rather large concretions, for near the walls several cylindrical and oval
pipes were intersected, which were lined with cellular matter and were
quite filled with free calciferous cells. A great enlargement in one
direction of several oval pipes would give rise to the lamell .
Besides the free calciferous cells in which no nucleus was visible, other
and rather larger free cells were seen on three occasions; and these
contained a distinct nucleus and nucleolus. They were only so far acted
on by acetic acid that the nucleus was thus rendered more distinct. A
very small concretion was removed from between two of the lamell within
an anterior gland. It was imbedded in pulpy cellular matter, with many
free calciferous cells, together with a multitude of the larger, free,
nucleated cells, and these latter cells were not acted on by acetic acid,
while the former were dissolved. From this and other such cases I am led
to suspect that the calciferous cells are developed from the larger
nucleated ones; but how this was effected was not ascertained.
When an anterior gland contains several minute concretions, some of these
are generally angular or crystalline in outline, while the greater number
are rounded with an irregular mulberry-like surface. Calciferous cells
adhered to many parts of these mulberry-like masses, and their gradual
disappearance could be traced while they still remained attached. It was
thus evident that the concretions are formed from the lime contained
within the free calciferous cells. As the smaller concretions increase
in size, they come into contact and unite, thus enclosing the now
functionless lamell ; and by such steps the formation of the largest
concretions could be followed. Why the process regularly takes place in
the two anterior glands, and only rarely in the four posterior glands, is
quite unknown. Morren says that these glands disappear during the
winter; and I have seen some instances of this fact, and others in which
either the anterior or posterior glands were at this season so shrunk and
empty, that they could be distinguished only with much difficulty.
With respect to the function of the calciferous glands, it is probable
that they primarily serve as organs of excretion, and secondarily as an
aid to digestion. Worms consume many fallen leaves; and it is known that
lime goes on accumulating in leaves until they drop off the parent-plant,
instead of being re-absorbed into the stem or roots, like various other
organic and inorganic substances. {46} The ashes of a leaf of an acacia
have been known to contain as much as 72 per cent. of lime. Worms
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