with special reference to the occurrence of Amitosis, etc. 373 
Various instances of lobed nuclei have been described in the 
higher plants, especially among the Monocotyledons, but the case of 
“Stratiotes differs from all those previously recorded in two points— 
‘firstly, that the lobing 1s of a markedly regular and uniform type, 
and secondly, that 2 occurs, not only in the root-cap, which may 
well be regarded as a somewhat abnormal tissue, but also in the 
developing cortex and stele. 
_ The appearance of a lobed nucleus will be more clear! y under- 
stood by reference to Pl. [X, Figs. 6—9, than from description. It 
is better shown in Pl. IX, Figs. 7—9, which were drawn from hand 
sections, than in Pl. IX, Fi ig. 6, for which microtome sections were 
employed. In studying amitosis it is important to view the 
nucleus as a whole, but in microtome sections the knife is apt 
‘to mutilate it, and there is also more danger of distortion, owing 
to the necessary preliminary treatment and the heating in the 
‘paraffin. The result is that hand sections, though so little used 
in general cytology, become of special value in this particular 
case. A comparative study of the lobed nuclei, as seen in micro- 
tome and hand sections, shows that in almost every instance there 
is originally an indentation on one side only, the nucleus retaining 
its convex form on the opposite side and presenting the general 
appearance of a so-called “resting” nucleus (Pl. IX, Fig. 9e). The 
two lobes appear, at early stages, to be unequal in size, the one 
which contains the nucleolus “being the larger. At later stages 
the two lobes seem to become equalised, and the nucleus ultimately 
has the appearance of being almost bisected. There is generally 
a nucleolus in each lobe, due possibly to the division of the original 
‘single one, while sometimes a third occurs in the median plane 
i(ef. “the cell marked xin Pl. IX, Fig. 9a). The nuclei in the cells 
marked y, y’, « and z in Pl. IX, Fig. 6 show different stages in the 
lobing of the nucleus, and similar stages can be followed in Pl. IX, 
i Big. 9. Occasionally two nuclei are seen lying closely side by side 
as if one of the lobed nuclei had just separated completely into two 
(PL IX, Fig. 9c). 
— (1) Interpretation. 
_ The first questions which arise, in considering the observations 
recorded above, are whether the phenomenon which I have de- 
‘scribed as “lobing” of the nucleus is natural or artificially induced, 
and, if it is natural, whether it is normal or pathological. I think 
‘we may conclude that it is natural, since I have observed it in 
‘material fixed in methylated spirit, acetic alcohol, and Flemming’s 
ne solution. It has however been suggested to me that it may 
be an abnormality, possibly due to the poisoning of the roots during 
life by some substance present on the water, such as marsh gas. 
This ; is, of course, conceivable, but it seems to me unlikely. It is 
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