CYTOLOGICAL STUDIES OF CENTRIFUGED EGGS 605 
(2) Should the egg fall so that the spindle lies at the outer end, 
and comes, in consequence, to lie in the yolk, it is rarely or never 
displaced by the yolk. In hundreds of such cases examined I have 
found very few that might possibly be interpreted to mean that 
the spindle had been displaced by the yolk. The yolk may com- 
pletely surround the outer pole of the spindle, and obliterate or 
obscure the astral rays, but the spindle remains nevertheless near 
the surface in the same way as does the second polar spindle 
under like circumstances. 
(3) Should the egg fall so that the spindle lies at the oil pole 
the results are very different. The outer end of the spindle in the 
oil is destroyed, in part, or entirely, so far as can be judged from 
preserved material (plate 4, fig. 7) ; or the spindle is displaced 
more towards the center of the egg, and in some such cases the 
polar rays seem to be largely lost (fig. 8). Even when the spindle 
stands obliquely with one end at the edge of the oil cap, those of 
its fibres that extend into the region of the cap are lost; their loss 
m&y be due either to displacement by the oil, or to the tendency 
of the oil droplets to flow together into larger drops that press the 
fibres out of position. It is not a little surprising to find such a con- 
trast between the effect of the oil and of the yolk on the spindle. 
The difference may be due in part, as just suggested, to the tend- 
ency of the oil drops to unite, while no such effect is produced in 
the yolk, and also in part to a greater difference in specific gravity 
between the oil and the spindle, than between the yolk and the 
spindle. 
After the first polar body has been formed the inner mass of 
chromatin is carried over into the second polar spindle. It has 
not been possible to move the chromatin at any time during the 
transition period. The experiment should be repeated, however, 
on eggs in which a resting nucleus, that could, no doubt, be moved, 
appears at this time; for, it would be highl}' important to know if, 
under these conditions, the second polar body would be suppressed 
or develop at some other point of the egg, or whether the nucleus 
or chromatin would be drawn back to the polar regions. 
The only case that I have observed of displacement of the sec- 
ond polar spindle is shown in plate 4, fig. 9, in which the spindle, 
in metaphase, has been pushed inwards from the surface. I have 
