790 Kemp.—On the Question of the Occurrence of 
are lobed or amoeboid in shape (Fig. 11). One or more of the nuclei of such 
a group are frequently in process of disintegration and contain a fragmented 
nucleolus. Fibrillar structures are again visible throughout the root-tip, 
but vary greatly in their degree of definition, being conspicuous in some 
nuclei (Fig. io), whilst in others they are almost lacking. Polar caps are to 
be seen round the denser spiremes, but are still somewhat irregular and 
faintly stained. Many binuclear cells are visible, containing two small 
nuclei, lying close together in the cytoplasm, but quite round in outline and 
resembling those seen in Galtonia in fixations after 22 hours’ growth. In 
other such cells one of the two nuclei is often undergoing degeneration, 
being feebly stained and full of nucleolar bodies. 
3. After 48 hours subsequent growth. 
At this period of the experiment the appearance of the tissue as 
a whole is good, showing well-defined cell walls, unbroken cytoplasm, and 
nuclei which take up the stain strongly in all their constituents. At the 
same time there is an even greater number of notable structural peculiarities 
than at the preceding fixation, showing that the binuclear and tetraploid 
cells resulting from the action of the chloral hydrate have resumed division, 
while retaining the modifications due to that action. Scattered throughout 
the root-tip, and of considerably larger dimensions than their neighbours, 
these abnormal cells present a striking appearance. They occur most 
frequently in pairs, but here and there are to be seen in rows of four or five 
(cf. Fig. 3), the individual cells containing figures at all stages of activity. In 
some are to be seen equatorial plates or diasters of unusual size ; these, on 
counting their chromosomes with the camera lucida, are found to contain 
twice the normal somatic number. In others there are two separate division 
figures at the equatorial plate, diaster, or telophase stage, both of which 
figures are invariably in identical phases of activity, a point of considerable 
interest, as was noted above. In a few of the latter, fusion is taking place 
between the contiguous groups of the two telophases. In such cells 
as contained earlier a fragment of cell-plate as well as two nuclei, three 
walls are visible at the termination of the above division ; these consist 
of the thick fragmentary wall of the original arrested mitosis from which 
arose the binuclear condition of the cell, and the two thinner walls, generally 
oblique in position, formed during the double mitosis which has just occurred 
(Figs. 20, 21). Here and there in the permanent tissue is to be seen a much 
elongated cell with two nuclei ; these frequently appear to be lapsing into 
inactivity. The nucleoli seem to be very active at this period, staining 
deeply, and being broken up into several bodies and in some cases frag¬ 
mented into numerous minute globules. Large binuclear cells with their 
nuclei at rest are conspicuous, and in many of these one of the latter is dis¬ 
integrating (cf. Figs. 12 and 13). The abnormal figures just described are 
