failed to digest fresh gluten, apparently from its injuring the glands,
though some was absorbed. Raw meat, unless in very small bits, and
large pieces of albumen, &c., likewise injure the leaves, which seem to
suffer, like animals, from a surfeit. I know not whether the analogy is
a real one, but it is worth notice that a decoction of cabbage leaves
is far more exciting and probably nutritious to Drosera than an
infusion made with tepid water; and boiled cabbages are far more
nutritious, at least to man, than the uncooked leaves. The most
striking of all the cases, though not really more remarkable than many
others, is the digestion of so hard and tough a substance as cartilage.
The dissolution of pure phosphate of lime, of bone, dentine, and
especially enamel, seems wonderful; but it depends merely on the
long-continued secretion of an acid; and this is secreted for a longer
time under these circumstances than under any others. It was
interesting to observe that as long as the acid was consumed in
dissolving the phosphate of lime, no true digestion occurred; but that
as soon as the bone was completely decalcified, the fibrous basis was
attacked and liquefied with the greatest ease. The twelve substances
above enumerated, which are completely dissolved by the secretion, are
likewise dissolved by the gastric juice of the higher animals; and they
are acted on in the same manner, as shown by the rounding of the angles
of albumen, and more especially by the manner in which the transverse
striae of the fibres of muscle disappear.
The secretion of Drosera and gastric juice were both able to dissolve
some element or impurity out of the globulin and haematin employed by
me. The secretion also dissolved something out of chemically [page 131]
prepared casein, which is said to consist of two substances; and
although Schiff asserts that casein in this state is not attacked by
gastric juice, he might easily have overlooked a minute quantity of
some albuminous matter, which Drosera would detect and absorb. Again,
fibro-cartilage, though not properly dissolved, is acted on in the same
manner, both by the secretion of Drosera and gastric juice. But this
substance, as well as the so-called haematin used by me, ought perhaps
to have been classed with indigestible substances.
That gastric juice acts by means of its ferment, pepsin, solely in the
presence of an acid, is well established; and we have excellent
evidence that a ferment is present in the secretion of Drosera, which
likewise acts only in the presence of an acid; for we have seen that
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