most efficacious) was relatively greater at ordinary temperatures than
at the temperature of the body. It was found that whereas 10 cub. cent.
of a liquid containing the ordinary proportion of hydrochloric acid
digested 0.1311 gramme, a similar liquid prepared with butyric acid
digested 0.0455 gramme of fibrin.
Hence, taking the quantities digested with hydrochloric acid at the
temperature of the body as 100, we have the digestive power of
hydrochloric acid at the temperature of 16 to 18 Cent. represented by
44.9; that of butyric acid at the same temperature being 15.6.
We here see that at the lower of these two temperatures, hydrochloric
acid with pepsin digests, within the same time, rather less than half
the quantity of fibrin compared with what it digests at the higher
temperature; and the power of butyric acid is reduced in the same
proportion under similar conditions and temperatures. We have also seen
that butyric acid, which is much more efficacious than propionic or
valerianic acids, digests with pepsin at the higher temperature less
than a third of the fibrin which is digested at the same temperature by
hydrochloric acid.] [page 92]
I will now give in detail my experiments on the digestive power of the
secretion of Drosera, dividing the substances tried into two series,
namely those which are digested more or less completely, and those
which are not digested. We shall presently see that all these
substances are acted on by the gastric juice of the higher animals in
the same manner. I beg leave to call attention to the experiments under
the head albumen, showing that the secretion loses its power when
neutralised by an alkali, and recovers it when an acid is added.
Substances which are completely or partially digested by the Secretion
of Drosera.
Albumen. After having tried various substances, Dr. Burdon Sanderson
suggested to me the use of cubes of coagulated albumen or hard-boiled
egg. I may premise that five cubes of the same size as those used in
the following experiments were placed for the sake of comparison at the
same time on wet moss close to the plants of Drosera. The weather was
hot, and after four days some of the cubes were discoloured and mouldy,
with their angles a little rounded; but they were not surrounded by a
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