What is "substances"

Usage examples of "substances".

In like manner, the glands of the stomach of animals secrete pepsin, as Schiff asserts, only after they have absorbed certain soluble substances, which he designates as peptogenes.

The several substances, which are completely dissolved by the secretion, and which are afterwards absorbed by the glands, affect the leaves rather differently.

We shall hereafter see that solutions of these substances, when placed on the discs of leaves, do not incite inflection.

Now, it is a remarkable fact, which affords additional and important evidence, that the ferment of Drosera is closely similar to or identical with pepsin, that none of these same substances are, as far as it is known, digested by the gastric juice of animals, though some of them are acted on by the other secretions of the alimentary canal.

I have observed the same leaf with the tentacles closely inflected over rather indigestible substances, such as chemically prepared casein, pouring forth acid secretion for eight successive days, and over bits of bone for ten successive days.

From these and numerous other experiments not worth giving, it is certain that inorganic substances, or such organic substances as are not attacked by the secretion, act much less quickly and efficiently than organic substances yielding soluble matter which is absorbed.

I may here add, as showing that the leaves are not acted on by the odour of nitrogenous substances, that pieces of raw meat stuck on needles were fixed as close as possible, without actual contact, to several leaves, but produced no effect whatever.

Ziegler makes still more extraordinary statements with respect to the power of animal substances, which have been left close to, but not in contact with, sulphate of quinine.

I made a vast number of trials by placing, by means of a fine needle moistened with distilled water, and with the aid of a lens, particles of various substances on the viscid secretion surrounding the glands of the outer tentacles.

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.

Even small doses are more or less poisonous, probably on the same principle that raw meat and other nutritious substances, given in excess, kill the leaves.

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.

Nothing more need be said about some of the above enumerated substances, excepting that they were repeatedly tried on the leaves of Drosera, and were not in the least affected by the secretion.