Qualitative analysis refers to those examinations which relate simply to the presence or the absence of certain substances, irrespective of their quantities.
The sublimates should be carefully observed, as they indicate often with great certainty the presence of certain substances; for instance, that of arsenic.
We use those reagents, or tests, for the purpose of ascertaining the presence or the absence of certain substances, through the peculiar phenomena produced when brought in contact with them.
Certain substances known as galactosides, which are combinations of galactose and some substances other than carbohydrates, are found in the nerve and brain tissues of the animal body.
The chemical changes in the food materials, after they are eaten, are brought about through the action of certain substances known as soluble ferments or "enzymes.
The Specific Gravity~ of urine is one of the points by means of which the presence of certain substancesmore or less abnormal in character is determined.
The diet employed in making these tests consists of different amounts of certain substances known to be diuretic in character.
Certain substances, called enzymes, formed by glands cause the digestion of food.
Certain substances found in the body wastes from animals are necessary to the life of a green plant.
Certain substances in the bile aid especially in the absorption of fats.
It is probable that many of the chemical transformations in physiological processes, such as digestion, are assisted by certain substancesacting as catalytic agents.
If, however, certain substances such as common salt are dissolved in the water, the resulting solutions are found to be conductors of electricity.
Photography is based on this property in certain substances (for instance, in the salts of silver).
Among the phenomena accompanying the combustion of certain substances, the phenomenon of flame attracts attention.
Eckstein on the comparative deodorising values of certain substances.
Facilitating induction; susceptible of being acted upon by induction; as certain substances have a great inductive capacity.
Tooth edge, the sensation excited in the teeth by grating sounds, and by the touch of certain substances, as keen acids.
The above list will hopefully provide you with a few useful examples demonstrating the appropriate usage of "certain substances" in a variety of sentences. We hope that you will now be able to make sentences using this group of words.
