they in the following experiment.
Another flower-stem was placed in the same manner and for the same
length of time in a solution of one part of nitrate of ammonia to 146
of water (or 3 grs. to 1 oz.), and the glands were discoloured in
exactly the same manner as by the infusion of raw meat.
Another flower-stem was immersed, as before, in a solution of one part
of carbonate of ammonia to 109 of water. The glands, after 1 hr. 30 m.,
were not discoloured, but after 3 hrs. 45 m. most of them had become
dull purple, some of them blackish-
* In the case of Saxifraga tridactylites, Mr. Druce says
( Pharmaceutical Journal, May 1875) that he examined some dozens of
plants, and in almost every instance remnants of insects adhered to the
leaves. So it is, as I hear from a friend, with this plant in Ireland.
[page 347]
green, a few being still unaffected. The little masses of protoplasm
within the cells were seen in movement. The cells of the pedicels were
unaltered. The experiment was repeated, and a fresh flower-stem was
left for 23 hrs. in the solution, and now a great effect was produced;
all the glands were much blackened, and the previously transparent
fluid in the cells of the pedicels, even down to their bases, contained
spherical masses of granular matter. By comparing many different hairs,
it was evident that the glands first absorb the carbonate, and that the
effect thus produced travels down the hairs from cell to cell. The
first change which could be observed is a cloudy appearance in the
fluid, due to the formation of very fine granules, which afterwards
aggregate into larger masses. Altogether, in the darkening of the
glands, and in the process of aggregation travelling down the cells of
the pedicels, there is the closest resemblance to what takes place when
a tentacle of Drosera is immersed in a weak solution of the same salt.
The glands, however, absorb very much more slowly than those of
Drosera. Besides the glandular hairs, there are star-shaped organs
which do not appear to secrete, and which were not in the least
affected by the above solutions.
Although in the case of uninjured flower-stems and leaves the carbonate
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