Osborne, on the Wheat Plant, 
131 
said that this plasm, though clearly elastic, at times gives the 
appearance, when broken up, of broken glass. Under the 
twelfth power, nuclei which I have managed to break within 
their cells, present the appearance of minute glass beads of 
coloured glass which have been crushed. It is true the 
nuclei grown in this solution differ from any I have before 
seen, in their extreme minuteness, the utter invisibility of the 
granules mthin them ; still, there they are with their nucleoli 
in situ. The pigment has made them tell a tale which I 
scarcely think any other means would have extracted from 
them. 
Note. 
Since the above paper was read, at a meeting of the Micros- 
copical Society, I have made some farther investigation into 
the origin and growth of those vessels of which I have spoken, 
as pitted, scalariform, annular, and spiral. The earliest stage 
at which I can trace this vascular form, is in the shape of cell- 
wall, with very minute pits or depressions arranged in an 
order with regard to each other, either linear or spiral, the 
cells themselves being generally ovate. As soon as their 
termini become absorbed, and they thus become portions of a 
continuous tube, the pits are seen to enlarge and assume a 
long oval character ; these pits are based with a very thin 
membrane, and in this a small dark spot is perceived, the 
commencement, as I believe, of actual perforation. At the 
next stage the entire basement membrane has become 
absorbed, and the perforation of the cell- wall is now complete 
in a series of oval apertures. In some instances these are so 
directly in line that, as they elongate and break into each 
other, the tube- wall is cut into straight lines, consisting of 
that part of its texture which existed between the original 
rows of pits ; and thus those bars are produced which charac- 
terise the ladder-like tube seen in the root of the wheat, and 
in other portions of many plants. 
For a considerable time I was perplexed by observing cer- 
tain dots or circular spaces, whose close conjunction at the 
ends of the bars, formed as it were, the sides of the ladder of 
which the bars were the steps ; I at length solved the mystery ; 
I find these vessels, at that stage of their growth when they 
assume the scalariform appearance, are pentagonal, the dots 
being nothing more than the action of the light at the angles, 
the dis^ided cell-wall being also at the said angles rather 
thicker than at any other portion. I have made preparations 
clearly proving this to be the case in transverse sections of 
