114 
Osborne, on the Wheat Plant, 
object-glass several generations of growth, each painting 
itself with a distinctive shade drawn from a common 
source of identical colour (PI. IV, figs. 24, 25) . Under every 
feature of cell-growth, the nuclei and the aggregations of 
formative matter which tend to nucleolar growth, will always 
be found to present a much deeper colour than the formative 
matter in the same cell with them. 
I do not consider all masses of formative matter, tending to 
the globular form, within cells, as nuclei. There will often be 
a mass of granular contents, somewhat globular, seen at one 
edge of the middle of a cell (PI. IV, fig. 14), on which it is 
impossible to make out any membranous investment ; it will 
gradually increase by taking to itself more of the mass of 
similar matter contained in the cell, or by its own expansion, 
until it occupies a very large portion of the cell- cavity ; a line 
of separation then appears above and below it, caused by the 
formation of two new cell-walls or divisions in the cell, in 
which this process is taking place; this mass of granular 
matter now assumes a quadrangular outline, entirely filling a 
space separated for it in the cell by the new walls. The 
portions cut off" by the interposition of this new formation 
increase by expansion, as it does itself, and thus one cell 
becomes three (PI. IV, fig. 27) . 
With regard to the true nuclei, those with a well-defined 
outline and the nucleolus within them ; before these take any 
visible part in the work of cell-propagation, with scarce an 
exception, I see the gradual formation of the egg-shaped 
vesicle of which I have spoken ; this vesicle is seen to increase 
its proportions, the nucleus for some time remaining inactive 
at the broader end; a new cell is thus formed, apparently 
within an old one ; when it has attained a matured dimension 
the nucleus seems to break up or disperse within it ; after an 
interval a new nucleolar formation is seen, prepared, I assume, 
to follow the same course. 
Besides these processes of cell- growth — that from an 
irregular aggregation of cell-contents (PI. IV, figs. 16, 17, 18), 
and that by the vesicular investment of a nucleus — there are 
combinations of cell-contents into masses with oval and other 
outlines, which I cannot trace as taking any part in ceU-pro- 
pagation ; they will often be seen in the matured parenchyma, 
of a long, oval form. I am inclined to regard them simply 
as a secretion from the cell-walls, often absorbed, to be again 
secreted in the same form. 
In portions of a plant where the growth is very vigorous I 
frequently find two, sometimes three, nuclei in one cell, very 
often two in one vesicle (PI. IV, fig. 28) . The use of colouring 
