The small
ramifying tubules might at first sight be taken for some traces of a
vegetable tissue, but my colleague, Dr. Scott, assures me that they do
not in the least resemble any tissue found in the bamboo. I have myself
no doubt that it is an inorganic structure. It is not improbably
analogous to the peculiar ramifying tubules formed in a solution of water
glass when a crystal of copper sulphate is suspended in it, as shown by
Dr. Heaton (Proc. Brit. Assoc., 1869, p. 127). Similar forms also occur
on a larger scale in some agates, and the artificial cells of Traube may
probably be regarded as analogous phenomena.
The aggregates of globular bodies seen in the section so greatly resemble
the globulites of slags and natural glasses, and in their arrangement so
forcibly recall the structures seen in the well known pitchstone of
Corriegills in Arran, that one is tempted to regard them as indicating
the beginnings of the development of crystalline structure in the
tabasheer. But I have good grounds for believing the structure to have a
totally different origin. They seem in fact to be the portions of the
mass which the fluid Canada balsam has not succeeded in penetrating. By
heating they may be made to grow outward, and as more balsam is imbibed
they gradually diminish, and finally disappear.
I must postpone till a future occasion a discussion of all the structures
of this remarkable substance and of the resemblances and differences
which they present to the mineral opals on the one hand, and to those of
the opals of animal origin found in sponge spicules, radiolarians, and
the rocks formed from them, some of which have recently been admirably
investigated by Dr.
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