290 Ha rquette, Manifestations of polarity in plant cells whtcli usw. 
results, the ends being drawn out as it were to needle points. 
The polar starch-bodies round up more and more so that by the 
time the chromosomes are arranged on the equatorial plate they 
have once more a more or less irregulär spherical shape. The sharp 
spindle poles press into these irregularly spherical polar structures 
producing an appearance not unlike that obtained when a pointed 
body presses into a mass of stiff dough. (Fig. 5.) We are here 
dealing with an actual indentation of the surface of the rounded 
polar structure and not with an appearance such as is sometimes 
met with in the astrospheres of animal cells. Here namely, if the 
spindle-ends extend into the astrosphere a part of the sphere is 
replaced by them though a superficial Observation might give the 
impression that here too the spindle indents the sphere. This is 
especially true of those cases in which there are differences in the 
staining reactions of spliere-rays and spindle fibers, or where the 
spindle fibers are closely packed and distinctly fibrous while the 
sphere has more of a granulär appearance. It requires but a glaiice, 
however, to show that in these cases the appearance is due to 
the absence of a sector of the astral rays and their replacement 
by the spindle fibers, and not to an indentation of the surface of 
the sphere. 
The completed spindle of the young leaf-cells of Isoeies is made 
up of numerous fibers. They are delicate, unusually clean cut, and 
closety packed; the result is a spindle of sharp outline which Stands 
out in strong contrast to the pale cytoplasm surrounding it. In 
fact, the surrounding cytoplasam at this stage seems to consist of 
little but watery cell-sap; the Strands or lamellae of its more solid 
constituents are delicate and widely separated. The relation between 
tlie spindle and the surrounding cytoplasm is only imperfectly 
represented in Fig. 5, the spindle shonld be considerably darker in 
comparison to the surrounding cytoplasm. It is to be noted that 
there is a definitely fixed relation between the position of the polar 
structures and the axis of the spindle. Without exception tlie 
spindle lies so that its ends press into approximately tlie middle 
of the polar structures. This invariable relation Stands out with 
especial clearness when, as is not seldom the case, tlie polar 
structures lie at diagonally opposite corners of the cell. In these 
cases the spindle also lies diagonally so that here as always its 
ends indent the approximate centers of the polar structures. 
Occasionally it happens that the spindle figure lies far over at one 
side of an unusualty broad cell with the spindle axis parallel to 
the side of the cell, and in these cases the polar structures also 
show the same degree of displacement towards tlie side of the 
cell. In this connection Strasburger’s conception 1 ) of tlie anchoring 
of the spindle figure in those cases in which its poles do not reach 
to the plasma membrane comes to mind. He assumes that tlie 
dense trophoplasmic layer which frequently surrounds the spindle 
figure in these cases and into which the spindle-poles extend 
b Hist. Beitr. VI p. 152. 
