used, though less soluble than fibrin, of which, as we have seen, 1.31
was dissolved. I wish that I had tried on Drosera globulin prepared by
this method. [page 121]
globulin were not corroded or rounded by the secretion of Drosera,
though some soluble matter was certainly extracted from them and
absorbed by the glands.
Haematin. Some dark red granules, prepared from bullock s blood, were
given me; these were found by Dr. Sanderson to be insoluble in water,
acids, and alcohol, so that they were probably haematin, together with
other bodies derived from the blood. Particles with little drops of
water were placed on four leaves, three of which were pretty closely
inflected in two days; the fourth only moderately so. On the third day
the glands in contact with the haematin were blackened, and some of the
tentacles seemed injured. After five days two leaves died, and the
third was dying; the fourth was beginning to re-expand, but many of its
glands were blackened and injured. It is therefore clear that matter
had been absorbed which was either actually poisonous or of too
stimulating a nature. The particles were much more softened than those
kept for the same time in water, but, judging by the eye, very little
reduced in bulk. Dr. Sanderson tried this substance with artificial
digestive fluid, in the manner described under globulin, and found that
whilst 1.31 of fibrin, only 0.456 of the haematin was dissolved in an
hour; but the dissolution by the secretion of even a less amount would
account for its action on Drosera. The residue left by the artificial
digestive fluid at first yielded nothing more to it during several
succeeding days.]
_Substances which are not Digested by the Secretion._
All the substances hitherto mentioned cause prolonged inflection of the
tentacles, and are either completely or at least partially dissolved by
the secretion. But there are many other substances, some of them
containing nitrogen, which are not in the least acted on by the
secretion, and do not induce inflection for a longer time than do
inorganic and insoluble objects. These unexciting and indigestible
substances are, as far as I have observed, epidermic productions (such
105