treated with a solution which had been kept during several days in a
warm room, and their glands were not at all affected when examined
after 21 hrs.
A weaker solution of one part of urea to 437 of water was next tried on
six summits, all carefully examined before being irrigated. The first
was re-examined after 8 hrs. 30 m., and the glands, including the
spherical ones, were brown; many of the oblong glands having their
primordial utricles much shrunk and including granules. The second
summit, before being irrigated, had been somewhat affected by the
surrounding water, for the spherical glands were not quite uniform in
appearance; and a few of the oblong ones were brown, with their
utricles shrunk. Of the oblong glands, those which were before
colourless, became brown in 3 hrs. 12 m. after irrigation, with their
utricles slightly shrunk. The spherical glands did not become brown,
but their contents seemed changed in appearance, and after 23 hrs.
still more changed and granular. Most of the oblong glands were now
dark brown, but their utricles were not greatly shrunk. The four other
specimens were examined after 3 hrs. 30 m., after 4 hrs., and 9 hrs.; a
brief account of their condition will be sufficient. The spherical
glands were not brown, but some of them were finely granular. Many of
the oblong glands were brown, and these, as well as others which still
remained colourless, had their utricles more or less shrunk, some of
them including small aggregated masses of matter.]
A Summary of the Observations on Absorption. From the facts now given
there can be no doubt that the variously shaped glands on the valve and
round the collar have the power of absorbing matter from weak solutions
of certain salts of ammonia and urea, and from a putrid infusion of raw
meat. Prof. Cohn believes that they secrete slimy matter; but I was not
able to perceive any trace of such action, excepting that, after
immersion in alcohol, extremely fine lines could sometimes be seen
radiating from their [page 422] surfaces. The glands are variously
affected by absorption; they often become of a brown colour; sometimes
they contain very fine granules, or moderately sized grains, or
irregularly aggregated little masses; sometimes the nuclei appear to
have increased in size; the primordial utricles are generally more or
less shrunk and sometimes ruptured. Exactly the same changes may be
observed in the glands of plants growing and flourishing in foul water.
The spherical glands are generally affected rather differently from the
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