58 Proceedings of the Royal Physical Society. 
persistence occurs in all cases of mitosis, and that the apparent absence 
of the nuclear membrane in preparations is due to the destructive action 
of fixing agents; but his view that the nuclear membrane contracts 
around each individual: chromosome obviously does not hold good for 
Amoeba) 
The spindle itself appears to be multiple in character, imperfectly 
divided into a number of constituent spindles, each one of which has its 
axis parallel to the long axis of the nucleus. These elementary spindles 
are arranged side by side, in a row which is perpendicular to the long 
axis of the whole nucleus, and extends practically throughout its whole 
width. Whether the centrosome apparatus is diffuse or, on the other 
hand, multiple, with a distinct centrosome at each spindle apex, cannot be 
made out with certainty in the preparation. 
The number of elementary spindles appears to be four or five, the 
limits of the two at the right edge of the section (Fig. la) being difficult 
to define, but the one at the extreme left of section (Fig. 2a) stands out 
most distinctly, leaving practically no doubt of the plurality of spindles. 
The equatorial plate is distinctly seen under a very low magnification, 
while under high powers the chromosomes can be counted, although, owing 
to the oblique plane of section, there is occasionally a certain amount of 
indefiniteness of outline and consequently of individuality. 
Another result of the obliquity is that the spindle with its chromosomes 
appears in two sections, and the sparsity of the chromosomes in the 
second (Fig. 2a) shows that, had the plane of the sections been absolutely 
parallel to that of the central axis, one section would have enclosed the 
whole of the equatorial plate with its spindle fibres. This proves clearly 
the statement, already made, that the spindles are arranged not around a 
central axis but in a row 20, in length and having an average breadth— 
from apex to apex of the spindles—of 15, the multiple spindle thus 
forming a band about 4-5 thick lying in the nucleus. This might 
suggest, perhaps, a possible explanation of peculiar appearances often 
occurring in the nucleus of whole preparations of A. proteus. 
The chromosomes of the equatorial plate have evidently just passed 
through the process of division, as the separated daughter-chromosomes 
are distinctly visible at the bases of the spindle fibres. As already 
mentioned, a glance at the section (Fig. la) under low and moderately 
high powers gives the impression of four or five spindles, each spindle 
carrying about ten daughter-chromosomes, giving roughly 50 chromosomes. 
1 Trans. Roy. Soc. Hdin., vol. xlviii., part 1 (No. 7), p. 144. 
