100 diam. 
Fig. 211. An ovum of thirty-six hours, found in the Fallopian tube, and measuring 
in diameter — . It was taken from the same Rabbit as the ovum 
fig. 212, and the objects in figs. 21 3 A. and 213 B. In the centre of 
this ovum were five cells. Three of these, larger than the rest and glo- 
bular, corresponded to three of the four in the preceding figure. The 
other two, smaller and elliptical, appeared to be a new generation that 
had been contained within a cell corresponding to the fourth of those 
in the preceding figure, the membrane of which had disappeared. The 
remaining three larger cells exhibited a generation of two cells (the in- 
tended successors of the parent cell), besides others of minuter size. 
(These minuter cells would have undergone liquefaction along with the 
membrane of the parent cell (par. 354.).) 100 diam. 
Fig. 212. An ovum of thirty-six hours, found in the Fallopian tube, and measuring 
in diameter y ". It was taken from the same Rabbit as the ovum in 
fig. 211, and the objects in figs. 213 A. and 213 B. Four cells — corre- 
sponding to those in fig. 210. — having each given origin in its interior 
to two (persistent cells), the number present in this ovum was eight (bs). 
These cells — originally elliptical (see the corresponding ones in fig. 
211.) — were now globular, but flattened where in contact with one 
another. They were exceedingly transparent. Their membranes had 
a high refracting power, and they contained other cells. Among the 
latter, two were in most instances easily distinguishable by their central 
