OSBORNE, ON VEGETABLE GROWTHS.
87
stated that many of the grains of Greensand accompanying
the well-defined casts are of wholly unrecognisable forms,
having merely a rounded, cracked, lobed, or even coprolitic
appearance. Certainly many of these masses, which often
compose whole strata, were not formed either in the cavities
of Polythalamia or Mollusks. The fact, however, being established, beyond a doubt, that Greensand does form casts in
the cavities of various organic bodies, there is a great probability that all the masses of this substance, however
irregular, were formed in connection with organic bodies;
and that the chemical changes accompanying the decay of
the organic matter have been essentially connected with the
deposits in the cavities, of green and red silicates of iron, and
of nearly pure silica. It is a curious fact in this connection,
that the siliceous organisms, such as the Diatomacese, Polycistinese, and Spongiolites, which accompany the Polythalamia
in the Gulf Stream, do not appear to have any influence in
the formation of casts.
The discovery by Professor Ehrenberg, of the connection
between organic bodies and the formation of Greensand, is
one of very great interest, and is one of the many instances
which he has given to prove the extensive agency of the
minutest beings in producing geological changes.
Further OBSERVATIONS on VEGETABLE GROWTH.
By the Hon. and Rev. SIDNEY GODOLPHIN OSBORNE.
IT may interest the readers of the ' Journal' to knoAv that
further observation has given me a deeper insight into the
structure of the wheat plant in the earliest stage of its
growth. I find there is a " circulation " in every one of the
long suckers put forth from the roots; it may be seen very
plainly under a power of 800. Although I can trace it with
ease along the outer edge of each sucker, running from the
root towards the blunt point, I cannot trace any current returning towards the root.
In the case of the spiral fibre in the early plumule, I now
find it to have in every case its own investment; that, in fact,
it is within a tube of very thin cellular texture. By careful
management of the light, lines running vertically the whole
length of this tube can.be seen; I presume these to be the
outlines of a fine wall of cells, of which this tube is formed.
The coils of fibre, if attached at all to this tube, are only
partially so, as I have succeeded by pressure in extending a
88
OSBOB.NE, ON VEGETABLE GROWTHS.
coil without disturbing in any way the tube itself. That they
exercise considerable pressure upon the tube, at the points
where the coils are close, is quite evident by the extension
that they there clearly give to it.
Although I have failed in every endeavour to make out the
existence of spiral fibre in the grain of wheat, in other vegetables I can clearly trace it, but only in the embryo seed. A
very fine section of a young " vegetable marrow," made so as
to pass through the embryo seeds, will show coils of spiral
fibre passing from the flesh of the fruit into these seeds; and
at the narrow extremities of each seed, it can with ease be
made out with a power of 500. The embryo seeds are, in
fact, connected with the fruit by a small bundle of this fibre.
I believe this to be the case with the wheat, and I have little
doubt but that a careful dissection of the attachment of each
grain in an ear of such corn, made at the time when the
grains are just assuming their form, would prove it.
I have been much interested by a continued close study of
the "double ovate" vesicles to be ever found imbedded in
the plasm in which, if not from which, the root cells of the
wheat root are formed. I have the strongest impression that
these are the earliest organisms of plant life, so far, at least,
as the roots of plants are concerned. I will not now hazard
the publication of all the extraordinary features I have observed in them; one, however, not the least extraordinary, I
will mention. I have now preparations of the formative
matter of the wheat root, sealed hermetically more than six
months since, and floating in "Thwaites's fluid," the double
ovate cells of which are in as active a motion at this time as
they were the day I put them up from the growing root. By
the use of the twelfth power B eye-piece, and good light,
they may be seen to have taken up the pigment in which I
have grown the plants; indeed, I am now satisfied it is by
their close aggregation within the cells of the roots, that I
get the rich colour I do, when the plants are grown in
coloured media. The divisions of my micrometer eye-piece,
with the twelfth power, as given me by Mr. Ross, are -j-srinr
(0*000074). One of these active vesicles will occupy rather
more than one of these divisions. The movement of these
minute bodies is very different from the molecules of gamboge
and other substances; I have never seen anything the least
resembling it, except in preparations I have made from prepared glasses, exposed for a time to the atmosphere in the
early days of summer, when the air is full of spores.
What life it is I know not, but I believe it to be positively
life.