Osborne^ on the Wheat Plant. 
113 
form of the cells I had seen to separate by an apparent 
splitting of the beaded division ; the use of a high power now 
enabled me to see at the inner edge of the coloured portion 
of the cell, the growth of the future line of division. 
I have just said that the cell- walls will not take up the 
coloured matters I use ; the viscous hyaline matter in which 
the formative granules and molecules float will do so to a 
certain degree. I am inclined to think this is of a diff'erent 
nature from what I have called " epidermic plasm." I am of 
opinion that all the granular and molecular matter I class as 
" formative matter " exists imbodied in a very thick trans- 
parent fluid, that it is this which efi'ects the various combi- 
nations of cell- contents ; I have succeeded in colouring it, 
but 1 have my doubts whether the tint I have given does not 
in reality proceed from exceedingly small coloured granules, 
which are so closely incorporated with it as to impart their 
own tinge ; when a well-filled and coloured cell is bruised out 
upon a slide, the intimate connection between the coarser 
material and this viscous matter is clearly shown. 
The epidermic plasm I have never yet found to take any 
colour from any of the means I have used to paint the in- 
ternal matter of the cells; although so elastic as to often 
resist the strongest attempts I can make to separate it 
from the structures it invests, when broken up, its edges 
have the appearance of broken glass. I believe this plasm 
to be equally the integument of every individual cell, as 
it is of every combination of cells. In portions that I 
have succeeded in detaching, I have observed the vesicles 
containing nuclei, the latter highly coloured ; also the early 
stage of the beaded network of which I have spoken. 
It is impossible to value too highly the help given to the 
study of cell-growth, from the use of colouring matters 
applied to the growing plant. Amongst others it reveals this 
curious fact — that the smaller the organism into which the 
pigment can enter the more highly painted will it appear 
(PL IV, figs. 23, 28). This arises, I believe, from the cir- 
cumstance of the formative matter being more closely packed 
in the smaller spaces into which it is received ; the plasm 
enveloping colour and formative matter alike, when it con- 
tracts upon them to form the nuclei, so closely aggregates 
the granules that their whole mass acquires a deep colour. 
In the small cells, which are so beautifally distributed in 
the vascular bundle, the walls preserve their fall transpa- 
rency, the contents take an evident amount of colour ; a clear 
outline shows the vesicles containing the nuclei ; these nuclei 
are seen very highly coloured. You have thus under the 
