tried, and these acted rather differently from fresh gluten. One leaf
was almost fully re-expanded in three days, and the other three leaves
in four days. The chips were greatly softened, almost liquefied, but
not nearly all dissolved. The glands which had been in contact with
them, instead of being much blackened, were of a very pale colour, and
many of them were evidently killed.
In not one of these ten cases was the whole of the gluten dissolved,
even when very small bits were given. I therefore asked Dr. Burdon
Sanderson to try gluten in artificial digestive fluid of pepsin with
hydrochloric acid; and this dissolved the whole. The gluten, however,
was acted on much more slowly than fibrin; the proportion dissolved
within four hours being as 40.8 of gluten to 100 of fibrin. Gluten was
also tried in two other digestive fluids, in which hydrochloric acid
was replaced by propionic [page 119] and butyric acids, and it was
completely dissolved by these fluids at the ordinary temperature of a
room. Here, then, at last, we have a case in which it appears that
there exists an essential difference in digestive power between the
secretion of Drosera and gastric juice; the difference being confined
to the ferment, for, as we have just seen, pepsin in combination with
acids of the acetic series acts perfectly on gluten. I believe that the
explanation lies simply in the fact that gluten is too powerful a
stimulant (like raw meat, or phosphate of lime, or even too large a
piece of albumen), and that it injures or kills the glands before they
have had time to pour forth a sufficient supply of the proper
secretion. That some matter is absorbed from the gluten, we have clear
evidence in the length of time during which the tentacles remain
inflected, and in the greatly changed colour of the glands.
At the suggestion of Dr. Sanderson, some gluten was left for 15 hrs. in
weak hydrochloric acid (.02 per cent.), in order to remove the starch.
It became colourless, more transparent, and swollen. Small portions
were washed and placed on five leaves, which were soon closely
inflected, but to my surprise re-expanded completely in 48 hrs. A mere
vestige of gluten was left on two of the leaves, and not a vestige on
the other three. The viscid and acid secretion, which remained on the
discs of the three latter leaves, was scraped off and examined by my
son under a high power; but nothing could be seen except a little dirt,
and a good many starch grains which had not been dissolved by the
hydrochloric acid. Some of the glands were rather pale. We thus learn
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